SLUS577C - SEPTEMBER, 2003 - REVISED MARCH 2009 FEATURES D Controls Boost Preregulator to Near-Unity D D D D D D D D D D D D DESCRIPTION The UCC3817A and the UCC3818A family provides all the functions necessary for active power factor corrected preregulators. The controller achieves near unity power factor by shaping the ac input line current waveform to correspond to that of the ac input line voltage. Average current mode control maintains stable, low distortion sinusoidal line current. Power Factor Limits Line Distortion World Wide Line Operation Over-Voltage Protection Accurate Power Limiting Average Current Mode Control Improved Noise Immunity Improved Feed-Forward Line Regulation Leading Edge Modulation 150-A Typical Start-Up Current Low-Power BiCMOS Operation 12-V to 17-V Operation Frequency Range of 6 kHz to 220 kHz Designed in Texas Instrument's BiCMOS process, the UCC3817A/UCC3818A offers new features such as lower start-up current, lower power dissipation, overvoltage protection, a shunt UVLO detect circuitry, a leading-edge modulation technique to reduce ripple current in the bulk capacitor and an improved, low-offset (2 mV) current amplifier to reduce distortion at light load conditions. BLOCK DIAGRAM VCC 15 OVP/EN 10 16 V (FOR UCC3817A ONLY) SS 13 VAOUT 7 1.9 V VSENSE 11 - 0.33 V VOLTAGE ERROR AMP + VREF 16 DRVOUT 1 GND 2 PKLMT 10.5 V/10 V (UCC3818A) ZERO POWER VCC - + X / MULT X CURRENT AMP 8.0 V + OVP - - - + PWM S + X2 8 9 UVLO 16 V/10 V (UCC3817A) ENABLE + 7.5 V VFF - 7.5 V REFERENCE PWM LATCH OSC R CLK MIRROR 2:1 Q R CLK IAC OSCILLATOR 6 - + MOUT 5 4 3 12 14 CAI CAOUT RT CT UDG-03122 Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet. !" # $%&" !# '%() $!" *!"&+ *%$"# $ " #'&$ $!" # '& ",& "&# &-!# #"%&"# #"!*!* .!!"/+ *%$" '$&## 0 *&# " &$&##! )/ $)%*& "&#" 0 !)) '!!&"&#+ Copyright 2006 - 2009, Texas Instruments Incorporated www.ti.com 1 SLUS577C - SEPTEMBER, 2003 - REVISED MARCH 2009 DESCRIPTION (CONTINUED) The UCC3817A/18A family of PFC Controllers is directly pin for pin compatible with the UCC3817/18 family of devices. Only the output stage of UCC3817A family has been modified to allow use of a smaller external gate drive resistor values. For some power supply designs where an adequately high enough gate drive resistor can not be used, the UCC3817A/18A family offers a more robust output stage at the cost of increasing the internal gate resistances. The gate drive of the UC3817A/18A family however remains strong at 1.2 A of peak current capability. UCC3817A offers an on-chip shunt regulator with low start-up current, suitable for applications utilizing a bootstrap supply. UCC3818A is intended for applications with a fixed supply (VCC). Both devices are available in the 16-pin D, N and PW packages. PIN CONNECTION DIAGRAM D, N, AND PW PACKAGES (TOP VIEW) GND PKLMT CAOUT CAI MOUT IAC VAOUT VFF 1 16 2 15 3 14 4 13 5 12 6 11 7 10 8 9 DRVOUT VCC CT SS RT VSENSE OVP/EN VREF AVAILABLE OPTIONS TABLE PACKAGE DEVICES SOIC (D) PACKAGE(1) TSSOP (PW) PACKAGE(1) PDIP (N) PACKAGE TA = TJ Turn-on Threshold 16 V Turn-on Threshold 10.2 V Turn-on Threshold 16 V Turn-on Threshold 10.2 V Turn-on Threshold 16 V Turn-on Threshold 10.2 V -40C to 85C UCC2817AD UCC2818AD UCC2817AN UCC2818AN UCC2817APW UCC2818APW 0C to 70C UCC3817AD UCC3818AD UCC3817AN UCC3818AN UCC3817APW UCC3818APW NOTES: (1) The D and PW packages are available taped and reeled. Add R suffix to the device type (e.g. UCC3817ADR) to order quantities of 2,500 devices per reel (D package) and 2,000 devices per reel (for PW package). Bulk quantities are 40 units (D package) and 90 units (PW package) per tube. THERMAL RESISTANCE TABLE PACKAGE jc(C/W) ja(C/W) SOIC-16 (D) 22 PDIP-16 (N) 12 14 (2) 40 to 70 (1) 25 to 50 (1) TSSOP-16 (PW) 123 to 147 (2) NOTES: (1) Specified ja (junction to ambient) is for devices mounted to 5-inch2 FR4 PC board with one ounce copper where noted. When resistance range is given, lower values are for 5 inch2 aluminum PC board. Test PWB was 0.062 inch thick and typically used 0.635-mm trace widths for power packages and 1.3-mm trace widths for non-power packages with a 100-mil x 100-mil probe land area at the end of each trace. (2) Modeled data. If value range given for ja, lower value is for 3x3 inch. 1 oz internal copper ground plane, higher value is for 1x1-inch. ground plane. All model data assumes only one trace for each non-fused lead. 2 www.ti.com SLUS577C - SEPTEMBER, 2003 - REVISED MARCH 2009 ABSOLUTE MAXIMUM RATINGS over operating free-air temperature (unless otherwise noted) UCCx81xA UNIT Supply voltage VCC 18 V Supply current ICC 20 mA Gate