FUJITSU SEMICONDUCTOR DATA SHEET DS04-27262-3E ASSP for Power Management Applications (General-Purpose DC/DC Converter) 2ch PFM/PWM DC/DC converter IC with synchronous rectification MB39A136 DESCRIPTION MB39A136 is 2ch step-down DC/DC converter IC of the current mode N-ch/N-ch synchronous rectification method. It contains the enhanced protection features, and supports the symmetrical-phase method and the ceramic capacitor. MB39A136 realizes rapid response, high efficiency, and low ripple voltage, and its highfrequency operation enables the miniaturization of inductors and I/O capacitors. FEATURES * * * * * * * * * * * * * * * High efficiency For frequency setting by external resistor : 100 kHz to 1 MHz Error Amp threshold voltage : 0.7 V 1.0% Minimum output voltage value : 0.7 V Wide range of power-supply voltage : 4.5 V to 25 V PFM/PWM auto switching mode and fixed PWM mode selectable Supports Symmetrical-Phase method With built-in over voltage protection function With built-in under voltage protection function With built-in over current protection function With built-in over-temperature protection function With built-in soft start/stop circuit without load dependence With built-in synchronous rectification type output steps for N-ch MOS FET Standby current : 0 [A] Typ Small package : TSSOP-24 APPLICATION * * * * * * * * * Digital TV Photocopiers Surveillance cameras Set-top boxes (STB) DVD players, DVD recorders Projectors IP phones Vending machine Consoles and other non-portable devices Copyright(c)2008-2011 FUJITSU SEMICONDUCTOR LIMITED All rights reserved 2011.3 MB39A136 PIN ASSIGNMENT (TOP VIEW) CTL1 1 24 CB1 CS1 2 23 DRVH1 FB1 3 22 LX1 COMP1 4 21 DRVL1 ILIM1 5 20 VCC RT 6 19 VB VREF 7 18 GND CTL2 8 17 DRVL2 ILIM2 9 16 LX2 COMP2 10 15 DRVH2 FB2 11 14 CB2 CS2 12 13 MODE (FPT-24P-M09) 2 DS04-27262-3E MB39A136 PIN DESCRIPTION Pin No. Symbol I/O 1 CTL1 I CH1 control pin. 2 CS1 I CH1 soft-start time setting capacitor connection pin. 3 FB1 I CH1 Error amplifier inverted input pin. 4 COMP1 O CH1 error amplifier output pin. 5 ILIM1 I CH1 over current detection level setting voltage input pin. 6 RT Oscillation frequency setting resistor connection pin. 7 VREF O Reference voltage output pin. 8 CTL2 I CH2 control pin. 9 ILIM2 I CH2 over current detection level setting voltage input pin. 10 COMP2 O CH2 error amplifier output pin. 11 FB2 I CH2 Error amplifier inverted input pin. 12 CS2 I CH2 soft-start time setting capacitor connection pin. 13 MODE I PFM/PWM switch pin. (CH1 and CH2 commonness) It becomes fixed PWM operation with the VREF connection, and it becomes PFM/PWM operation with the GND connection. 14 CB2 CH2 connection pin for boot strap capacitor. 15 DRVH2 O CH2 output pin for external high-side FET gate drive. 16 LX2 CH2 inductor and external high-side FET source connection pin. 17 DRVL2 O CH2 output pin for external low-side FET gate drive. 18 GND Ground pin. 19 VB O Bias voltage output pin. 20 VCC Power supply pin for reference voltage and control circuit. 21 DRVL1 O CH1 output pin for external low-side FET gate drive. 22 LX1 CH1 inductor and external high-side FET source connection pin. 23 DRVH1 O CH1 output pin for external high-side FET gate drive. 24 CB1 CH1 connection pin for boot strap capacitor. DS04-27262-3E Description 3 MB39A136 BLOCK DIAGRAM MODE RT 13 VCC 6 20 <CH1> <Soft-Start, Soft-Stop> CS1 2 VREF ctl1 /uvp_out /otp_out 5.5 A - /uvlo ovp_out COMP1 FB1 <PFM Comp. > + pfm1 70 k <I Comp.> - + + 180 out of phase RS-FF RQ - + S intref ILIM1 19 VB pfm2 ch.1 ch.2 <Error Amp> Bias Reg. 2.0 V 4 3 Clock generator 24 Hi-side Drive 23 Drive Logic 22 CB1 DRVH1 LX1 VB CLK 5 21 Lo-side Drive Vs DRVL1 Level Converter <Di Comp.> <OVP Comp.> <UVP Comp.> + - - + intref x 1.15 V - + intref x 0.7 V ovp1 uvp1 <UVLO> ovp1 ovp2 uvp1 uvp2 50 s delay 512/fOSC delay ovp_out SQ R SQ uvp_out VB UVLO uvlo H:UVLO release otp_out R CS2 12 VREF UVLO OTP <CH2> The configuration of a control circuit is the same as that of CH1. 14 15 COMP2 FB2 10 16 11 17 CB2 DRVH2 LX2 DRVL2 VB ctl1, ctl2 ILIM2 9 <REF> <CTL> intref (3.3 V) 7 VREF 4 ON/OFF CTL1 1 8 CTL2 18 GND DS04-27262-3E MB39A136 ABSOLUTE MAXIMUM RATINGS Parameter Symbol Conditions Rating Min Max Unit Power-supply voltage VVCC VCC pin 27 V CB pin input voltage VCB CB1, CB2 pins 32 V LX pin input voltage VLX LX1, LX2 pins 27 V 7 V Voltage between CB and LX Control input voltage Input voltage VCBLX VI CTL1, CTL2 pins 27 V VFB FB1, FB2 pins VVREF + 0.3 V VILIM ILIM1, ILIM2 pins VVREF + 0.3 V VCSx CS1, CS2 pins VVREF + 0.3 V MODE pin VVB + 0.3 V VMODE Output current IOUT DC DRVL1, DRVL2 pins, DRVH1, DRVH2 pins 60 mA Power dissipation PD Ta + 25 C 1644 mW - 55 + 150 C Storage temperature TSTG WARNING: Semiconductor devices can be permanently damaged by application of stress (voltage, current, temperature, etc.) in excess of absolute maximum ratings. Do not exceed these ratings. DS04-27262-3E 5 MB39A136 RECOMMENDED OPERATING CONDITIONS Parameter Symbol Conditions Power supply voltage VVCC CB pin input voltage Value Unit Min Typ Max 4.5 25.0 V VCB 30 V Reference voltage output current IVREF - 100 A Bias output current IVB -1 mA CTL pin input voltage VI CTL1, CTL2 pins 0 25 V VFB FB1, FB2 pins 0 VVREF V VILIM ILIM1, ILIM2 pins 0.3 1.94 V VCS CS1, CS2 pins 0 VVREF V MODE pin 0 VVREF V Input voltage VMODE Peak output current IOUT DRVH1, DRVH2 pins DRVL1, DRVL2 pins Duty 5% (t = 1/fOSC x Duty) - 1200 + 1200 mA Operation frequency range fOSC 100 500 1000 kHz Timing resistor RRT RT pin 47 k Soft start capacitor CCS CS1, CS2 pins 0.0075 0.0180 F CB pin capacitor CCB CB1, CB2 pins 0.1 1.0 F VREF pin 0.1 1.0 F VB pin 2.2 10 F - 30 + 25 + 85 C Reference voltage output capacitor CVREF Bias voltage output capacitor CVB Operating ambient temperature Ta WARNING: The recommended operating conditions are required in order to ensure the normal operation of the semiconductor device. All of the device's electrical characteristics are warranted when the device is operated within these ranges. Always use semiconductor devices within their recommended operating condition ranges. Operation outside these ranges may adversely affect reliability and could result in device failure. No warranty is made with respect to uses, operating conditions, or combinations not represented on the data sheet. Users considering application outside the listed conditions are advised to contact their representatives beforehand. 6 DS04-27262-3E MB39A136 ELECTRICAL CHARACTERISTICS (Ta = + 25 C, VCC pin = 15 V, CTL pin = 5 V, VREF pin = 0 A, VB pin = 0A) Symbol Pin No. Conditions Output voltage VVREF 7 Input stability VREF LINE Load stability Short-circuit output current Parameter Reference Voltage Block [REF] Typ Max 3.24 3.30 3.36 V 7 VCC pin = 4.5 V to 25 V 1 10 mV VREF LOAD 7 VREF pin = 0 A to - 100 A 1 10 mV VREF IOS 7 VREF pin = 0 V - 14.5 - 10.0 - 7.5 mA VVB 19 4.85 5.00 5.15 V VB LINE 19 VCC pin = 6 V to 25 V 10 100 mV VB LOAD 19 VB pin = 0 A to - 1 mA 10 100 mV VB IOS 19 VB pin = 0 V - 200 - 140 - 100 mA VTLH1 19 VB pin 4.0 4.2 4.4 V VTHL1 19 VB pin 3.4 3.6 3.8 V VH1 19 VB pin 0.6* V VTLH2 7 VREF pin 2.7 2.9 3.1 V VTHL2 7 VREF pin 2.5 2.7 2.9 V Hysteresis width VH2 7 VREF pin 0.2* V Charge current ICS 2, 12 - 7.9 - 5.5 - 4.2 A Soft-start end voltage VCS 2, 12 CTL1, CTL2 pins = 5 V 2.2 2.4 2.6 V Input stability Bias Voltage Block Load stability [VB Reg.] Short-circuit output current Threshold voltage Under voltage Lockout Hysteresis width Protection Circuit Block Threshold voltage [UVLO] Clock Generator Block [OSC] Unit Min Output voltage Soft-start / Soft-stop Block [Soft-Start, Soft-Stop] Value CTL1, CTL2 pins = 5 V, CS1, CS2 pins = 0 V Electrical discharge resistance at soft-stop RDISCG 2, 12 CTL1, CTL2 pins = 0 V, CS1, CS2 pins = 0.5 V 49 70 91 k Soft-stop end voltage VDISCG 2, 12 CTL1, CTL2 pins = 0 V 0.1* V Oscillation frequency fOSC 6 RT pin = 47 k 450 500 550 kHz Oscillation frequency when under voltage is detected fSHORT 6 RT pin = 47 k 62.5 kHz Frequency Temperature variation df/dT 6 Ta = - 30 C to + 85 C 3* % (Continued) DS04-27262-3E 7 MB39A136 (Ta = + 25 C, VCC pin = 15 V, CTL pin = 5 V, VREF pin = 0 A, VB pin = 0 A) Parameter EVTH 3, 11 EVTHT Value Unit Max 0.693 0.700 0.707 V 3, 11 Ta = - 30 C to + 85 C 0.689* 0.700* 0.711* V 3, 11 FB1, FB2 pins = 0 V - 0.1 0 + 0.1 A ISOURCE FB1, FB2 pins = 0 V, 4, 10 COMP1, COMP2 pins = 1V - 390 - 300 - 210 A ISINK FB1, FB2 pins = VREF