FUJITSU SEMICONDUCTOR DATA SHEET DS04-27221-4E ASSP For Power Supply Applications With Power Mode Switching Function 2-ch DC/DC Converter IC With Synchronous Rectifier MB3821 DESCRIPTION The MB3821 is a pulse width modulation (PWM) type 2-channel DC/DC converter IC with synchronous rectification designed for low voltage, high efficiency operation in high precision and high frequency applications, ideal for down conversion. A normal/low-power mode selection is provided, ideal for an internal power supply (3.3V, 5V) in applications with substantial load current variation, such as notebook computers. This product is covered by US Patent Number 6,147,477. FEATURES * Synchronous rectification * High efficiency : 93 % (normal power mode, VIN = 6 V, load 1 A) : 84 % (low power mode, VIN = 6 V, load 20 mA) * * * * * Built-in power mode selector circuit Reference voltage accuracy : 2.5V 2 % Built-in error amp input control type soft-start circuit Totem pole type output for N-ch MOSFET applications Built-in timer-latch type short protection circuit PACKAGE 24-pin, Plastic SSOP (FPT-24P-M03) MB3821 PIN ASSIGNMENT (TOP VIEW) CT : 1 24 : VREF RT : 2 23: VCC GND : 3 IN (CH1) 22 : CSCP CS1 : 4 21 : CS2 -IN1 : 5 20 : -IN2 FB1 : 6 19 : FB2 SEL : 7 18 : CTL OUT1-1 : 8 OUT (CH2) 17 : OUT1-2 VS1 : 9 16 : VS2 CB1 : 10 15 : CB2 OUT2-1 : 11 14: OUT2-2 GND(0) : 12 13 :VB (FPT-24P-M03) 2 IN OUT MB3821 PIN DESCRIPTION Pin No. Symbol I/O Descriptions 1 CT -- Triangular wave oscillator frequency setting capacitance connection pin. 2 RT -- Triangular wave oscillator frequency setting resistance connection pin. 3 GND -- Ground pin. 4 CS1 -- Capacitor connection pin for Channel 1 soft-start (also channel control). 5 -IN1 I Channel 1 error amplifier inverted input pin. 6 FB1 O Channel 1 error amplifier output pin 7 SEL I Mode select pin. Set the SEL pin to "H" level to switch the IC to low power mode. 8 OUT1-1 I Totem pole type output pin (external main side FET gate drive). 9 VS1 -- Channel 1 external main side FET source connection pin. 10 CB1 -- Channel 1 boot capacitance connection pin. 11 OUT2-1 O Channel 1 totem pole output pin (external main side FET gate drive). 12 GND(0) -- Ground pin for output circuit. 13 VB -- Power supply pin for output circuit. 14 OUT2-2 O Channel 2 totem pole output pin (external synchronous rectifier side FET gate drive). 15 CB2 -- Channel 2 boot capacitance connection pin. 16 VS2 -- Channel 2 external main side FET source connection pin. 17 OUT1-2 O Channel 2 totem pole output pin (external main side FET gate drive). 18 CTL I Power supply control pin. Set CTL pin to "L" to switch the IC to standby mode. 19 FB2 O Channel 2 error amplifier output pin. 20 -IN2 I Channel 2 error amplifier inverted input pin. 21 CS2 -- Channel 2 soft-start capacitance connection pin(also channel control). 