drive current, continuous 0.2 Gate drive current 1.2 Input voltage, CAI, MOUT, SS A 8 Input voltage, PKLMT 5 Input voltage, VSENSE, OVP/EN 10 Input current, RT, IAC, PKLMT 10 Input current, VCC (no switching) 20 Maximum negative voltage, DRVOUT, PKLMT, MOUT Power dissipation V mA -0.5 V 1 W Junction temperature, TJ -55 to 150 Storage temperature, Tstg -65 to 150 Lead temperature, Tsol (soldering, 10 seconds) C C 300 Power dissipation 1 W Stresses beyond those listed under "absolute maximum ratings" may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated under recommended operating conditions is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability. ELECTRICAL CHARACTERISTICS TA = 0C to 70C for the UCC3817A and TA = -40C to 85C for the UCC2817A, TA = TJ, VCC = 12 V, RT = 22 k, CT = 270 pF, (unless otherwise noted) PARAMETER TEST CONDITIONS MIN TYP MAX UNITS 150 300 A 4 6 mA 16.6 Supply Current Section Supply current, off VCC = (VCC turn-on threshold -0.3 V) Supply current, on VCC = 12 V, No load on DRVOUT 2 UVLO Section VCC turn-on threshold (UCCx817) 15.4 16 VCC turn-off threshold (UCCx817) 9.4 9.7 UVLO hysteresis (UCCx817) 5.8 6.3 Maximum shunt voltage (UCCx817) 15.4 17 17.5 VCC turn-on threshold (UCCx818) IVCC = 10 mA 9.7 10.2 10.8 VCC turn-off threshold (UCCx818) 9.4 9.7 UVLO hysteresis (UCCx818) 0.3 0.5 7.387 7.5 7.613 7.369 7.5 7.631 50 200 V Voltage Amplifier Section Input voltage TA = 0C to 70C TA = -40C to 85C VSENSE bias current Open loop gain VSENSE = VREF, VAOUT = 2 V to 5 V High-level output voltage IL = -150 A IL = 150 A Low-level output voltage VAOUT = 2.5 V www.ti.com V nA 50 90 5.3 5.5 5.6 dB V 0 50 150 mV 3 SLUS577C - SEPTEMBER, 2003 - REVISED MARCH 2009 ELECTRICAL CHARACTERISTICS TA = 0C to 70C for the UCC3817A and TA = -40C to 85C for the UCC2817A, TA = TJ, VCC = 12 V, RT = 22 k, CT = 270 pF, (unless otherwise noted) PARAMETER TEST CONDITIONS MIN TYP MAX UNITS VREF +0.48 VREF +0.50 VREF +0.52 V Hysteresis 300 500 600 Enable threshold 1.7 1.9 2.1 Enable hysteresis 0.1 0.2 0.3 Over Voltage Protection and Enable Section Over voltage reference mV V Current Amplifier Section Input offset voltage Input bias current Input offset current Open loop gain Common-mode rejection ratio High-level output voltage Low-level output voltage Gain bandwidth product VCM = 0 V, VCM = 0 V, VCAOUT = 3 V VCAOUT = 3 V VCM = 0 V, VCM = 0 V, VCAOUT = 3 V VCAOUT = 2 V to 5 V 90 VCM = 0 V to 1.5 V, IL = -120 A VCAOUT = 3 V 60 80 5.6 6.5 6.8 0.1 0.2 0.5 IL = 1 mA (1) -3.5 0 2.5 -50 -100 25 100 mV nA dB 2.5 V MHz Voltage Reference Section Input voltage Load regulation TA = 0C to 70C TA = -40C to 85C Line regulation IREF = 1 mA to 2 mA VCC = 10.8 V to 15 V(2) Short-circuit current VREF = 0 V 7.387 7.5 7.613 7.369 7.5 7.631 0 10 0 10 V mV -20 -25 -50 mA 85 100 115 kHz Voltage stability TA = 25C VCC = 10.8 V to 15 V -1 1 Total variation Line, temp 80 120 Oscillator Section Initial accuracy % kHz Ramp peak voltage 4.5 5 5.5 Ramp amplitude voltage (peak to peak) 3.5 4 4.5 15 mV 350 500 ns V Peak Current Limit Section PKLMT reference voltage -15 PKLMT propagation delay 150 NOTES: 1. Ensured by design, not production tested. 2. Reference variation for VCC < 10.8 V is shown in Figure 8. 4 www.ti.com SLUS577C - SEPTEMBER, 2003 - REVISED MARCH 2009 ELECTRICAL CHARACTERISTICS TA = 0C to 70C for the UCC3817A and TA = -40C to 85C for the UCC2817A, TA = TJ, VCC = 12 V, RT = 22 k, CT = 270 pF, (unless otherwise noted) PARAMETER TEST CONDITIONS MIN TYP MAX UNITS Multiplier Section IMOUT, high line, low power output current, (0C to 85C) IAC = 500 A, VFF = 4.7 V, VAOUT = 1.25 V 0 -6 -20 IMOUT, high line, low power output current, (-40C to 85C) IAC = 500 A, VFF = 4.7 V, VAOUT = 1.25 V 0 -6 -23 IMOUT, high line, high power output current IAC = 500 A, VFF = 4.7 V, VAOUT = 5 V -70 -90 -105 IMOUT, low line, low power output current IAC = 150 A, VFF = 1.4 V, VAOUT = 1.25 V -10 -19 -50 IMOUT, low line, high power output current IAC = 150 A, VFF = 1.4 V, VAOUT = 5 V -268 -300 -345 IMOUT, IAC limited output current Gain constant (K) IAC = 150 A, IAC = 300 A, VFF = 1.3 V, VFF = 3 V, VAOUT = 5 V -250 -300 -400 0.5 1 1.5 VFF = 1.4 V, VFF = 4.7 V, VAOUT = 0.25 V 0 -2 IMOUT, zero current IAC = 150 A, IAC = 500 A, VAOUT = 0.25 V 0 -2 IMOUT, zero current, (0C to 85C) IMOUT, zero current, (-40C to 85C) IAC = 500 A, IAC = 500 A, VFF = 4.7 V, VFF = 4.7 V, VAOUT = 0.5 V 0 -3 Power limit (IMOUT x VFF) IAC = 150 A, VFF = 1.4 V, VAOUT = 5 V VAOUT = 2.5 V VAOUT = 0.5 V A 1/V A A 0 -3.5 -375 -420 -485 W -140 -150 -160 A -6 -10 -16 A 9 12 4 10 25 50 10 50 95% 99% Feed-Forward Section VFF