pin, 4, 10 COMP1, COMP2 pins = 1V 8.4 12.0 16.8 mA Output clamp voltage VILIM 4, 10 FB1, FB2 pins = 0 V, ILIM1, ILIM2 pins = 1.5 V 1.35 1.50 1.65 V ILIM pin input current IILIM 5, 9 FB1, FB2 pins = 0 V, ILIM1, ILIM2 pins = 1.5 V -1 0 +1 A Over-voltage detecting voltage VOVP 3, 11 FB1, FB2 pins 0.776 0.805 0.835 V Over-voltage detection time tOVP 3, 11 49 70 91 s VUVP 3, 11 FB1, FB2 pins 0.450 0.490 0.531 V tUVP 3, 11 512/ fOSC s TOTPH Junction temperature + 160* C TOTPL Junction temperature + 135* C 0* mV IFB Output current Under-voltage Under-voltage detecting Protection voltage Circuit Block [UVP Comp.] Under-voltage detection time Over-temperature Protection Detection Circuit Block temperature [OTP] PFM Control Circuit Block (MODE) Conditions Typ Input current Over-voltage Protection Circuit Block [OVP Comp.] Pin No. Min Threshold voltage Error Amp Block [Error Amp1, Error Amp2] Symbol Synchronous rectification stop voltage VTHLX PFM/PWM mode condition VPFM 13 MODE pin 0 1.4 V Fixed PWM mode condition VPWM 13 MODE pin 2.2 VVREF V MODE pin input current IMODE 13 MODE pin = 0 V -1 0 +1 A 22, 16 LX1, LX2 pins (Continued) 8 DS04-27262-3E MB39A136 (Ta = + 25 C, VCC pin = 15 V, CTL pin = 5 V, VREF pin = 0 A, VB pin = 0 A) Symbol Pin No. High-side output on-resistance RON_MH 23, 15 RON_ML Low-side output on-resistance Parameter Output source current Minimum on time Unit Typ Max DRVH1, DRVH2 pins = - 100 mA 4 7 23, 15 DRVH1, DRVH2 pins = 100 mA 1.0 3.5 RON_SH 21, 17 DRVL1, DRVL2 pins = - 100 mA 4 7 RON_SL 21, 17 DRVL1, DRVL2 pins = 100 mA 0.75 1.70 ISOURCE LX1, LX2 pins = 0 V, CB1, CB2 pins = 5 V 23, 15, DRVH1, DRVH2 pins, 21, 17 DRVL1, DRVL2 pins = 2.5 V Duty 5% - 0.5* A LX1, LX2 pins = 0 V, CB1, CB2 pins = 5 V 23, 15 DRVH1, DRVH2 pins = 2.5 V Duty 5% 0.9* A LX1, LX2 pins = 0 V, CB1, CB2 pins = 5 V 21, 17 DRVL1, DRVL2 pins = 2.5 V Duty 5% 1.2* A 250* ns ISINK tON 23, 15 COMP1, COMP2 pins = 1V Maximum on-duty DMAX 23, 15 FB1, FB2 pins = 0 V 72 80 % Dead time tD 23, 21, LX1, LX2 pins = 0 V, 15, 17 CB1, CB2 pins = 5 V 60 ns 22, 16 VCC pin - LX1, LX2 pins 220* mV Maximum current sense voltage Level Converter Block [LVCNV] Value Min Output Block [DRV] Output sink current Conditions VRANGE Voltage conversion gain ALV 22, 16 5.4 6.8 8.2 V/V Offset voltage at voltage conversion VIO 22, 16 300 mV Slope compensation inclination SLOPE 22, 16 2* V/V 320 420 600 A LX pin input current ILX 22, 16 LX1, LX2 pins = VCC pin (Continued) DS04-27262-3E 9 MB39A136 (Continued) (Ta = + 25 C, VCC pin = 15 V, CTL pin = 5 V, VREF pin = 0 A, VB pin = 0 A) Symbol Pin No. ON condition VON 1, 8 OFF condition VOFF Parameter Value Unit Min Typ Max CTL1, CTL2 pins 2 25 V 1, 8 CTL1, CTL2 pins 0 0.8 V VH 1, 8 CTL1, CTL2 pins 0.4* V ICTLH 1, 8 CTL1, CTL2 pins = 5 V 25 40 A ICTLL 1, 8 CTL1, CTL2 pins = 0 V 0 1 A Standby current ICCS 20 CTL1, CTL2 pins = 0 V 0 10 A Power-supply current ICC 20 LX1, LX2 pins = 0 V, FB1, FB2 pins = 1.0 V, MODE pin = VREF pin 3.3 4.7 mA Control Block Hysteresis [CTL1, CTL2] width Input current General Conditions * : This value is not be specified. This should be used as a reference to support designing the circuits. 10 DS04-27262-3E MB39A136 TYPICAL CHARACTERISTICS * Typical data Power dissipation Power dissipation vs. Operating ambient temperature 2000 Power dissipation PD (mW) 1800 1644 1600 1400 1200 1000 800 600 400 200 0 -50 -25 0 +25 +50 +75 +100 +125 Operating ambient temperature Ta ( C) Error Amp threshold voltage vs. Operating ambient temperature VREF bias voltage VVREF (V) 3.36 3.34 3.32 3.3 3.28 VCC = 15 V fosc = 500 kHz 3.26 3.24 -40 -20 0 +20 +40 +60 +80 +100 Operating ambient temperature Ta ( C) Error Amp threshold voltage EVTH (V) VREF bias voltage vs. Operating ambient temperature 0.71 0.705 CH1 0.7 CH2 VCC = 15 V fosc = 500 kHz 0.695 0.69 -40 -20 0 +20 +40 +60 +80 +100 Operating ambient temperature Ta ( C) (Continued) DS04-27262-3E 11 MB39A136 (Continued) Dead time vs. Operating ambient temperature 90 505 VCC = 15 V 500 495 490 485 480 -20 0 +20 +40 +60 +80 1000 -20 0 +20 +40 +60 +80 +100 6 5.5 VB bias voltage VVB (V) VCC = 15 V Ta = + 25C 10 100 VCC = 6 V 5 4.5 VCC = 5 V 4 3.5 3 VCC = 4.5 V fosc = 500 kHz Ta = + 25C 2.5 100 2 -0.025 1000 -0.02 -0.015 -0.01 -0.005 Timing resistor value RRT (k) VB bias output current IVB (A) Maximum duty cycle vs. Power supply voltage Maximum duty cycle vs. Operating ambient temperature 0 80 80 fosc = 500 kHz Ta = + 25C 79 78 CH2 77 CH1 76 0 10 20 Power supply voltage VVCC (V) 30 Maximum duty cycle DMAX (%) Oscillation frequency fOSC (kHz) tD1 50 Operating ambient temperature Ta( C) tD1 : period from DRVL off to DRVH on tD2 : period from DRVH off to DRVL on VB bias voltage vs. VB bias output current Oscillation frequency vs. Timing resistor value Maximum duty cycle DMAX (%) 60 30 -40 +100 Operating ambient temperature Ta ( C) 12 tD2 70 40 475 -40 75 VCC = 15 V fosc = 500 kHz 80 Dead time tD (ns) Oscillation frequency fOSC (kHz) Oscillation frequency vs. Operating ambient temperature VCC = 15 V fosc = 500 kHz 79 CH2 78 CH1 77 76 75 -40 -20 0 +20 +40 +60 +80 +100 Operating ambient temperature Ta ( C) DS04-27262-3E MB39A136 FUNCTION DESCRIPTION 1. Current Mode It uses the current waveform from the switching (Q1) as a control waveform to control the output voltage, as described below: 1 : The clock (CK) from the internal clock generator (OSC) sets RS-FF and turns on the high-side FET. 2 : Turning on the high-side FET causes the inductor current (IL) rise. Generate Vs that converts this current into the voltage. 3 : The current comparator (I Comp.) compares this Vs with the output (COMP) from the error amplifier (Error Amp) that is negative-feedback from the output voltage (Vo). 4 : When I Comp. detects that Vs exceeds COMP, it resets RS-FF and turns off high-side FET. 5 : The clock (CK) from the clock generator (OSC) turns on the high-side FET again. Thus, switching is repeated. Operate so that the FB electrical potential may become INTREF electrical potential, and stabilize the output voltage as a feedback control. VIN <Error Amp> FB <I Comp.> - + - COMP + INTREF DRVH RS-FF R Q S Drive Logic CK Q1 Current Sense DRVL OSC IL VO Q2 Vs Rs 4 1 5 OSC(CK) IL 3 COMP Vs 2 toff DRVH ton DS04-27262-3E 13 MB39A136 (1) Reference Voltage Block (REF) The reference voltage circuit (REF) generates a temperature-compensated reference voltage (3.3 [V] Typ) using the voltage supplied from the VCC pin. The voltage is used as the reference voltage for the IC's internal circuit. The reference voltage can be used to supply a load current of up to 100 A to an external device through the VREF pin. (2) Bias Voltage Block (VB Reg.) Bias Voltage Block (VB Reg.) generates the reference voltage used for IC's internal circuit, using the voltage supplied from the VCC pin. The reference voltage is a temperature-compensated stable voltage (5 [V] Typ) to supply a current of up to 100 mA through the VB pin. (3) Under Voltage Lockout Protection Circuit Block (UVLO) The circuit protects against IC malfunction and system destruction/deterioration in a transitional state or a momentary drop when a bias voltage (VB) or an internal reference voltage (VREF) starts. It detects a voltage drop at the VB pin or the VREF pin and stops IC operation. When voltages at the VB pin and the VREF pin exceed the threshold voltage of the under voltage lockout protection circuit, the system is restored. (4) Soft-start/Soft-stop Block (Soft-Start, Soft-Stop) Soft-start It protects a rush current or an output voltage (VOx) from overshooting at the output start. Since the lamp voltage generated by charging the capacitor connecting to the CSx pin is used for the reference voltage of the error amplifier (Error Amp), it can set the soft-start time independent of a load of the output (VOx). When the IC starts with "H" level of the CTLx pin, the capacitor at the CSx pin (CS) starts to be charged at 5.5 A. The output voltage (VOx) during the soft-start period rises in proportion to the voltage at the CSx pin generated by charging the capacitor at the CSx pin. During the soft-start with 0.8 V > voltage at CS1 and CS2 pins, operations are as follows: * Fixed PWM operation only (fixed PWM even if MODE pin is set to "L") * Over-voltage protection function and under-voltage protection function are invalid. Soft-stop It discharges electrical charges stored in a smoothing capacitor at output stop. Setting the CTLx pin to "L" level starts the soft-stop function independent of a load of output (Vox). Since the capacitor connecting to the CSx pin starts to discharge through the IC-built-in soft-stop discharging resistance (70 [k] Typ) when the CTLx pin sets at "L" level enters its lamp voltage into the error amplifier (Error Amp), the soft-stop time can be set independent of a load of output (VOx). When discharging causes the voltage at the CSx pin to drop below 100 mV (Typ), the IC shuts down and changes to the stand-by state. In addition, the soft-stop function operates after the under-voltage protection circuit block (UVP Comp.) is latched or after the overtemperature protection circuit block (OTP) detects over-temperature. During the soft-stop with, 0.8 V > voltage at CS1 and CS2 pins, operations are as follows: * Fixed PWM operation only (fixed PWM even if MODE pin is set to "L") * Over-voltage protection function and under-voltage protection function are invalid. (5) Clock Generator Block (OSC) The clock generator has the built-in oscillation frequency setting capacitor and generates a clock that 180phase shifted from each channel by connecting the oscillation frequency setting resistor to the RT pin (Symmetrical-Phase method). 