22 CSCP -- Timer-latch short circuit protection capacitance connection pin. 23 VCC -- Reference power supply, control circuit power supply pin. 24 VREF O Reference voltage output pin. 3 MB3821 BLOCK DIAGRAM 1 1 13 VB 10 CB1 FB1 6 Error Amp. PWM Comp.1 - + + -IN1 5 CS1 4 23 VCC + 8 OUT1-1 Drive - 1.26 V 9 VS1 PWM Comp.2 (40 mV) + - 11 OUT2-1 Drive < CH1 > 15 CB2 FB2 19 Error Amp. PWM Comp.1 - + + -IN2 20 CS2 21 + 17 OUT1-2 Drive - 1.26 V 16 VS2 PWM Comp.2 (40 mV) + - 14 OUT2-2 Drive < CH2 > SCP Comp. 1 12 GND (0) - - + 1.9 V 2.1 V 1.3 V bias bias CSCP 22 S R Latch UVLO 7 SEL 4 Ref Power (2.5 V) ON/OFF OSC 1 CT 2 RT 24 VREF 3 GND 18 CTL MB3821 ABSOLUTE MAXIMUM RAGINGS Parameter Symbol Conditions Power supply voltage VCC Bias voltage Rating Unit Min Max -- -- 32 V VB -- -- 17 V Output current Io -- -- 50 mA Output peak current Io Duty 5 % -- 500 mA Power dissipation PD Ta +25C -- 740* mW Storage temperature Tstg -55 +125 C -- *: The packages are mounted on the epoxy board (10 cm x 10 cm). 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. RECOMMENDED OPERATING CONDITIONS Parameter Symbol Conditions Power supply voltage VCC Bias voltage Value Unit Min Typ Max -- 4.5 16 30 V VB -- -- 6 16 V Reference voltage output current IOR -- -1 -- 0 mA Input voltage VIN -IN pin 0 -- VCC - 1.8 V SEL, CTL pin 0 -- 30 V Output current IO OUT pin -30 -- 30 mA Output peak current Io Duty 5 % -300 -- 300 mA Timing capacitance CT -- 150 500 15000 pF Timing resistance RT -- 6.8 10 12 k Oscillator frequency fOSC SEL = 0 V (Normal mode) 10 200 500 kHz SEL = 5 V (Low power mode) 1 20 50 kHz Soft-start capacitance CS -- -- 0.1 1.0 F CSCP -- -- 0.01 1.0 F Boot capacitance CB -- -- 0.1 1.0 F Operating ambient temperature Ta -- -30 +25 +85 C Short detection capacitance 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 FUJITSU representatives beforehand. 5 MB3821 ELECTRICAL CHARACTERISTICS Short circuit detection block Soft-start block Under voltage lockout protection circuit block(U.V.L.O) Reference voltage block (VCC = 16 V, SEL =0 V, Ta = +25C) Parameter Symbol Pin No. Output voltage VREF 24 VREF =0 mA VREF/ VREF 24 Input stability Line Load stability Value Unit Min Typ Max 2.45 2.50 2.55 V Ta = -30C to +85C -- 0.5* -- % 24 VCC = 4.5 V to 30 V -- -- 15 mV Load 24 VREF = 0 mA to -1.0 mA -- -- 15 mV Short-circuit output current IOS 24 VREF = 1 V -60 -25 -- mA Threshold voltage VTH 4,21 VCC = 3.2 3.5 3.8 V Hysteresis width VH 4,21 -- -- 0.18 -- V Reset voltage VRST 4,21 -- 2.4 2.8 -- V Charge current ICS 4,21 -- -1.4 -1.0 -0.6 A Input standby voltage VSTB 4,21 -- -- 50 100 mV Threshold voltage VTH 4,21 -- 0.63 0.68 0.73 V Input source current ICSCP 22 -- -1.4 -1.0 -0.6 A Short detection time tSCP 22 4.5 6.8 12.2 ms Input standby voltage VSTB 22 -- -- 50 100 mV VI 22 -- -- 50 100 mV SEL = 0 V 180 200 220 kHz SEL = 5 V 16 20 24 kHz Output voltage temperature variation Input latch voltage Oscillator frequency Triangular wave oscillator block Conditions Mode select voltage Input current fOSC CSCP = 0.01 F 8,11, CT = 500pF, 14,17 RT = 10 k VLOW 7 Low power mode 2.0 -- -- V VHI 7 Normal mode -- -- 1.0 V ISEL 7 SEL = 5 V -- 50 80 A SEL = 0 V -- 1 10 % Frequency stability for voltage f/fdv CT = 500pF, 8,11, RT = 10 k, 14,17 VCC = 4.5V to 30V SEL = 5 V -- 1 10 % Frequency stability for temperature f/fdt SEL = 0 V CT = 500pF, 8,11, RT = 10 k, 14,17 Ta = -30C to +85C SEL = 5 V -- 1* -- % -- 1* -- % *: Standard design value. (Continued) 6 MB3821 (Continued) (VCC = 16 V, SEL =0 V, Ta = +25C) Error amplifier block Parameter PWM Comp. block Dead time control block Output