output current IAC = 300 A Soft Start Section SS charge current Gate Driver Section Pullup resistance Pulldown resistance IO = -100 mA to -200 mA IO = 100 mA Output rise time CL = 1 nF, RL = 10 , Output fall time CL = 1 nF, RL = 10 , VDRVOUT = 0.7 V to 9.0 V VDRVOUT = 9.0 V to 0.7 V Maximum duty cycle Minimum controlled duty cycle 93% At 100 kHz ns 2% Zero Power Section Zero power comparator threshold Measured on VAOUT www.ti.com 0.20 0.33 0.50 V 5 SLUS577C - SEPTEMBER, 2003 - REVISED MARCH 2009 PIN ASSIGNMENTS TERMINAL NAME I/O NO. DESCRIPTION CAI 4 I Current amplifier noninverting input CAOUT 3 O Current amplifier output CT 14 I Oscillator timing capacitor DRVOUT 16 O Gate drive GND 1 - Ground IAC 6 I Current proportional to input voltage MOUT 5 I/O OVP/EN 10 I Over-voltage/enable PKLMT 2 I PFC peak current limit RT 12 I Oscillator charging current SS 13 I Soft-start VAOUT 7 O Voltage amplifier output VCC 15 I Positive supply voltage VFF 8 I Feed-forward voltage VSENSE 11 I Voltage amplifier inverting input VREF 9 O Voltage reference output Multiplier output and current amplifier inverting input Pin Descriptions CAI: Place a resistor between this pin and the GND side of current sense resistor. This input and the inverting input (MOUT) remain functional down to and below GND. CAOUT: This is the output of a wide bandwidth operational amplifier that senses line current and commands the PFC pulse-width modulator (PWM) to force the correct duty cycle. Compensation components are placed between CAOUT and MOUT. CT: A capacitor from CT to GND sets the PWM oscillator frequency according to: f[ RT0.6CT The lead from the oscillator timing capacitor to GND should be as short and direct as possible. DRVOUT: The output drive for the boost switch is a totem-pole MOSFET gate driver on DRVOUT. To avoid the excessive overshoot of the DRVOUT while driving a capacitive load, a series gate current-limiting/damping resistor is recommended to prevent interaction between the gate impedance and the output driver. The value of the series gate resistor is based on the pulldown resistance (Rpulldown which is 4 typical), the maximum VCC voltage (VCC), and the required maximum gate drive current (IMAX). Using the equation below, a series gate resistance of resistance 11 would be required for a maximum VCC voltage of 18 V and for 1.2 A of maximum sink current. The source current will be limited to approximately 900 mA (based on the Rpullup of 9- typical). R GATE + VCC * I MAX R pulldown I MAX GND: All voltages measured with respect to ground. VCC and REF should be bypassed directly to GND with a 0.1-F or larger ceramic capacitor. 6 www.ti.com SLUS577C - SEPTEMBER, 2003 - REVISED MARCH 2009 Pin Descriptions (cont.) IAC: This input to the analog multiplier is a current proportional to instantaneous line voltage. The multiplier is tailored for very low distortion from this current input (IIAC) to multiplier output. The recommended maximum IIAC is 500 A. MOUT: The output of the analog multiplier and the inverting input of the current amplifier are connected together at MOUT. As the multiplier output is a current, this is a high-impedance input so the amplifier can be configured as a differential amplifier. This configuration improves noise immunity and allows for the leading-edge modulation operation. The multiplier output current is limited to 2 I IAC. The multiplier output current is given by the equation: I MOUT + I IAC (V VAOUT * 1) V VFF 2 K where K + 1 is the multiplier gain constant. V OVP/EN: A window comparator input that disables the output driver if the boost output voltage is a programmed level above the nominal or disables both the PFC output driver and resets SS if pulled below 1.9 V (typ). PKLMT: The threshold for peak limit is 0 V. Use a resistor divider from the negative side of the current sense resistor to VREF to level shift this signal to a voltage level defined by the value of the sense resistor and the peak current limit. Peak current limit is reached when PKLMT voltage falls below 0 V. RT: A resistor from RT to GND is used to program oscillator charging current. A resistor between 10 k and 100 k is recommended. Nominal voltage on this pin is 3 V. SS: VSS is discharged for VVCC low conditions. When enabled, SS charges an external capacitor with a current source. This voltage is used as the voltage error signal during start-up, enabling the PWM duty cycle to increase slowly. In the event of a VVCC dropout, the OVP/EN is forced below 1.9 V (typ), SS quickly discharges to disable the PWM. Note: In an open-loop test circuit, grounding the SS pin does