14 DS04-27262-3E MB39A136 (6-1) Error Amp Block (Error Amp1, Error Amp2) The error amplifiers (Error Amp1 and Error Amp2) detect the output voltage from the DC/DC converter and output to the current comparators (I Comp.1 and I Comp.2). The output voltage setting resistor externally connected to FB1 and FB2 pins allows an arbitrary output voltage to be set. In addition, since an external resistor and an external capacitor serially connected between COMP1 and FB1 pins and between COMP2 and FB2 pins allow an arbitrary loop gain to be set, it is possible for the system to compensate a phase stably. (6-2) Over Current Detection (Protection) Block (ILIM) It is the current detection circuit to restrict an output current (IOX). The over current detection block (ILIM) compares an output waveform of the level converter of each channel (see "(12) Level Converter Block (LVCNV)") with the ILIMx pin voltage in every cycle. As a load resistance (ROX) drops, a load current (IOX) increases. Therefore, the output waveform of the level converter exceeds the ILIM pin voltage of each channel. At this time, the output current can be restricted by turning off FET on the high-side and suppressing a peak value of the inductor current. As a result, the output voltage (VOX) should drop. Furthermore, if the output voltage drops and the electrical potential at the FBx pin drops below 0.3 V, the oscillation frequency (fOSC) drops to 1/8. (7) Over-voltage Protection Circuit Block (OVP Comp.) The circuit protects a device connecting to the output when the output voltage (VOx) rises. It compares 1.15 times (Typ) of the internal reference voltage (INTREF) (0.7 V) that is non-inverting-entered into the error amplifier with the feedback voltage that is inverting-entered into the error amplifier and if it detects the state where the latter is higher than the former by 50 s (Typ). It stops the voltage output by setting the RS latch, setting the DRVHx pin to "L" level, setting the DRVLx pin to "H" level, turning off the high-side FETs, and turning on the low-side FETs. The conditions below cancel the protection function: * Setting CTL1 and CTL2 to "L". * Setting the power supply voltage below the UVLO threshold voltage (VTHL1 and VTHL2). (8) Under-voltage Protection Circuit Block (UVP Comp.) It protects a device connecting to the output by stopping the output when the output voltage (VOX) drops. It compares 0.7 times (Typ) of the internal reference voltage (INTREF) (0.7 V) that is non-inverting-entered into the error amplifier with the feedback voltage that is inverting-entered into the error amplifier and if it detects the state where the latter is lower than the former by 512/fosc [s](Typ), it stops the voltage output for both channels by setting the RS latch. The conditions below cancel the protection function: * Setting CTL1 and CTL2 to "L". * Setting the power supply voltage below the UVLO threshold voltage (VTHL1 and VTHL2). (9) Over temperature Protection Circuit Block (OTP) The circuit protects an IC from heat-destruction. If the temperature at the joint part reaches +160 C, the circuit stops the voltage output for both channels by discharging the capacitor connecting to the CSx pin through the soft-stop discharging resistance (70 [k] Typ) in the IC. In addition, if the temperature at the joint part drops to +135 C, the output restarts again through the softstart function. Make sure to design the DC/DC power supply system so that the over temperature protection does not start frequently. DS04-27262-3E 15 MB39A136 (10) PFM Control Circuit Block (MODE) It sets the control mode of the IC and makes control at automatic PFM/PWM switching. MODE pin connection Control mode Features Automatic PFM/PWM Highly-efficient at light load switching "L" (GND) "H" (VREF) Stable oscillation frequency Stable switching ripple voltage Excellent in rapid load change characteristic at heavy load to light load Fixed PWM Automatic PFM/PWM switching mode operation It compares the LX1 pin and the LX2 pin voltages with GND electrical potential at Di Comp. In the comparison, the negative voltage at the LX pin causes the low-side FET to set on, positive voltage causes it to set off (Di Comp. method) . As a result, the method restricts the back flow of the inductor current at a light load and makes the switching of the inductor current discontinuous (DCM) . Such an operation allows the oscillation frequency to drop, resulting in high efficiency at a light load. (11) Output Block (DRV) The output circuit is configured in CMOS type for both of the high-side and the low-side, allowing the external N-ch MOS FET to drive. (12) Level Converter Block (LVCNV) The circuit detects and converts the current when the high-side FET turns on. It converts the voltage waveform between drain side (VCC pin voltage) and the source side (LX1 and LX2 pin voltage) on the high-side FET into the voltage waveform for GND reference. Note: x : Each channel number (13) Control Block (CTL1, CTL2) The circuit controls on/off of the output from the IC. Control function table DC/DC converter CTL1 CTL2 (VO1) 16 DC/DC converter (VO2) Remarks L L OFF OFF Standby H L ON OFF L H OFF ON H H ON ON DS04-27262-3E MB39A136 PROTECTION FUNCTION TABLE The following table shows the state of each pin when each protection function operates. Output of each pin after detection DC/DC output Detection Protection Function dropping operacondition VREF VB DRVHx DRVLx tion Under Voltage Lock Out Protection (UVLO) VB < 3.6 V VREF < 2.7 V < 2.7 V < 3.6 V L L Self-discharge by load Under Voltage Protection (UVP) FBx < 0.49 V 3.3 V 5V L L Electrical discharge by soft-stop function Over Voltage Protection (OVP) FBx > 0.805 V 3.3 V 5V L H 0 V clamping Over Current Protection (ILIM) The output voltage is dropping to keep switching switching constant output current. COMPx > ILIMx 3.3 V 5V Over Temperature Protection (OTP) Tj > + 160 C 3.3 V 5V L L CONTROL (CTL) CTLx : HL (CSx > 0.1 V) 3.3 V 5V L L Electrical discharge by soft-stop function Note: x is the each channel number DS04-27262-3E 17 MB39A136 I/O PIN EQUIVALENT CIRCUIT DIAGRAM VREF pin CTL1, CTL2 pins VCC VB CTL1,CTL2 VREF ESD protection element GND GND VB pin CS1, CS2 pins VCC VREF VB CS1,CS2 GND FB1, FB2 pins VREF GND COMP1, COMP2 pins VREF FB1,FB2 COMP1, COMP2 GND GND (Continued) 18 DS04-27262-3E MB39A136 (Continued) ILM1, ILM2 pins RT pin VREF VREF VB ILIM1,ILIM2 ILIM1,ILIM2 RT GND GND GND MODE pin CB1, CB2, DRVH1, DRVH2, LX1, LX2 pins CB1,CB2 CB1,CB2 VREF VREF VREF DRVH1, DRVH1, DRVH2 DRVH2 MODE LX1,LX2 LX1,LX2 GND DRVL1, DRVL2 pins GND GND VB DRVL1,DRVL2 GND DS04-27262-3E 19 MB39A136 EXAMPLE APPLICATION CIRCUIT R21 VREF VIN (4.5 V to 25 V) MODE C13 VCC RT 13 6 20 MB39A136 19 CS1 2 A VB <CH1> C7 A D2 COMP1 4 R8-1 R8-2 24 CB1 FB1 23 3 22 R9 R11 ILIM1 5 21 VO1 L1 C5 R23 C9 Q1 DRVH1 LX1 Q1 DRVL1 C2-1 C2-2 C2-3 C1 R12 C14 CS2 B 12 <CH2> 14 C8 15 COMP2 R14-1 R14-2 C11 10 16 R25 FB2 11 17 R15 R17 B D2 CB2 Q2 VO2 C6 DRVH2 LX2 DRVL2 Q2 C3-1 C3-2 ILIM2 L2 C4-1 C4-2 C4-3 9 1 CTL1 8 CTL2 R18 7 VREF 18 GND C15 20 DS04-27262-3E MB39A136 PARTS LIST Component Item Specification Vendor Package Q1 N-ch FET VDS = 30 V, ID = 8 A, Ron = 21 m