block (Drive) Conditions VTH 6,19 FB = 1.6 V VT temperature stability VT /VT 6,19 Ta = -30C to +85C Value Unit Min Typ Max 1.235 1.260 1.285 V -- 0.5* -- % -200 -50 -- nA Input bias current IB 5,20 -IN = 0 V Voltage gain AV 6,19 DC 60 100 -- dB Frequency bandwidth BW 6,19 AV = 0 dB -- 800* -- kHz VOH 6,19 -- VREF - 0.3 -- -- V VOL 6,19 -- -- 0.8 1.0 V Output voltage Output sink current ISOURCE 6,19 FB = 1.6 V -- -90 -45 A ISINK 6,19 FB = 1.6 V 1.5 6.0 -- mA Duty cycle = 0 % 1.2 1.3 -- V Duty cycle = Dtr -- 1.9 2.0 V SEL = 0 V 85 90 95 % SEL = 5 V 89 94 99 % IO = -30 mA CB - 1.4 CB - 1.1 -- V IO = 30 mA -- VS + 1.1 VS + 1.4 V VTL Threshold voltage VTH Maximum duty cycle Output voltage (Main side) Output voltage (Synchronous rectifier side) Diode voltage Control block Pin No. Threshold voltage Output source current General Symbol Dtr 8,11 14,17 8,11, CT = 500 pF 14,17 RT = 10 k VOH 8,17 VOL 8,17 VOH 11,14 IO = -30 mA VB - 1.4 VB - 1.1 -- V VOL 11,14 IO = 30 mA -- 0.1 0.5 V VS = 16 V CB = 22 V VDIODE 13 IO = 10 mA -- 1.0 1.1 V VIH 18 IC active mode 2.0 -- -- V VIL 18 IC standby mode -- -- 1.0 V Input current ICTL 18 CTL = 5 V -- 50 80 A Standby current ICCS 23 CTL = 0 V -- -- 10 A 23 SEL = 0 V (Normal mode) -- 5.2 7.8 mA 23 SEL = 5 V (Low power mode) -- 1.0 1.5 mA CTL input voltage Power supply current ICC *: Standard design value. 7 MB3821 TYPICAL CHARACTERISTICS 10 Ta = +25 C SEL = 0 V 8 6 4 2 0 10 20 35 40 2.0 1.6 1.4 1.2 1.0 0.8 0.6 0.4 0.2 0.0 0 50 10 20 35 40 50 Power supply voltage VCC (V) Power supply voltage VCC (V) Reference voltage vs. power supply voltage Reference voltage vs. power supply voltage 5 5 Ta = +25 C IOR = 0 mA 4 3 2 1 Ta = +25 C IOR = 0 mA 4 3 2 1 0 0 0 10 20 30 40 50 0 Power supply voltage VCC (V) 2 3 5 1.0 Reference voltage VREF (V) VCC = 16 V CTL = 5 V IOR = 0 mA 1.5 0.5 0.0 -0.5 -1.0 -1.5 -20 0 20 40 60 80 Ambient temperature Ta (C) 4 5 Reference voltage vs. control voltage 2.0 -2.0 -40 1 Power supply voltage VCC (V) Reference voltage vs. ambient temperature Reference voltage VREF (%) Ta = +25 C SEL = 5 V 1.8 Reference voltage VREF (V) Reference voltage VREF (V) 0 Power supply current vs. power supply voltage Power supply current ICC (mA) Power supply current ICC (mA) Power supply current vs. power supply voltage 100 Ta = +25 C VCC = 16 V SEL = 0 V IOR = 0 mA 4 3 2 1 0 0 10 20 30 40 50 Control voltage VCTL (V) (Continued) 8 MB3821 (Continued) Select pin current vs. select pin voltage Control current vs. control voltage 500 Ta = +25 C VCC = 16 V SEL = 0 V 400 Select pin current ISEL (A) Control current ICTL (A) 500 300 200 100 0 0 10 20 30 40 1.5 Lower 1M Triangular wave upper and lower limit voltage VCT (V) Triangular wave upper and lower limit voltage VCT (V) Upper 100 k 100 100 k 10 k 1k 10 p 100 p 1n 10 n CT capacitance (F) 30 40 50 100 n VCC = 16 V CTL = 5 V SEL = 0 V 2.4 2.2 2.0 Upper 1.8 RT = 10 k, CT = 500 pF 1.6 1.4 1.2 Lower 1.0 0.8 0.6 -40 -20 0 20 40 60 80 100 Ambient temperature Ta (C) Triangular wave oscillator frequency fOSC (Hz) Triangular wave oscillator frequency fOSC (Hz) VCC = 16 V CTL = 5 V SEL = 0 V RT = 10 k 1M 20 2.6 Triangular wave oscillator frequency fOSC (Hz) Triangular wave oscillator frequency vs. CT