not ensure 0% duty cycle. Please see the application section for details. VAOUT: This is the output of the operational amplifier that regulates output voltage. The voltage amplifier output is internally limited to approximately 5.5 V to prevent overshoot. VCC: Connect to a stable source of at least 20 mA between 10 V and 17 V for normal operation. Bypass VCC directly to GND to absorb supply current spikes required to charge external MOSFET gate capacitances. To prevent inadequate gate drive signals, the output devices are inhibited unless VVCC exceeds the upper under-voltage lockout voltage threshold and remains above the lower threshold. VFF: The RMS voltage signal generated at this pin by mirroring 1/2 of the IIAC into a single pole external filter. At low line, the VFF voltage should be 1.4 V. VSENSE: This is normally connected to a compensation network and to the boost converter output through a divider network. VREF: VREF is the output of an accurate 7.5-V voltage reference. This output is capable of delivering 20 mA to peripheral circuitry and is internally short-circuit current limited. VREF is disabled and remains at 0 V when VVCC is below the UVLO threshold. Bypass VREF to GND with a 0.1-F or larger ceramic capacitor for best stability. Please refer to Figures 8 and 9 for VREF line and load regulation characteristics. www.ti.com 7 SLUS577C - SEPTEMBER, 2003 - REVISED MARCH 2009 APPLICATION INFORMATION The UCC3817A is a BiCMOS average current mode boost controller for high power factor, high efficiency preregulator power supplies. Figure 1 shows the UCC3817A in a 250-W PFC preregulator circuit. Off-line switching power converters normally have an input current that is not sinusoidal. The input current waveform has a high harmonic content because current is drawn in pulses at the peaks of the input voltage waveform. An active power factor correction circuit programs the input current to follow the line voltage, forcing the converter to look like a resistive load to the line. A resistive load has 0 phase displacement between the current and voltage waveforms. Power factor can be defined in terms of the phase angle between two sinusoidal waveforms of the same frequency: PF + cos Q (1) Therefore, a purely resistive load would have a power factor of 1. In practice, power factors of 0.999 with THD (total harmonic distortion) of less than 3% are possible with a well-designed circuit. Following guidelines are provided to design PFC boost converters using the UCC3817A. NOTE: Schottky diodes, D5 and D6, are required to protect the PFC controller from electrical over stress during system power up. C10 1 F R16 100 C11 1 F VCC R21 383k R15 24k R13 383k D7 D8 L1 1mH IAC R18 24k AC2 + C14 1.5 F 400V VLINE 85-270 VAC VO D1 8A, 600V F1 D2 6A, 600V C13 0.47 F 600V R14 0.25 3W 6A 600V - R17 20 UCC3817A R9 4.02k R12 2k VOUT C12 385V-DC 220 F 450V Q1 IRFP450 D3 AC1 R10 4.02k 1 GND DRVOUT 16 2 PKLIMIT 3 CAOUT 4 CAI 5 MOUT CT 14 6 IAC SS 13 RT 12 VSENSE 11 D4 VCC VCC D5 R11 10k VREF R8 12k C3 1 F CER 15 C2 100 F AI EI C1 560pF C9 1.2nF C4 0.01 F C8 270pF R1 12k D6 C7 150nF R7 100k C15 2.2 F 7 VAOUT 8 VFF R3 20k R19 499k VO R20 274k R4 249k R2 499k C6 2.2 F OVP/EN 10 R6 30k C5 1F VREF 9 VREF Figure 1. Typical Application Circuit 8 www.ti.com R5 10k UDG-98183 SLUS577C - SEPTEMBER, 2003 - REVISED MARCH 2009 APPLICATION INFORMATION Power Stage LBOOST : The boost inductor value is determined by: L BOOST + VIN(min) (DI D fs) (2) where D is the duty cycle, I is the inductor ripple current and fS is the switching frequency. For the example circuit a switching frequency of 100 kHz, a ripple current of 875 mA, a maximum duty cycle of 0.688 and a minimum input voltage of 85 VRMS gives us a boost inductor value of about 1 mH. The values used in this equation are at the peak of low line, where the inductor current and its ripple are at a maximum. COUT : Two main criteria, the capacitance and the voltage rating, dictate the selection of the output capacitor. The value of capacitance is determined by the holdup time required for supporting the load after input ac voltage is removed. Holdup is the amount of time that the output stays in regulation after the input has been removed. For this circuit, the desired holdup time is approximately 16 ms. Expressing the capacitor value in terms of output power, output voltage, and holdup time gives the equation: C OUT + 2 P OUT Dt VOUT2 * VOUT(min)2 (3) In practice, the calculated minimum capacitor value may be inadequate because output ripple voltage specifications limit the amount of allowable output capacitor ESR. Attaining a