RENESAS SO-8 PA2755 Dual type (2 elements) Q2 N-ch FET VDS = 30 V, ID = 8 A, Ron = 21 m RENESAS SO-8 PA2755 Dual type (2 elements) D2 Diode VF = 0.35 V at IF = 0.2 A ON Semi L1 Inductor 1.5 H (6.2 m, 8.9 A) TDK VLF10040T-1R5N L2 Inductor 3.3 H (9.7 m, 6.9 A) TDK VLF10045T-3R3N C1 Ceramic capacitor 22 F (25 V) TDK 3225 C3225JC1E226M C2-1 C2-2 C2-3 Ceramic capacitor Ceramic capacitor Ceramic capacitor 22 F (10 V) 22 F (10 V) 22 F (10 V) TDK TDK TDK 3216 3216 3216 C3216JB1A226M C3216JB1A226M C3216JB1A226M 3 capacitors in parallel C3-1 C3-2 Ceramic capacitor Ceramic capacitor 22 F (25 V) 22 F (25 V) TDK TDK 3225 3225 C3225JC1E226M C3225JC1E226M 2 capacitors in parallel C4-1 C4-2 C4-3 Ceramic capacitor Ceramic capacitor Ceramic capacitor 22 F (10 V) 22 F (10 V) 22 F (10 V) TDK TDK TDK 3216 3216 3216 C3216JB1A226M C3216JB1A226M C3216JB1A226M 3 capacitors in parallel C5 Ceramic capacitor 0.1 F (50 V) TDK 1608 C1608JB1H104K C6 Ceramic capacitor 0.1 F (50 V) TDK 1608 C1608JB1H104K C7 Ceramic capacitor 0.022 F (50 V) TDK 1608 C1608JB1H223K C8 Ceramic capacitor 0.022 F (50 V) TDK 1608 C1608JB1H223K C9 Ceramic capacitor 820 pF (50 V) TDK 1608 C1608CH1H821J C11 Ceramic capacitor 1000 pF (50 V) TDK 1608 C1608CH1H102J C13 Ceramic capacitor 0.01 F (50 V) TDK 1608 C1608JB1H103K C14 Ceramic capacitor 2.2 F (16 V) TDK 1608 C1608JB1C225K C15 Ceramic capacitor 0.1 F (50 V) TDK 1608 C1608JB1H104K R8-1 R8-2 Resistor 1.6 k 9.1 k SSM SSM 1608 1608 RR0816P162D RR0816P912D R9 Resistor 15 k SSM 1608 RR0816P153D R11 Resistor 56 k SSM 1608 RR0816P563D R12 Resistor 47 k SSM 1608 RR0816P473D R14-1 R14-2 Resistor 1.8 k 39 k SSM SSM 1608 1608 RR0816P182D RR0816P393D R15 Resistor 11 k SSM 1608 RR0816P113D Parts Name SOT-323 BAT54AWT1 Remark Dual type 2 capacitors in series 2 capacitors in series (Continued) DS04-27262-3E 21 MB39A136 (Continued) Component Item Specification Vendor Package R17 Resistor 56 k SSM 1608 RR0816P563D R18 Resistor 56 k SSM 1608 RR0816P563D R21 Resistor 82 k SSM 1608 RR0816P823D R23 Resistor 22 k SSM 1608 RR0816P223D R25 Resistor 56 k SSM 1608 RR0816P563D RENESAS ON Semi TDK SSM 22 Parts Name Remark : Renesas Electronics Corporation : ON Semiconductor : TDK Corporation : SUSUMU Co.,Ltd. DS04-27262-3E MB39A136 APPLICATION NOTE Setting method for PFM/PWM and fixed PWM modes For the setting method for each mode, see" FUNCTION DESCRIPTION (10) PFM Control Circuit Block (MODE)". Cautions at PFM/PWM mode If a load current drops rapidly because of rapid load change and others, it tends to take a lot of time to restore overshooting of an output voltage. As a result, the over-voltage protection may operate. In this case, solution are possible by the addition of the load resistance of value to be able to restore the output voltage in the over-voltage detection time. Setting method of output voltage Set it by adjusting the output voltage setting zero-power resistance ratio. R1 + R2 R2 VO = VO R1, R2 x 0.7 : Output setting voltage [V] : Output setting resistor value [] VO R1 FB1 FB2 R2 Make sure that the setting does not exceed the maximum on-duty. Calculate the on-duty by the following formula: DMAX_Min = VO + RON_Sync x IOMAX VIN - RON_Main x IOMAX + RON_Sync x IOMAX DMAX_Min VIN VO RON_Main RON_Sync IOMAX DS04-27262-3E : Minimum value of the maximum on-duty cycle : Power supply voltage of switching system [V] : Output setting voltage [V] : High-side FET ON resistance [] : Low-side FET ON resistance [] : Maximum load current[A] 23 MB39A136 Oscillation frequency setting method Set it by adjusting the RT pin resistor value. fOSC = 1.09 RRT x 40 x 10 - 12 + 300 x 10 - 9 RRT fOSC : RT resistor value [] : Oscillation frequency [Hz] The oscillation frequency must set for on-time (tON) to become 300ns or more. Calculate the on-time by the following formula. tON = VO VIN x fOSC tON VIN VO fOSC 24 : On-time [s] : Power supply voltage of switching system [V] : Output setting voltage [V] : Oscillation frequency [Hz] DS04-27262-3E MB39A136 Setting method of soft-start time Calculate the soft-start time by the following formula. tS = 1.4 x 105 x CCS ts CCS : Soft-start time[s] (Time to becoming output 100%) : CS pin capacitor value [F] Calculate delay time until the soft-start beginning by the following formula. td1 = 30 x CVB + 290 x CVREF + 1.455 x 104 x CCS td1 CCS CVB CVREF : Delay time including VB voltage and VREF voltage starts [s] : CS pin capacitor value [F] : VB pin capacitor value [F] : VREF pin capacitor value [F] (0.1 [F] Typ) Calculate delay time for starting while one channel has already started (UVLO released : VB, VREF output before) by the following formula. td2 = 1.455 x 104 x CCS : Delay time for starting while one channel has already started [s] td2 : CS pin capacitor value [F] CCS Calculate the discharge time at the soft-stop by the following formula. tdis = 1.44 x 105 x CCS : Discharge time [s] tdis : CS pin capacitor value [F] CCS In addition, calculate the delay time to the discharge starting by the following formula. td3 = 7.87 x 104 x CCS : Delay time until discharge start [s] td3 : CS pin capacitor value [F] CCS ts tdis CTL1 CTL2 VO1 VO2 td1 DS04-27262-3E td2 td3 25 MB39A136 * Simultaneous operation of plural channels Soft-start/soft-stop operation according to the same timing as two channels can be achieved by even connecting it as shown in the figure below at the power supply on/off. <Connection example 1> When you adjust the soft-start time Make the CS capacitor common. Connect CTL1 and CTL2. Note: In this case, the soft-start time (ts), the discharge time (tdis), and the delay time (td1, td2, td3) decrease in the half value of compared with when CS capacitor is connected to each channel. DC/DC 1 : Vo = 1.2 V setting CS1 V < DC/DC 2 > 1.8 V MB39A136 < DC/DC 1 > Vo 1.2 V CTL CTL1 CTL2 CS2 CS capacitor CTL t DC/DC 2 : Vo = 1.8 V setting 26 DS04-27262-3E MB39A136 Setting method of over current detection value It is possible to set over-current detection value (ILIM) by adjusting the over-current detection setting resistor value ratio. Calculate the over current detection setting resistor value by the following formula. 3.3 x R2 - 0.3 R1 + R2 6.8 x RON ILIM = + VIN - VO L x (200 x 10 - 9 - VO 2 x fOSC x VIN ) 200 x 103 R1 + R2 30 x 103 ILIM R1, R2 L VIN VO fOSC RON * : Over current detection value [A] : ILIM setting resistor value []* : Inductor value [H] : Power supply voltage of switching system [V] : Output setting voltage [V] : Oscillation frequency [Hz] : High-side FET ON resistance [] Since the over current detection value depends on the on-resistance of FET, the over current detection setting resistor value ratio should be adjusted in consideration of the temperature characteristics of the onresistance. When the temperature at the FET joint part rises by + 100 C, the on-resistance of FET increases to about 1.5 times. Inductor current VREF Over-current detection value ILIM R1 IO ILIM* R2 0 * Time If the over current detection function is not used, connect the ILIM pin (ILIM1 and ILIM2) to the VREF pin. DS04-27262-3E 27 MB39A136 Selection of smoothing inductor The inductor value selects the value that the ripple current peak-to-peak value becomes 50% or less of the maximum load current as a rough standard. Calculate the inductor value in this case by the following formula. VO VIN - VO x L LOR x IOMAX VIN x fOSC L IOMAX LOR VIN VO fOSC : Inductor value [H] : Maximum load current [A] : Ripple current peak-to-peak value of Maximum load current ratio (=0.5) : Power supply voltage of switching system [V] : Output setting voltage [V] : Oscillation frequency [Hz] An inductor ripple current value limited on the principle of operation is necessary for this device. However, when it uses the high-side FET of the low Ron resistance, the switching ripple voltage become small, and the inductor ripple current value may become insufficient. This should be solved by the oscillation frequency or reducing the inductor value. Select the one of the inductor value that meets a requirement listed below. VO VIN - VO x x RON L VRON VIN x fOSC L VIN VO fOSC VRON RON : Inductor value [H] : Power supply voltage of switching system [V] : Output setting voltage [V] : Oscillation frequency [Hz] : Ripple voltage [V] (20 mV or more is recommended) : High-side FET ON resistance [] It is necessary to calculate the maximum current value that flows to the inductor to judge whether the electric current that flows to