capacitance 10 M 10 Select pin voltage VSEL (V) Triangular wave upper and lower limit voltage vs. ambient temperature 2.0 10 k 200 0 Ta = +25 C VCC = 16.0 V CTL = 5 V 0.5 1k 300 0 Triangular wave upper and lower limit voltage vs. triangular wave oscillator frequency 1.0 400 50 Control voltage VCTL (V) 2.5 Ta = +25 C VCC = 16 V CTL = 5 V Triangular wave oscillator frequency vs. CT capacitance 1M VCC = 16 V CTL = 5 V SEL = 5 V RT = 10 k 100 k 10 k 1k 100 10 p 100 p 1n 10 n 100 n CT capacitance (F) (Continued) 9 MB3821 (Continued) Duty vs. oscillator frequency (ch1) Duty vs. oscillator frequency (ch1) 100 100 Ta = +25 C VCC = 16 V CTL = 5 V SEL = 0 V 90 70 60 60 Duty Dtr (%) 70 50 40 30 40 30 20 10 10 100 k Oscillator frequency fOSC (Hz) Triangular wave oscillator frequency vs. timing resistance 10 M Ta = +25 C VCC = 16 V CTL = 5 V SEL = 0 V 1M CT = 100 pF 100 k CT = 500 pF 10 k CT = 15000 pF 1k 1k 10 k 100 k Timing resistance RT () Triangular wave oscillator frequency vs. power supply voltage 250 Ta = +25 C CTL = 5 V SEL = 0 V 240 230 220 210 RT = 10 k, CT = 500 pF 200 190 180 170 160 150 0 10 20 0 100 1M 30 40 Power supply voltage VCC (V) 50 Triangular wave oscillator frequency fOSC (Hz) Triangular wave oscillator frequency fOSC (Hz) Triangular wave oscillator frequency fOSC (kHz) 50 20 0 10 k 10 80 1k 10 k Oscillator frequency fOSC (Hz) Triangular wave oscillator frequency vs. timing resistance 1M Ta = +25 C VCC = 16 V CTL = 5 V SEL = 5 V 100 k CT = 100 pF 10 k CT = 500 pF 1k CT = 15000 pF 100 1k Triangular wave oscillator frequency fOSC (kHz) Duty Dtr (%) 80 Ta = +25 C VCC = 16 V CTL = 5 V SEL = 5 V 90 10 k 100 k Timing resistance RT () Triangular wave oscillator frequency vs. power supply voltage 25 Ta = +25 C CTL = 5 V SEL = 5 V 24 23 22 RT = 10 k, CT = 500 pF 21 20 19 18 17 16 15 0 10 20 30 40 Power supply voltage VCC (V) 50 MB3821 Triangular wave oscillator frequency vs. ambient temperature 250 VCC = 16 V CTL = 5 V SEL = 0 V 240 230 220 210 RT = 10 k, CT = 500 pF 200 190 180 170 160 150 -40 -20 0 20 40 60 80 100 Ambient temperature Ta (C) Triangular wave oscillator frequency fOSC (kHz) Triangular wave oscillator frequency fOSC (kHz) (Continued) Triangular wave oscillator frequency vs. ambient temperature 25 VCC = 16 V CTL = 5 V SEL = 5 V 24 23 22 21 RT = 10 k, CT = 500 pF 20 19 18 17 16 15 -40 -20 0 20 40 60 80 100 Ambient temperature Ta (C) Error amplifier,gain and phase vs. frequency (ch1) Ta = +25 C AV 90 10 45 0 0 -10 -45 -20 -90 -30 -135 -40 -180 100 1k 10 k 100 k 1M 2.52 V 11 k 1 F 2.4 k 240 k - + 11 k Error amplifier 1.26 V 10 M Frequency f (Hz) Power dissipation vs. ambient temperature Power dissipation PD (mW) Gain AV (dB) 20 180 135 30 Phase (deg) 40 800 740 700 600 500 400 300 200 100 0 -40 -20 0 20 40 60 80 100 Ambient temperature Ta (C) 11 MB3821 FUNCTIONAL DESCRIPTION 1. DC/DC Converter Function (1) Reference voltage circuit (Ref) The reference voltage circuit generates a temperature-compensated reference voltage ( 2.50 V) using the voltage supplied from the power supply terminal (pin 23). This voltage is used as the reference voltage for the internal circuits of the IC. The reference voltage can also be supplied to an external device from the