sufficiently low value of ESR often necessitates the use of a much larger capacitor value than calculated. The amount of output capacitor ESR allowed can be determined by dividing the maximum specified output ripple voltage by the inductor ripple current. In this design holdup time was the dominant determining factor and a 220-F, 450-V capacitor was chosen for the output voltage level of 385 VDC at 250 W. www.ti.com 9 SLUS577C - SEPTEMBER, 2003 - REVISED MARCH 2009 APPLICATION INFORMATION Power switch selection: As in any power supply design, tradeoffs between performance, cost and size have to be made. When selecting a power switch, it can be useful to calculate the total power dissipation in the switch for several different devices at the switching frequencies being considered for the converter. Total power dissipation in the switch is the sum of switching loss and conduction loss. Switching losses are the combination of the gate charge loss, COSS loss and turnon and turnoff losses: P GATE + Q GATE P COSS + 1 2 V GATE V 2 OFF C OSS P ON ) P OFF + 1 2 fS V OFF IL (4) fS (5) tON ) t OFF fS (6) where QGATE is the total gate charge, VGATE is the gate drive voltage, fS is the clock frequency, COSS is the drain source capacitance of the MOSFET, IL is the peak inductor current, tON and tOFF are the switching times (estimated using device parameters RGATE, QGD and VTH) and VOFF is the voltage across the switch during the off time, in this case VOFF = VOUT. Conduction loss is calculated as the product of the RDS(on) of the switch (at the worst case junction temperature) and the square of RMS current: P COND + R DS(on) K I 2 RMS (7) where K is the temperature factor found in the manufacturer's RDS(on) vs. junction temperature curves. Calculating these losses and plotting against frequency gives a curve that enables the designer to determine either which manufacturer's device has the best performance at the desired switching frequency, or which switching frequency has the least total loss for a particular power switch. For this design example an IRFP450 HEXFET from International Rectifier was chosen because of its low RDS(on) and its VDSS rating. The IRFP450's RDS(on) of 0.4 and the maximum VDSS of 500 V made it an ideal choice. An excellent review of this procedure can be found in the Unitrode Power Supply Design Seminar SEM1200, Topic 6, Design Review: 140 W, [Multiple Output High Density DC/DC Converter]. Softstart The softstart circuitry is used to prevent overshoot of the output voltage during start up. This is accomplished by bringing up the voltage amplifier's output (VVAOUT) slowly which allows for the PWM duty cycle to increase slowly. Please use the following equation to select a capacitor for the softstart pin. In this example tDELAY is equal to 7.5 ms, which would yield a CSS of 10 nF. C SS + 10 mA t DELAY 7.5 V (8) In an open-loop test circuit, shorting the softstart pin to ground does not ensure 0% duty cycle. This is due to the current amplifiers input offset voltage, which could force the current amplifier output high or low depending on the polarity of the offset voltage. However, in the typical application there is sufficient amount of inrush and bias current to overcome the current amplifier's offset voltage. 10 www.ti.com SLUS577C - SEPTEMBER, 2003 - REVISED MARCH 2009 APPLICATION INFORMATION Multiplier The output of the multiplier of the UCC3817A is a signal representing the desired input line current. It is an input to the current amplifier, which programs the current loop to control the input current to give high power factor operation. As such, the proper functioning of the multiplier is key to the success of the design. The inputs to the multiplier are VAOUT, the voltage amplifier error signal, IIAC, a representation of the input rectified ac line voltage, and an input voltage feedforward signal, VVFF. The output of the multiplier, IMOUT, can be expressed as: I MOUT + I IAC VVAOUT * 1 K V VFF 2 (9) where K is a constant typically equal to 1 . V The electrical characteristics table covers all the required operating conditions for designing with the multiplier. Additionally, curves in Figures 10, 11, and 12 provide typical multiplier characteristics over its entire operating range. The IIAC signal is obtained through a high-value resistor connected between the rectified ac line and the IAC pin of the UCC3817A/18A. This resistor (RIAC) is sized to give the maximum IIAC current at high line. For the UCC3817A/18A the maximum IIAC current is about 500 A. A higher current than this can drive the multiplier out of its linear range. A