the inductor is a rated value or less. Calculate the maximum current value of the inductor by the following formula. IL VIN - VO VO ILMAX IoMAX + , IL = x 2 L VIN x fOSC ILMAX IoMAX IL L VIN VO fOSC : Maximum current value of inductor [A] : Maximum load current [A] : Ripple current peak-to-peak value of inductor [A] : Inductor value [H] : Power supply voltage of switching system [V] : Output setting voltage [V] : Oscillation frequency [Hz] Inductor current ILMAX IoMAX IL t 0 28 DS04-27262-3E MB39A136 Selection of SWFET The switching ripple voltage generated between drain and sources on high-side FET is necessary for this device operation. Select the one of the SWFET of on-resistance that satisfies the following formula. RON_Main VRON_Main , RON_Main IL RON_Main IL VRON_Main ILIM VRONMAX VRONMAX IL ILIM + 2 : High-side FET ON resistance [] : Ripple current peak-to-peak value of inductor [A] : High-side FET ripple voltage [V] (20mV or more is recommended) : Over current detection value [A] : Maximum current sense voltage [V] (240mV or less is recommended) Select FET ratings with a margin enough for the input voltage and the load current. Ratings with the overcurrent detection setting value or more are recommended. Calculate a necessary rated value of high-side FET and low-side FET by the following formula. ID > IoMAX + ID IoMAX IL IL 2 : Rated drain current [A] : Maximum load current [A] : Ripple current peak-to-peak value of inductor [A] VDS > VIN VDS VIN : Rated voltage between drain and source [V] : Power supply voltage of switching system [V] VGS > VB VGS VB : Rated voltage between gate and source [V] : VB voltage [V] Moreover, it is necessary to calculate the loss of SWFET to judge whether a permissible loss of SWFET is a rated value or less. Calculate the loss on high-side FET by the following formula. PMainFET = PRON_Main + PSW_Main PMainFET : High-side FET loss [W] PRON_Main : High-side FET conduction loss [W] PSW_Main : High-side FET SW loss [W] DS04-27262-3E 29 MB39A136 High-side FET conduction loss PRON_Main = IoMAX2 x PRON_Main IOMAX VIN VO RON_Main VO VIN x RON_Main : High-side FET conduction loss [W] : Maximum load current [A] : Power supply voltage of switching system [V] : Output voltage [V] : High-side FET ON resistance [] High-side FET SW loss PSW_Main = PSW_Main VIN fOSC Ibtm Itop tr tf VIN x fOSC x (Ibtm x tr + Itop x tf) 2 : High-side FET SW loss [W] : Power supply voltage of switching system [V] : Oscillation frequency [Hz] : Ripple current bottom value of inductor [A] : Ripple current top value of inductor [A] : Turn-on time on high-side FET [s] : Turn-off time on high-side FET[s] Calculate the Ibtm, the Itop, the tr and the tf simply by the following formula. Ibtm = IOMAX - Itop = IOMAX + tr = IL 2 Qgd x 4 5 - Vgs (on) IOMAX IL Qgd Vgs (on) 30 IL 2 tf = Qgd x 1 Vgs (on) : Maximum load current [A] : Ripple current peak-to-peak value of inductor [A] : Quantity of charge between gate and drain on high-side FET [C] : Voltage between gate and source in Qgd on high-side FET [V] DS04-27262-3E MB39A136 Calculate the loss on low-side FET by the following formula. PSyncFET = PRon_Sync* = IoMAX2 x (1 - PSyncFET PRon_Sync IOMAX VIN VO Ron_Sync VO ) x Ron_Sync VIN : Low-side FET loss [W] : Low-side FET conduction loss [W] : Maximum load current [A] : Power supply voltage of switching system [V] : Output voltage [V] : Low-side FET on-resistance [] * : The transition voltage of the voltage between drain and source on low-side FET is generally small, and the switching loss is omitted here for the small one as it is possible to disregard it. The gate drive power of SWFET is supplied by LDO in IC, therefore all SWFET allowable maximum total charge (QgTotalMax) of 2ch is determined by the following formula. 0.095 fOSC QgTotalMax QgTotalMax fOSC : SWFET allowable maximum total charge [C] : Oscillation frequency [Hz] Selection of fly-back diode When the conversion efficiency is valued, the improved property of the conversion efficiency is possible by the addition of the fly-back diode. Thought it is usually unnecessary. The effect is achieved in the condition where the oscillation frequency is high or output voltage is lower. Select schottky barrier diode (SBD) that the forward current is as small as possible. In this DC/DC control IC, the period for the electric current flows to fly back diode is limited to synchronous rectification period (60 ns x 2) because of using the synchronous rectification method. Therefore, select the one that the electric current of fly back diode doesn't exceed ratings of forward current surge peak (IFSM).Calculate the forward current surge peak ratings of fly back diode by the following formula. IFSM IoMAX + IFSM IoMAX IL IL 2 : Forward current surge peak ratings of fly back diode [A] : Maximum load current [A] : Ripple current peak-to-peak value of inductor [A] Calculate ratings of the fly-back diode by the following formula: VR_Fly > VIN VR_Fly VIN DS04-27262-3E : Reverse voltage of fly-back diode direct current [V] : Power supply voltage of switching system [V] 31 MB39A136 Selection of output capacitor This device supports a small ceramic capacitor of the ESR. The ceramic capacitor that is low ESR is an ideal to reduce the ripple voltage compared with other capacitor. Use the tantalum capacitor and the polymer capacitor of the low ESR when a mass capacitor is needed as the ceramic capacitor can not support. To the output voltage, the ripple voltage by the switching operation of DC/DC is generated. Discuss the lower bound of output capacitor value according to an allowable ripple voltage. Calculate the output ripple voltage from the following formula. VO = ( 1 + ESR) x IL 2 x fOSC x CO VO ESR IL CO fOSC : Switching ripple voltage [V] : Series resistance component of output capacitor [] : Ripple current peak-to-peak value of inductor [A] : Output capacitor value [F] : Oscillation frequency [Hz] Notes: * The ripple voltage can be reduced by raising the oscillation frequency and the inductor value besides capacitor. * Capacitor has frequency characteristic, the temperature characteristic, and the electrode bias characteristic, etc. The effective capacitor value might become extremely small depending on the condition. Note the effective capacitor value in the condition. Calculate ratings of the output capacitor by the following formula: VCO > VO VCO VO : Withstand voltage of the output capacitor [V] : Output voltage [V] Note: Select the capacitor rating with withstand voltage allowing a margin enough for the output voltage. In addition, use the allowable ripple current with an enough margin, if it has a rating. Calculate an allowable ripple current of the output capacitor by the following formula: Irms IL 23 Irms IL 32 : Allowable ripple current (effective value) [A] : Ripple current peak-to-peak value of inductor [A] DS04-27262-3E MB39A136 Selection of input capacitor Select the input capacitor whose ESR is as small as possible. The ceramic capacitor is an ideal. Use the tantalum capacitor and the polymer capacitor of the low ESR when a mass capacitor is needed as the ceramic capacitor can not support. To the power supply voltage, the ripple voltage by the switching operation of DC/DC is generated. Discuss the lower bound of input capacitor according to an allowable ripple voltage. Calculate the ripple voltage of the power supply from the following formula. IOMAX CIN VIN = VIN IOMAX CIN VIN VO fOSC ESR IL x VO VIN x fOSC + ESR x (IOMAX + IL 2 ) : Switching system power supply ripple voltage peak-to-peak value [V] : Maximum load current value [A] : Input capacitor value [F] : Power supply voltage of switching system [V] : Output setting voltage [V] : Oscillation frequency [Hz] : Series resistance component of input capacitor [] : Ripple current peak-to-peak value of inductor [A] Notes: * The ripple voltage of the power supply can be reduced by raising the oscillation frequency besides capacitor. * Capacitor has frequency characteristic, the temperature characteristic, and the electrode bias characteristic, etc. The effective capacitor value might become extremely small depending on the condition. Note the effective capacitor value in the condition. Calculate ratings of the input capacitor by the following formula: VCIN > VIN VCIN VIN : Withstand voltage of the input capacitor [V] : Power supply voltage of switching system [V] Note: Select the capacitor