VREF terminal (pin 24) up to a maximum current of 1mA. (2) Triangular-wave oscillator circuit (OSC) By connecting a frequency setting capacitor and a resistor to the CT (pin 1) and the RT (pin 2) terminals, it is possible to generate any desired triangular oscillation waveform. The triangular wave is input to the PWM comparator within the IC. (3) Error amplifier This amplifier detects the output voltage of the DC/DC converter and outputs a PWM control signal accordingly. The system can be provided with stable phase compensation by connecting a feedback resistor and capacitor between the FB pin and the -IN pin of the error amplifier to create the desired level of loop gain. Also, by connecting soft-start capacitance to the CS terminal, which is the non inverted input pin for the error amplifier, it is possible to prevent current surges when the power supply is started. By using the error amplifier for soft-start detection, it is possible to operate with a fixed soft-start interval independent of the output load on the DC/ DC converter. (4) PWM comparators (PWM Comp.1, PWM Comp.2) PWM Comp.1 and PWM Comp.2 are voltage-pulse width modulators that control the output duty according to input voltage. PWM Comp.1 controls the pulse width on the main side output circuit, and PWM Comp.2 controls the pulse width on the synchronous rectifier side output circuit. The triangular wave generated by the triangular wave oscillator is compared to the error amplifier output voltage, and in the intervals when the error amplifier voltage is higher than the triangular wave, the main side output transistor is switched on and the synchronous rectifier side output transistor is switched off. Also, PWM Comp.1 is set to a maximum duty cycle of approximately 90 % (normal mode). (5) Output circuit (Drive) The output circuits is comprised of a totem-pole configuration on both the main side and synchronous rectifier side, and can drive an external N-ch MOSFET. (6) Mode select circuit (SEL) The SEL terminal (pin 7) can set either channel to normal mode or low power mode. In low power mode the triangular oscillator frequency is set to approximately 1/10 of normal mode, reducing the internal power consumption of the chip and enabling high efficiency power supply at light load levels. (7) Power supply control circuit (CTL) The CTL terminal (pin 18) is used for power supply on/off control (standby power consumption is 10 A or less). 2. Protection Functions (1) Under Voltage Lockout Circuit (UVLO) Power-on surge states or sudden drops in supply voltage can cause a control IC to operate abnormally, leading to destruction or damage to system elements. The under voltage lockout circuit detects the internal reference voltage level from the supply voltage, and shuts off the output transistors so that the inactive interval becomes 100%, holding the CSCP terminal (pin 22) voltage at "L" level. Operation is restored as soon as the supply voltage exceeds the under voltage lockout circuit threshold voltage. 