smaller current level is functional, but noise can become an issue, especially at low input line. Assuming a universal line operation of 85 VRMS to 265 VRMS gives a RIAC value of 750 k. Because of voltage rating constraints of standard 1/4-W resistor, use a combination of lower value resistors connected in series to give the required resistance and distribute the high voltage amongst the resistors. For this design example two 383-k resistors were used in series. The current into the IAC pin is mirrored internally to the VFF pin where it is filtered to produce a voltage feed forward signal proportional to line voltage. The VFF voltage is used to keep the power stage gain constant; and to provid input power limiting. Please refer to Texas Instruments application note SLUA196 for detailed explanation on how the VFF pin provides power limiting. The following equation can be used to size the VFF resistor (RVFF) to provide power limiting where VIN(min) is the minimum RMS input voltage and RIAC is the total resistance connected between the IAC pin and the rectified line voltage. R VFF + 1.4 V V IN(min) 0.9 [ 30 kW 2 RIAC (10) www.ti.com 11 SLUS577C - SEPTEMBER, 2003 - REVISED MARCH 2009 APPLICATION INFORMATION Because the VFF voltage is generated from line voltage it needs to be adequately filtered to reduce total harmonic distortion caused by the 120 Hz rectified line voltage. Refer to Unitrode Power Supply Design Seminar, SEM-700 Topic 7, [Optimizing the Design of a High Power Factor Preregulator.] A single pole filter was adequate for this design. Assuming that an allocation of 1.5% total harmonic distortion from this input is allowed, and that the second harmonic ripple is 66% of the input ac line voltage, the amount of attenuation required by this filter is: 1.5 % + 0. 022 66 % (11) With a ripple frequency (fR) of 120 Hz and an attenuation of 0.022 requires that the pole of the filter (fP) be placed at: f P + 120 Hz 0.022 [ 2.6 Hz (12) The following equation can be used to select the filter capacitor (CVFF) required to produce the desired low pass filter. C VFF + 2 p 1 R VFF fP [ 2.2 mF (13) The RMOUT resistor is sized to match the maximum current through the sense resistor to the maximum multiplier current. The maximum multiplier current, or IMOUT(max), can be determined by the equation: I MOUT(max) + I IAC@V IN(min) K VVAOUT(max) * 1 V V VFF 2 (min) (14) IMOUT(max) for this design is approximately 315 A. The RMOUT resistor can then be determined by: R MOUT + V RSENSE I MOUT(max) (15) In this example VRSENSE was selected to give a dynamic operating range of 1.25 V, which gives an RMOUT of roughly 3.91 k. 12 www.ti.com SLUS577C - SEPTEMBER, 2003 - REVISED MARCH 2009 APPLICATION INFORMATION Voltage Loop The second major source of harmonic distortion is the ripple on the output capacitor at the second harmonic of the line frequency. This ripple is fed back through the error amplifier and appears as a 3rd harmonic ripple at the input to the multiplier. The voltage loop must be compensated not just for stability but also to attenuate the contribution of this ripple to the total harmonic distortion of the system. (refer to Figure 2). Cf VOUT CZ Rf R IN - RD + VREF Figure 2. Voltage Amplifier Configuration The gain of the voltage amplifier, GVA, can be determined by first calculating the amount of ripple present on the output capacitor. The peak value of the second harmonic voltage is given by the equation: V OPK + P IN 2 p fR C OUT V OUT (16) In this example VOPK is equal to 3.91 V. Assuming an allowable contribution of 0.75% (1.5% peak to peak) from the voltage loop to the total harmonic distortion budget we set the gain equal to: G VA + DVVAOUT (0.015) 2 V OPK (17) where VVAOUT is the effective output voltage range of the error amplifier (5 V for the UCC3817A). The network needed to realize this filter is comprised of an input resistor, RIN, and feedback components Cf, CZ, and Rf. The value of RIN is already determined because of its function as one half of a resistor divider from VOUT feeding back to the voltage amplifier for output voltage regulation. In this case the value was chosen to be 1 M. This high value was chosen to reduce power dissipation in the resistor. In practice, the resistor value would be realized by the use of two 500-k resistors in series because of the voltage rating constraints of most standard 1/4-W resistors. The value of Cf is determined by the equation: Cf + 2 p fR 1 G VA R IN (18) www.ti.com 13 SLUS577C - SEPTEMBER, 2003 - REVISED MARCH 2009 APPLICATION INFORMATION In this example Cf equals 150 nF. Resistor Rf sets