rating with withstand voltage with margin enough for the input voltage. In addition, use the allowable ripple current with an enough margin, if it has a rating. Calculate an allowable ripple current by the following formula: Irms IOMAX x Irms IOMAX VIN VO DS04-27262-3E VO x (VIN - VO) VIN : Allowable ripple current (effective value) [A] : Maximum load current value [A] : Power supply voltage of switching system [V] : Output voltage [V] 33 MB39A136 Selection of boot strap diode Select Schottky barrier diode (SBD), that forward current is as small as possible. The electric current that drives the gate of high-side FET flows to SBD of the bootstrap circuit. Calculate the mean current by the following formula. Select it so as not to exceed the electric current ratings. ID Qg x fOSC ID Qg fOSC : Forward current [A] : Total quantity of charge of gate on high-side FET [C] : Oscillation frequency [Hz] Calculate ratings of the boot strap diode by the following formula: VR_BOOT > VIN VR_BOOT VIN : Reverse voltage of boot strap diode direct current [V] : Power supply voltage of switching system [V] Selection of boot strap capacitor To drive the gate of high-side FET, the bootstrap capacitor must have enough stored charge. Therefore, a minimum value as a target is assumed the capacitor which can store electric charge 10 times that of the Qg on high-side FET. And select the boot strap capacitor. CBOOT 10 x CBOOT Qg VB Qg VB : Boot strap capacitor [F] : Amount of gate charge on high-side FET [C] : VB voltage [V] Calculate ratings of the boot strap capacitor by the following formula: VCBOOT > VB VCBOOT VB 34 : Withstand voltage of the boot strap capacitor [V] : VB voltage [V] DS04-27262-3E MB39A136 Design of phase compensation circuit Assume the phase compensation circuit of 1pole-1zero to be a standard in this device. 1pole-1zero phase compensation circuit VO Rc R1 FB Cc + To I Comp. COMP R2 INTREF Error Amp As for crossover frequency (fCO) that shows the band width of the control loop of DC/DC. The higher it is, the more excellent the rapid response becomes, however, the possibility of causing the oscillation due to phase margin shortage increases. Though this crossover frequency (fCO) can be arbitrarily set, make 1/10 of the oscillation frequencies (fosc) a standard, and set it to the upper limit. Moreover, set the phase margin at least to 30 C, and 45 C or more if possible as a reference. Set the constants of Rc and Cc of the phase compensation circuit using the following formula as a target. RC = CC = DS04-27262-3E (VIN - VO) ALVCNV x RON_Main x fCO x 2 x CO x VO VIN x fOSC x L x IOMAX x R1 CO x VO RC x IOMAX RC CC VIN VO fOSC IOMAX L CO RON_Main R1 ALVCNV : Phase compensation resistor value [] : Phase compensation capacitor value [F] : Power supply voltage of switching system [V] : Output setting voltage [V] : Oscillation frequency [Hz] : Maximum load current value [A] : Inductor value [H] : Output capacitor value [F] : High-side FET ON resistance[] : Output setting resistor value [] fCO : Cross-over frequency (arbitrary setting) [Hz] : Level converter voltage gain [V/V] On-duty 50% : ALVCNV = 6.8 On-duty > 50% : ALVCNV = 13.6 35 MB39A136 VB pin capacitor 2.2 F is assumed to be a standard, and when Qg of SWFET used is large, it is necessary to adjust it. To drive the gate of high-side FET, the bootstrap capacitor must have enough stored charge. Therefore, a minimum value as a target is assumed the capacitor, which can store electric charge 100 times that of the Qg of the SWFET. And select it. CVB 100 x CVB Qg VB Qg VB : VB pin capacitor value [F] : Total amount of gate charge of 2 ch respectively: high-side FET and low-side FET [C] : VB voltage [V] Calculate ratings of the VB pin capacitor by the following formula: VCVB > VB VCVB VB 36 : Withstand voltage of the VB pin capacitor [V] : VB voltage [V] DS04-27262-3E MB39A136 VB regulator In the condition for which the potential difference between VCC and VB is insufficient, the decrease in the voltage of VB happens because of power output on-resistance and load current (mean current of all external FET gate driving current and load current of internal IC) of the VB regulator. Stop the switching operation when the voltage of VB decreases and it reaches threshold voltage (VTHL1) of the under voltage lockout protection circuit. Therefore, set oscillation frequency or external FET or I/O potential difference of the VB regulator using the following formula as a target when you use this IC. VCC VB (VTHL1) + (Qg x fOSC + ICC) x RVB VCC : Power supply voltage [V] (VIN) : Threshold voltage of VB under-voltage lockout protection circuit [V] VB (VTHL1) (3.8 [V] Max ) : Total amount of gate charge of 2 ch respectively: high-side FET and low-side FET Qg [C] fOSC : Oscillation frequency [Hz] ICC : Power supply current [A] (4.7 x 10-3[A] =: Load current of VB (LDO) ) RVB : VB output on-resistance [] (100 (The reference value at VCC = 4.5 V) ) If the I/O potential difference is small, the problem can be solved by connecting the VB pin and the VCC pin. The conditions of the input voltage range are as follows: VIN input voltage ranges: 4.5 V 25 V 6.0 V (1) (3) (1) For 4.5 V < VIN < 6.0 V Connect VB pin to VCC. (2) When the input voltage range steps over 6.0 V Normal use (VCC to VB not connected) (3) For 6.0 V VIN Normal use (VCC to VB not connected) (2) Note that if the I/O potential difference is not enough when used, use the actual machine to check carefully the operations at the normal operation, start operation, and stop operation. In particular, care is needed when the input voltage range over 6 V. DS04-27262-3E 37 MB39A136 Power dissipation and the thermal design As for this IC, considerations of the power dissipation and thermal design are not necessary in most cases because of its high efficiency. However, they are necessary for the use at the conditions of a high power supply voltage, a high oscillation frequency, high load, and the high temperature. Calculate IC internal loss (PIC) by the following formula. PIC = VCC x (ICC + Qg x fOSC) PIC VCC ICC Qg fOSC : IC internal loss [W] : Power supply voltage (VIN) [V] : Power supply current [A] (4.7 [mA] Max) : All SWFET total quantity of charge for ch 2 [C] (Total with Vgs = 5 V) : Oscillation frequency[Hz] Calculate junction temperature (Tj) by the following formula. Tj = Ta + ja x PIC Tj Ta ja PIC : Junction temperature [ C] (+150 [ C] Max) : Ambient temperature [ C] : TSSOP-24 Package thermal resistance (76 C/W) : IC internal loss [W] Handling of the pins when using a single channel Although this device is a 2-channel DC/DC converter control IC, it is also able to be used as a 1-channel DC/DC converter by handling the pins of the unused channel as shown in the following diagram. CBx COMPx "Open" FBx DRVHx "Open" DRVLx "Open" CSx CTLx LXx ILIMx Note: x is the unused channel number. 38 DS04-27262-3E MB39A136 Board layout Consider the points listed below and do the layout design. * Provide the ground plane as much as possible on the IC mounted face. Connect bypass capacitor connected with the VCC and VB pins, and GND pin of the switching system parts with switching system GND (PGND). Connect other GND connection pins with control system GND (AGND), and separate each GND, and try not to pass the heavy current path through the control system GND (AGND) as much as possible. In that case, connect control system GND (AGND) and switching system GND (PGND) right under IC. * Connect the switching system parts as much as possible on the surface. Avoid the connection through the through-hole as much as possible. * As for GND pins of the switching system parts, provide the through hole at the proximal place, and connect it with GND of internal layer. * Pay the most attention to the loop composed of input capacitor (CIN), SWFET, and fly-back diode (SBD). Consider making the current loop as small as possible. * Place the boot strap capacitor (CBOOT1, CBOOT2) proximal to CBx and LXx pins of IC as much as possible. * This device monitors the voltage between drain and source on high-side FET as voltage between VCC and LX pins. Place the input capacitor (CIN) and the high-side FET of each CH proximally as much as possible. Draw out the wiring to VCC pin from the proximal place to the input capacitor of CH1 and CH2. As for the net of the LXx pin, draw it out from the proximal place to the source pin on high-side