12 MB3821 (2) Timer-Latch Short Circuit Protection Circuit (SCP) This circuit detects the output voltage level from the error amplifier. When the error amplifier output voltage exceeds approximately 2.1V, a timer circuit is activated and charges the external capacitor at the CSCP terminal (pin 22). If the error amplifier output does not return to normal range before the capacitor voltage reaches approximately 0.7V, a latch circuit is activated and sets both the main and synchronous rectifier side output pins to "L" level. After the short protection circuit has been activated, it is reset by simply restarting the power supply. (See "METHOD OF SETTING TIME CONSTANT FOR TIMER LATCH SHORT-CIRCUIT PROTECTION CIRCUIT".) 13 MB3821 METHOD OF SETTING SOFT-START TIME To provide a soft-start by preventing current surges at power-on, soft-start capacitors (Cs1, Cs2) are connected to both channels, the CS1 pin (pin 4) for CH1 and the CS2 pin (pin 21) for CH2. When the IC is started (when the CTL pin (pin 18) goes to "H" level, and Vcc UVLO threshold voltage), transistors Q2 and Q3 switch off and the CS1 and CS2 pins begin charging the external soft-start capacitors (Cs1, Cs2) at 1 A. The error amplifier contributes to a soft-start with the proportionate output voltage to the CS1 and CS2 pin voltage regardless of the load current on the DC/DC converter. The soft-start time can be calculated by the following formula. Soft-start time (time to 100% output) tS(s) =: 1.26 x CS (F) Soft-start circuit 1 A 1 A FB1 6 -IN1 5 - + + Error Amp.1 Output stage 8 OUT1-1 4 CS1 1.26 V Output stage Cs1 Q2 11 OUT2-1 FB2 19 -IN2 20 - + + Error Amp.2 Output stage OUT1-2 21 CS2 1.26 V Cs2 Output stage Q3 SCP Comp. bias 22 S CSCP Q1 14 Q4 R Latch 14 OUT2-2 - - + 1 A CSCP 17 2.1 V bias UVLO Ref (2.5V) Power ON/OFF 18 CTL MB3821 TREATMENT WITHOUT USING CS TERMINAL When you do not use the soft-start circuit, open the CS1 terminal (pin 4) and CS2 terminal (pin 21). Treatment When Not Using SCP 4 CS1 CS2 21 15 MB3821 METHOD OF SETTING TIME CONSTANT FOR TIMER-LATCH SHORT-CIRCUIT PROTECTION CIRCUIT The short detection comparator (SCP comparator) constantly compares the error amplifier output level to the reference voltage. While the switching regulator load conditions are stable on all channels, the short detection comparator output remains at "H" level, transistor Q1 is on, and the CSCP terminal (pin 22) is held at input standby voltage (VSTB=: 50mV). If the load conditions change rapidly due to a short-circuiting of load, causing the output voltage to drop, the output from the short detection comparator goes to "L" level. This causes transistor Q1 to turn off and the external short protection capacitor CSCP connected to the CSCP pin to charge at 1.0 A. Short Detection Time tSCP(s) =: 0.7 x CSCP (F) When the capacitor CSCP is charged to the threshold voltage VTH =: 0.7 V, the SR latch is set, and the external FET is turned off (inactive interval is set to 100%). At this point, the SR latch input is closed and the CSCP terminal is held at input latch voltage (VI =: 50 mV). Timer-latch short-circuit protection circuit 1 A 1 A FB1 6 -IN1 5 - + + Error Amp.1 Output stage 8 OUT1-1 4 CS1 1.26 V Output stage Cs1 Q2 11 OUT2-1 FB2 19 -IN2 20 - + + Error Amp.2 Output stage CS2 1.26 V Cs2 Output stage Q3 SCP Comp. bias 22 S CSCP Q1 16 Q4 R Latch 14 OUT2-2 - - + 1 A CSCP 17 OUT1-2 21 2.1 V bias UVLO Ref (2.5V) Power