the dc gain of the error amplifier and thus determines the frequency of the pole of the error amplifier. The location of the pole can be found by setting the gain of the loop equation to one and solving for the crossover frequency. The frequency, expressed in terms of input power, can be calculated by the equation: 2 f VI + P IN (2 p)2 DV VAOUT V OUT R IN C OUT Cf (19) fVI for this converter is 10 Hz. A derivation of this equation can be found in the Unitrode Power Supply Design Seminar SEM1000, Topic 1, [A 250-kHz, 500-W Power Factor Correction Circuit Employing Zero Voltage Transitions]. Solving for Rf becomes: Rf + 1 f VI 2 p C f (20) or Rf equals 100 k. Due to the low output impedance of the voltage amplifier, capacitor CZ was added in series with RF to reduce loading on the voltage divider. To ensure the voltage loop crossed over at fVI, CZ was selected to add a zero at a 10th of fVI. For this design a 2.2-F capacitor was chosen for CZ. The following equation can be used to calculate CZ. CZ + 2 1 fVI p 10 Rf (21) Current Loop The gain of the power stage is: G ID(s) + VOUT s R SENSE L BOOST V P (22) RSENSE has been chosen to give the desired differential voltage for the current sense amplifier at the desired current limit point. In this example, a current limit of 4 A and a reasonable differential voltage to the current amp of 1 V gives a RSENSE value of 0.25 . VP in this equation is the voltage swing of the oscillator ramp, 4 V for the UCC3817A. Setting the crossover frequency of the system to 1/10th of the switching frequency, or 10 kHz, requires a power stage gain at that frequency of 0.383. In order for the system to have a gain of 1 at the crossover frequency, the current amplifier needs to have a gain of 1/GID at that frequency. GEA, the current amplifier gain is then: G EA + 1 + 1 + 2.611 0.383 G ID 14 (23) www.ti.com SLUS577C - SEPTEMBER, 2003 - REVISED MARCH 2009 APPLICATION INFORMATION RI is the RMOUT resistor, previously calculated to be 3.9 k. (refer to Figure 3). The gain of the current amplifier is Rf/RI, so multiplying RI by GEA gives the value of Rf, in this case approximately 12 k. Setting a zero at the crossover frequency and a pole at half the switching frequency completes the current loop compensation. CZ + 2 p 1 Rf fC (24) 1 CP + 2 p Rf fs (25) 2 C P C Rf Z RI - CAOUT + Figure 3. Current Loop Compensation The UCC3817A current amplifier has the input from the multiplier applied to the inverting input. This change in architecture from previous Texas Instruments PFC controllers improves noise immunity in the current amplifier. It also adds a phase inversion into the control loop. The UCC3817A takes advantage of this phase inversion to implement leading-edge duty cycle modulation. Synchronizing a boost PFC controller to a downstream dc-to-dc controller reduces the ripple current seen by the bulk capacitor between stages, reducing capacitor size and cost and reducing EMI. This is explained in greater detail in a following section. The UCC3817A current amplifier configuration is shown in Figure 4. L BOOST V OUT - R SENSE Q BOOST + Zf MULT CA PWM COMPARATOR - - + + Figure 4. UCC3817A Current Amplifier Configuration www.ti.com 15 SLUS577C - SEPTEMBER, 2003 - REVISED MARCH 2009 APPLICATION INFORMATION Start Up The UCC3818A version of the device is intended to have VCC connected to a 12-V supply voltage. The UCC3817A has an internal shunt regulator enabling the device to be powered from bootstrap circuitry as shown in the typical application circuit of Figure 1. The current drawn by the UCC3817A during undervoltage lockout, or start-up current, is typically 150 A. Once VCC is above the UVLO threshold, the device is enabled and draws 4 mA typically. A resistor connected between the rectified ac line voltage and the VCC pin provides current to the shunt regulator during power up. Once the circuit is operational, the bootstrap winding of the inductor provides the VCC voltage. Sizing of the start-up resistor is determined by the start-up time requirement of the system design. I C + C DV Dt R+ (26) (0.9) V RMS IC (27) Where IC is the charge current, C is the total capacitance at the VCC pin, V is the UVLO threshold and t is the allowed start-up time. Assuming a 1 second allowed start-up time, a 16-V UVLO threshold, and a total VCC capacitance of 100 F, a resistor value of 51 k is required at a low line input voltage of 85 VRMS. The IC start-up current is sufficiently small as to be ignored in sizing the start-up resistor. Capacitor Ripple Reduction For a power system where the PFC boost converter is followed by a dc-to-dc converter