FET. Moreover, a large electric current flows momentary in the net of the LXx pin. Wire the linewidth of about 0.8mm to be a standard, as short as possible. * Large electric current flows momentary in the net of DRVHx and DRVLx pins connected with the gate of SWFET. Wire the linewidth of about 0.8mm to be a standard, as short as possible. * By-pass capacitor (CVCC, CVREF, CVB) connected with VREF, VCC, and VB, and the resistor (RRT) connected with the RT pin should be placed close to the pin as much as possible. Also connect the GND pin of the by-pass capacitor with GND of internal layer in the proximal through-hole. * Consider the net connected with RT, FBx, and the COMPx pins to keep away from a Switching system parts as much as possible because it is sensitive to the noise. Moreover, place the output voltage setting resistor and the phase compensation circuit element connected with this net close to the IC as much as possible, and try to make the net as short as possible. In addition, for the internal layer right under the installing part, provide the control system GND (AGND) of few ripple and few spike noises, or provide the ground plane of the power supply voltage as much as possible. Switching system parts : Input capacitor (CIN), SWFET, Fly-back diode (SBD), Inductor (L), Output capacitor (CO) Note: x : Each channel number Layout example of switching components Layout example of IC To the VCC pin High-side FET CBOOT1 1pin Through-hole High-side FET CVCC AGND VIN Through-hole RRT CIN To the LX1 pin PGND To the LX2 pin Low-side FET Low-side FET PGND CVB CVREF CIN SBD (option) SBD (option) CO CBOOT2 PGND AGND CO L L Vo1 Vo2 AGND and PGND are connected right under IC. Surface Internal layer DS04-27262-3E Output voltage Vo1 feedback Output voltage Vo2 feedback 39 MB39A136 REFERENCE DATA CH1 Conversion Efficiency CH2 Conversion Efficiency Conversion Efficiency vs. Load Current Conversion Efficiency vs. Load Current 100 CH1 VIN = 12 V VO1 = 1.2 V fosc = 300 kHz Ta = + 25C 95 90 85 Conversion Efficiency (%) Conversion Efficiency (%) 100 80 PFM/PWM 75 70 Fixed PWM 65 60 0.01 0.1 1 CH2 VIN = 12 V VO2 = 3.3 V fosc = 300 kHz Ta = + 25C 95 90 85 PFM/PWM 80 75 Fixed PWM 70 65 60 0.01 10 Load Current IO1(A) 1 10 Load Current IO2 (A) CH1 Load Regulation Output Voltage vs. Load Current CH2 Load Regulation Output Voltage vs. Load Current 1.30 3.60 VIN = 12 V VO1 = 1.2 V MODE = VREF fosc = 300 kHz Ta = + 25C 1.26 1.24 VIN = 12 V VO2 = 3.3 V MODE = VREF fosc = 300 kHz Ta = + 25C 3.50 Output Voltage VO2(V) 1.28 Output Voltage VO1 (V) 0.1 1.22 1.20 1.18 1.16 1.14 3.40 3.30 3.20 3.10 1.12 1.10 3.00 0 1 2 3 Load Current IO1(A) 4 5 0 1 2 3 4 5 Load Current IO2 (A) (Continued) 40 DS04-27262-3E MB39A136 (Continued) CH1 Load Sudden Change Waveform IO1 : 1 A/div 2A CH2 Load Sudden Change Waveform IO2 : 1 A/div 2A 0A 0A 100 s/div 100 s/div VO1 : 200 mV/div (1.2 V offset) VIN = 12 V, VO1 = 1.2 V IO1 = 02 A, fOSC = 300 kHz, Ta = + 25 C VO2 : 200 mV/div (3.3 V offset) VIN = 12 V, VO2 = 3.3 V IO2 = 02 A, fOSC = 300 kHz, Ta = + 25 C CTL Startup Waveform CTL Stop Waveform CTL1, 2 : 5 V/div CTL1, 2 : 5 V/div VO2: 1 V/div VO2: 1 V/div VO1: 1 V/div VO1: 1 V/div 1 ms/div 1 ms/div VIN = 12 V, fOSC = 300 kHz, Ta = + 25 C, Soft-start setting time = 3.0 ms VO1 = 1.2 V, IO1 = 5 A (0.24 ) , VO2 = 3.3 V, IO2 = 5 A (0.66 ) Normal operation Over current protection Under voltage protection operation waveform VO1 : 0.5 V/div 1 CS1 : 2 V/div VIN = 12 V VO1 = 1.2 V fOSC = 300 kHz Ta = + 25 C 2 LX1 : 10 V/div 3 IO1 : 10 A/div 4 500 s/div Normal operation DS04-27262-3E Over current protection operation Under voltage protection operation 41 MB39A136 USAGE PRECAUTION 1. Do not configure the IC over the maximum ratings. If the IC is used over the maximum ratings, the LSI may be permanently damaged. It is preferable for the device to be normally operated within the recommended usage conditions. Usage outside of these conditions can have an adverse effect on the reliability of the LSI. 2. Use the device within the recommended operating conditions. The recommended values guarantee the normal LSI operation under the recommended operating conditions. The electrical ratings are guaranteed when the device is used within the recommended operating conditions and under the conditions stated for each item. 3. Printed circuit board ground lines should be set up with consideration for common impedance. 4. Take appropriate measures against static electricity. * Containers for semiconductor materials should have anti-static protection or be made of conductive material. * After mounting, printed circuit boards should be stored and shipped in conductive bags or containers. * Work platforms, tools, and instruments should be properly grounded. * Working personnel should be grounded with resistance of 250 k to 1 M in series between body and ground. 5. Do not apply negative voltages. The use of negative voltages below - 0.3 V may make the parasitic transistor activated, and can cause malfunctions. 42 DS04-27262-3E MB39A136 ORDERING INFORMATION Part number Package MB39A136PFT 24-pin plastic TSSOP (FPT-24P-M09) Remarks EV BOARD ORDERING INFORMATION Part number EV board version No. Remarks MB39A136EVB-01 MB39A136EVB-01 Rev2.0 TSSOP-24 DS04-27262-3E 43 MB39A136 RoHS COMPLIANCE INFORMATION OF LEAD (Pb) FREE VERSION The LSI products of FUJITSU SEMICONDUCTOR with "E1" are compliant with RoHS Directive, and has observed the standard of lead, cadmium, mercury, Hexavalent chromium, polybrominated biphenyls (PBB), and polybrominated diphenyl ethers (PBDE). A product whose part number has trailing characters "E1" is RoHS compliant. MARKING FORMAT (Lead Free version) 39A136 XXXX E1 XXX INDEX 44 Lead Free version DS04-27262-3E MB39A136 LABELING SAMPLE (Lead free version) Lead free mark JEITA logo MB123456P - 789 - GE1 (3N) 1MB123456P-789-GE1 1000 (3N)2 1561190005 107210 JEDEC logo G Pb QC PASS PCS 1,000 MB123456P - 789 - GE1 2006/03/01 ASSEMBLED IN JAPAN MB123456P - 789 - GE1 1/1 0605 - Z01A 1000 1561190005 The part number of a lead-free product has the trailing characters "E1". DS04-27262-3E 45 MB39A136 MB39A136PFT RECOMMENDED CONDITIONS OF MOISTURE SENSITIVITY LEVEL [FUJITSU SEMICONDUCTOR Recommended Mounting Conditions] Item Condition Mounting Method IR (infrared reflow) , Manual soldering (partial heating method) Mounting times 2 times Storage period Storage conditions Before opening Please use it within two years after Manufacture. From opening to the 2nd reflow Less than 8 days When the storage period after opening was exceeded Please process within 8 days after baking (125 C, 24h) 5 C to 30 C, 70%RH or less (the lowest possible humidity) [Mounting Conditions] (1) IR (infrared reflow) 260C 255C Main heating 170 C to 190 C (b) RT (a) "H" level : 260 C Max (a) Temperature increase gradient (b) Preliminary heating (c) Temperature increase gradient (d) Peak temperature (d') Main heating (e) Cooling (c) (d) (e) (d') : Average 1 C/s to 4 C/s : Temperature 170 C to 190 C, 60 s to 180 s : Average 1 C/s to 4 C/s : Temperature 260 C Max; 255 C or more, 10 s or less : Temperature 230 C or more, 40 s or less or Temperature 225 C or more, 60 s or less or Temperature 220 C or more, 80 s or less : Natural cooling or forced cooling Note: Temperature : on the top of the package body (2) Manual soldering (partial heating method) Temperature at the tip of an soldering iron: 400 C max Time: Five seconds or below per pin 46 DS04-27262-3E MB39A136 PACKAGE DIMENSIONS 24-pin plastic TSSOP Lead pitch 0.50 mm Package width x package length 4.40 mm x 6.50 mm Lead shape Gullwing Sealing method Plastic mold Mounting height 1.20 mm MAX Weight 0.08 g (FPT-24P-M09) 24-pin plastic TSSOP (FPT-24P-M09) Note 1) Pins width and pins thickness include plating thickness. Note 2) Pins width do not include tie bar cutting remainder. Note 3) #: These dimensions do not include resin protrusion. # 6.500.10(.256.004) 0.1450.045 (.0057.0018) 24 13 BTM E-MARK # 4.400.10 6.400.20 (.173.004) (.252.008) INDEX Details of "A" part +0.10 1.10 -0.15 +.004 (Mounting height) .043 -.006 1 12 0.50(.020) "A" +0.07 0.20 -0.02 .008 +.003 -.001 0.13(.005) M 0~8 0.600.15 (.024.006) 0.100.05 (Stand off) (.004.002) 0.10(.004) C 2007-2010 FUJITSU SEMICONDUCTOR LIMITED F24032S-c-2-5 Dimensions in mm (inches). Note: The values in parentheses are reference values. Please check the latest package dimension at the following URL. http://edevice.fujitsu.com/package/en-search/ DS04-27262-3E 47 MB39A136 CONTENTS - 48 page DESCRIPTION .................................................................................................................................................... 