ON/OFF 18 CTL MB3821 TREATMENT WITHOUT USING CSCP TERMINAL When you do not use the timer latch short-circuit protection circuit, connect the CSCP terminal (pin 22) to GND with the shortest distance. Treatment When Not Using SCP 3 GND CSCP 22 Channel Control Method On/off controls for either channel are enabled by setting the CS pins. Setting Conditions CS pin setting Channel output state CS1 CS2 CH1 CH2 GND GND OFF OFF GND Open OFF ON Open GND ON OFF Open Open ON ON 17 MB3821 METHOD OF SETTING OSCILLATOR FREQUENCY Oscillator Frequency can be set by timing capacitor (CT) connected to CT pin (pin 1) and timing resistor (RT) connected to RT pin (pin 2). Oscillator frequency * Normal mode fOSC (kHz) =: 1000000 CT(pF) x RT(k) * Low power mode fOSC (kHz) =: 18 100000 CT(pF) x RT(k) 0.1 F 4 5 21 20 19 22 24 3 VREF GND OFF : CTL= 0 V 10 k RT ON : CTL= 5 V 2 Ref Power (2.5 V) ON/OFF Low power mode : SEL= 5 V 500 pF 7 1 SEL CT OSC bias 1.3 V 1.9 V Normal mode : SEL= 0 V UVLO Drive Drive Drive Drive Output ON/OFF signal S R Latch bias 2.1 V - PWM Comp.2 (40 mV) + - PWM Comp.1 + - + PWM Comp.2 (40 mV) - PWM Comp.1 + OUT2-1 VS1 OUT1-1 VCC CB1 + 100 F - Si9410 0.1 F 100 F Si9410 + - RB415D OUT 6.8 F 47 H + - IO 1 6.8 F + - IO 2 13 k 21 k <3.3 V> VO2 3.3 k 9.8 k S-81250 : Seiko Instruments Inc. 2SK1299 : SANYO Electric Co., Ltd. RB415D : ROHM Co., LTD DE5SC3ML : SHINDENGEN ELECTRIC MANUFACTURING Co., Ltd. DE5SC3ML 150 F B Si9410 47 H VO1 <5.0 V> DE5SC3ML 150 F A Si9410 100 F + - 0.1 F S-81250 Reg. 4.7 F IN Si9410 : Siliconix Co. GND (0) OUT2-2 VS2 OUT1-2 CB2 18 CTL 12 14 16 17 15 RB415D 11 9 8 23 10 13 VB 10 H Mode select signal - - + 1.26 V Error Amp. - + + << CH1>> 1.26 V Error Amp. - + + 1 A << CH2>> SCP Comp. 1 A 1 A 6 0.1 F CS2 -IN2 FB2 CSCP 2SK1299 10 k 100 k 10 k VXCS2 B 10 k 0.022 F CS1 -IN1 FB1 0.1 F 2SK1299 10 k 100 k ON/OFF Vin 10 k VXCS1 ON/OFF 0.022 F 10 k A Iin MB3821 APPLICATION EXAMPLE 19 MB3821 REFERENCE DATA * Load characteristic Conversion efficiency vs. load current Conversion efficiency vs. load current 5V output (3.3V output OFF) 3.3 V output (5 V output OFF) 100 Vin 16 k V RT = 10 CT = 500 pF VXCS1 = 5 V VXCS2 = 0 V 95 90 RT = 10 k CT = 500 pF VXCS1 = 5 V VXCS2 = 0 V 95 Vin = 6 V 85 Vin = 16 V 80 75 70 Normal mode (SEL= 0V) 65 60 55 50 Low power mode (SEL= 5V) 45 Conversion efficiency (%) Conversion efficiency (%) 100 40 90 85 Vin = 6 V Vin = 16 V 80 75 Normal mode (SEL= 0V) 70 65 60 55 Low power mode (SEL= 5V) 50 45 40 0.001 0.005 0.01 0.05 0.1 0.5 1 5 10 0.001 0.005 0.01 0.05 0.1 0.5 1 5 10 Load current IO (A) Load current IO (A) * Normal mode Conversion efficiency vs. Input voltage Conversion efficiency vs. Input voltage 100 5 V output (3.3 V output OFF) 3.3 V output (5 V output OFF) Conversion efficiency (%) Conversion efficiency (%) 100 95 90 85 RT = 10 k CT = 500 pF IO = 1 A VXCS1 = 5 V VXCS2 = 0 V SEL = 0 V 80 75 70 5 6 7 8 9 10 11 12 13 Input voltage Vin (V) 14 15 16 95 90 85 RT = 10 k CT = 500 pF IO = 1 A VXCS1 = 0 V VXCS2 = 5 V SEL = 0 V 80 75 70 5 6 7 8 9 10 11 12 13 14 15 16 Input voltage Vin (V) (Continued) 20 MB3821 (Continued)) * Low power mode Conversion efficiency vs. Input voltage Conversion efficiency vs. Input voltage 3.3 V