1 FEATURES .......................................................................................................................................................... 1 APPLICATION ..................................................................................................................................................... 1 PIN ASSIGNMENT ............................................................................................................................................. 2 PIN DESCRIPTION ............................................................................................................................................ 3 BLOCK DIAGRAM .............................................................................................................................................. 4 ABSOLUTE MAXIMUM RATINGS ................................................................................................................... 5 RECOMMENDED OPERATING CONDITIONS ............................................................................................ 6 ELECTRICAL CHARACTERISTICS ................................................................................................................ 7 TYPICAL CHARACTERISTICS ........................................................................................................................ 11 FUNCTION DESCRIPTION .............................................................................................................................. 13 PROTECTION FUNCTION TABLE .................................................................................................................. 17 I/O PIN EQUIVALENT CIRCUIT DIAGRAM ................................................................................................... 18 EXAMPLE APPLICATION CIRCUIT ................................................................................................................ 20 PARTS LIST ......................................................................................................................................................... 21 APPLICATION NOTE ......................................................................................................................................... 23 REFERENCE DATA ........................................................................................................................................... 40 USAGE PRECAUTION ...................................................................................................................................... 42 ORDERING INFORMATION ............................................................................................................................. 43 EV BOARD ORDERING INFORMATION ....................................................................................................... 43 RoHS COMPLIANCE INFORMATION OF LEAD (Pb) FREE VERSION ................................................... 44 MARKING FORMAT (Lead Free version) ....................................................................................................... 44 LABELING SAMPLE (Lead free version) ........................................................................................................ 45 MB39A136PFT RECOMMENDED CONDITIONS OF MOISTURE SENSITIVITY LEVEL ..................... 46 PACKAGE DIMENSIONS .................................................................................................................................. 47 DS04-27262-3E MB39A136 MEMO DS04-27262-3E 49 MB39A136 MEMO 50 DS04-27262-3E MB39A136 MEMO DS04-27262-3E 51 MB39A136 FUJITSU SEMICONDUCTOR LIMITED Nomura Fudosan Shin-yokohama Bldg. 10-23, Shin-yokohama 2-Chome, Kohoku-ku Yokohama Kanagawa 222-0033, Japan Tel: +81-45-415-5858 http://jp.fujitsu.com/fsl/en/ For further information please contact: North and South America FUJITSU SEMICONDUCTOR AMERICA, INC. 1250 E. Arques Avenue, M/S 333 Sunnyvale, CA 94085-5401, U.S.A. Tel: +1-408-737-5600 Fax: +1-408-737-5999 http://us.fujitsu.com/micro/ Asia Pacific FUJITSU SEMICONDUCTOR ASIA PTE. LTD. 151 Lorong Chuan, #05-08 New Tech Park 556741 Singapore Tel : +65-6281-0770 Fax : +65-6281-0220 http://www.fujitsu.com/sg/services/micro/semiconductor/ Europe FUJITSU SEMICONDUCTOR EUROPE GmbH Pittlerstrasse 47, 63225 Langen, Germany Tel: +49-6103-690-0 Fax: +49-6103-690-122 http://emea.fujitsu.com/semiconductor/ FUJITSU SEMICONDUCTOR SHANGHAI CO., LTD. Rm. 3102, Bund Center, No.222 Yan An Road (E), Shanghai 200002, China Tel : +86-21-6146-3688 Fax : +86-21-6335-1605 http://cn.fujitsu.com/fss/ Korea FUJITSU SEMICONDUCTOR KOREA LTD. 206 Kosmo Tower Building, 1002 Daechi-Dong, Gangnam-Gu, Seoul 135-280, Republic of Korea Tel: +82-2-3484-7100 Fax: +82-2-3484-7111 http://kr.fujitsu.com/fmk/ FUJITSU SEMICONDUCTOR PACIFIC ASIA LTD. 10/F., World Commerce Centre, 11 Canton Road, Tsimshatsui, Kowloon, Hong Kong Tel : +852-2377-0226 Fax : +852-2376-3269 http://cn.fujitsu.com/fsp/ Specifications are subject to change without notice. For further information please contact each office. All Rights Reserved. The contents of this document are subject to change without notice. Customers are advised to consult with sales representatives before ordering. The information, such as descriptions of function and application circuit examples, in this document are presented solely for the purpose of reference to show examples of operations and uses of FUJITSU SEMICONDUCTOR device; FUJITSU SEMICONDUCTOR does not warrant proper operation of the device with respect to use based on such information. When you develop equipment incorporating the device based on such information, you must assume any responsibility arising out of such use of the information. FUJITSU SEMICONDUCTOR assumes no liability for any damages whatsoever arising out of the use of the information. Any information in this document, including descriptions of function and schematic diagrams, shall not be construed as license of the use or exercise of any intellectual property right, such as patent right or copyright, or any other right of FUJITSU SEMICONDUCTOR or any third party or does FUJITSU SEMICONDUCTOR warrant non-infringement of any third-party's intellectual property right or other right by using such information. FUJITSU SEMICONDUCTOR assumes no liability for any infringement of the intellectual property rights or other rights of third parties which would result from the use of information contained herein. The products described in this document are designed, developed and manufactured as contemplated for general use, including without limitation, ordinary industrial use, general office use, personal use, and household use, but are not designed, developed and manufactured as contemplated (1) for use accompanying fatal risks or dangers that, unless extremely high safety is secured, could have a serious effect to the public, and could lead directly to death, personal injury, severe physical damage or other loss (i.e., nuclear reaction control in nuclear facility, aircraft flight control, air traffic control, mass transport control, medical life support system, missile launch control in weapon system), or (2) for use requiring extremely high reliability (i.e., submersible repeater and artificial satellite). Please note that FUJITSU SEMICONDUCTOR will not be liable against you and/or any third party for any claims or damages arising in connection with above-mentioned uses of the products. Any semiconductor devices have an inherent chance of failure. You must protect against injury, damage or loss from such failures by incorporating safety design measures into your facility and equipment such as redundancy, fire protection, and prevention of overcurrent levels and other abnormal operating conditions. Exportation/release of any products described in this document may require necessary procedures in accordance with the regulations of the Foreign Exchange and Foreign Trade Control Law of Japan and/or US export control laws. The company names and brand names herein are the trademarks or registered trademarks of their respective owners. Edited: Sales Promotion Department