output (5 V output OFF) 95 RT = 10 k CT = 500 pF IO = 20 mA VXCS1 = 5 V VXCS2 = 0 V SEL = 5 V 90 85 80 75 70 65 60 55 50 5 6 7 8 9 10 11 12 13 Input voltage Vin (V) 14 15 16 100 Conversion efficiency (%) Conversion efficiency (%) 100 5 V output (3.3 V output OFF) 95 RT = 10 k CT = 500 pF IO = 20 mA VXCS1 = 0 V VXCS2 = 5 V SEL = 5 V 90 85 80 75 70 65 60 55 50 5 6 7 8 9 10 11 12 13 14 15 16 Input voltage Vin (V) 21 MB3821 NOTES ON USE * Take account of common impedance when designing the earth line on a printed wiring board. * Take measures against static electricity. - For semiconductors, use antistatic or conductive containers. - When storing or carrying a printed circuit board after chip mounting, put it in a conductive bag or container. - The work table, tools and measuring instruments must be grounded. - The worker must put on a grounding device containing 250 k to 1 M resistors in series. * Do not apply a negative voltage. - Applying a negative voltage of -0.3 V or less to an LSI may generate a parasitic transistor, resulting in malfunction. ORDERING INFORMATION Part number MB3821PFV 22 Package 24-pin Plastic SSOP (FPT-24P-M03) Remarks MB3821 PACKAGE DIMENSION Note 1) *1 : Resin protrusion. (Each side : +0.15 (.006) Max) . Note 2) *2 : These dimensions do not include resin protrusion. Note 3) Pins width and pins thickness include plating thickness. Note 4) Pins width do not include tie bar cutting remainder. 24-pin Plastic SSOP (FPT-24P-M03) 0.170.03 (.007.001) *17.750.10(.305.004) 24 13 *2 5.600.10 7.600.20 (.220.004) (.299.008) INDEX Details of "A" part +0.20 1.25 -0.10 +.008 .049 -.004 (Mounting height) 0.25(.010) 1 "A" 12 0.65(.026) 0.24 .009 +0.08 -0.07 +.003 -.003 0.13(.005) 0~8 M 0.500.20 (.020.008) 0.600.15 (.024.006) 0.100.10 (.004.004) (Stand off) 0.10(.004) C 2003 FUJITSU LIMITED F24018S-c-4-5 Dimensions in mm (inches) . Note : The values in parentheses are reference values. 23 MB3821 FUJITSU MEDIA DEVICES LIMITED All Rights Reserved. The contents of this document are subject to change without notice. Customers are advised to consult with FUJITSU MEDIA DEVICES 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 MEDIA DEVICES electronic device; FUJITSU MEDIA DEVICES 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 MEDIA DEVICES 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 MEDIA DEVICES or any third party or does FUJITSU MEDIA DEVICES warrant non-infringement of any third-party's intellectual property right or other right by using such information. FUJITSU MEDIA DEVICES 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, 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 MEDIA DEVICES 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 electronic devices have inherently a certain rate 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 over-current levels and other abnormal operating conditions. If any products described in this document represent goods or technologies subject to certain restrictions on export under the Foreign Exchange and Foreign Trade Control Law of Japan, the prior authorization by Japanese government should be required for export of those products from Japan. F0308 FUJITSU LIMITED Printed in Japan 24