stage, there are benefits to synchronizing the two converters. In addition to the usual advantages such as noise reduction and stability, proper synchronization can significantly reduce the ripple currents in the boost circuit's output capacitor. Figure 5 helps illustrate the impact of proper synchronization by showing a PFC boost converter together with the simplified input stage of a forward converter. The capacitor current during a single switching cycle depends on the status of the switches Q1 and Q2 and is shown in Figure 6. It can be seen that with a synchronization scheme that maintains conventional trailing-edge modulation on both converters, the capacitor current ripple is highest. The greatest ripple current cancellation is attained when the overlap of Q1 offtime and Q2 ontime is maximized. One method of achieving this is to synchronize the turnon of the boost diode (D1) with the turnon of Q2. This approach implies that the boost converter's leading edge is pulse width modulated while the forward converter is modulated with traditional trailing edge PWM. The UCC3817A is designed as a leading edge modulator with easy synchronization to the downstream converter to facilitate this advantage. Table 1 compares the ICB(rms) for D1/Q2 synchronization as offered by UCC3817A vs. the ICB(rms) for the other extreme of synchronizing the turnon of Q1 and Q2 for a 200-W power system with a VBST of 385 V. 16 www.ti.com SLUS577C - SEPTEMBER, 2003 - REVISED MARCH 2009 APPLICATION INFORMATION UDG-97130-1 Figure 5. Simplified Representation of a 2-Stage PFC Power Supply UDG-97131 Figure 6. Timing Waveforms for Synchronization Scheme www.ti.com 17 SLUS577C - SEPTEMBER, 2003 - REVISED MARCH 2009 APPLICATION INFORMATION Table 1 illustrates that the boost capacitor ripple current can be reduced by about 50% at nominal line and about 30% at high line with the synchronization scheme facilitated by the UCC3817A. Figure 7 shows the suggested technique for synchronizing the UCC3817A to the downstream converter. With this technique, maximum ripple reduction as shown in Figure 6 is achievable. The output capacitance value can be significantly reduced if its choice is dictated by ripple current or the capacitor life can be increased as a result. In cost sensitive designs where holdup time is not critical, this is a significant advantage. Table 1. Effects of Synchronization on Boost Capacitor Current VIN = 85 V Q1/Q2 D1/Q2 VIN = 120 V Q1/Q2 D1/Q2 VIN = 240 V Q1/Q2 D1/Q2 0.35 1.491 A 0.835 A 1.341 A 0.663 A 1.024 A 0.731 A 0.45 1.432 A 0.93 A 1.276 A 0.664 A 0.897 A 0.614 A D(Q2) An alternative method of synchronization to achieve the same ripple reduction is possible. In this method, the turnon of Q1 is synchronized to the turnoff of Q2. While this method yields almost identical ripple reduction and maintains trailing edge modulation on both converters, the synchronization is much more difficult to achieve and the circuit can become susceptible to noise as the synchronizing edge itself is being modulated. Gate Drive From Down Stream PWM C1 UCC3817A D2 CT D1 CT RT RT Figure 7. Synchronizing the UCC3817A to a Down-Stream Converter 18 www.ti.com SLUS577C - SEPTEMBER, 2003 - REVISED MARCH 2009 APPLICATION INFORMATION REFERENCE VOLTAGE vs REFERENCE CURRENT REFERENCE VOLTAGE vs SUPPLY VOLTAGE 7.510 VREF - Reference Voltage - V VREF - Reference Voltage - V 7.60 7.55 7.50 7.45 7.505 7.500 7.495 7.490 7.40 9 10 11 12 13 0 14 5 15 20 25 IVREF - Reference Current - mA VCC - Supply Voltage - V Figure 8 Figure 9 MULTIPLIER OUTPUT CURRENT vs VOLTAGE ERROR AMPLIFIER OUTPUT MULTIPLIER GAIN vs VOLTAGE ERROR AMPLIFIER OUTPUT 1.5 350 IAC = 150 A VFF = 1.4 V 300 1.3 IAC = 150 A 250 200 IAC = 300 A VFF = 3.0 V 150 100 Multiplier Gain - K IMOUT - Multiplier Output Current - A 10 1.1 0.9 IAC = 300 A IAC = 500 A 0.7 50 IAC = 500 A VFF = 4.7 V 0.5 0 0.0 1.0 2.0 3.0 4.0 1.0 5.0 2.0 3.0 4.0 5.0 VAOUT - Voltage Error Amplifier Output - V VAOUT - Voltage Error Amplifier Output - V Figure 10 Figure 11 www.ti.com 19 SLUS577C - SEPTEMBER, 2003 - REVISED MARCH 2009 APPLICATION INFORMATION MULTIPLIER CONSTANT POWER PERFORMANCE (VFF x IMOUT) - W 500 400 VAOUT = 5 V 300 VAOUT = 4 V 200 VAOUT = 3 V 100 VAOUT = 2 V 0 0.0 1.0 2.0 3.0 4.0 5.0 VFF - Feedforward Voltage - V Figure 12 References and Resources: Application Note, Differences Between UCC3817A/18A/19A and UCC3817/18/19, Texas Instruments Literature Number SLUA294 Evaluation Module, UCC3817EVM, 385V, 250W PFC Boost Converter User's Guide, UCC3817 BiCMOS Power Factor Preregulator Evaluation Board, Texas Instruments Literature Number SLUU077 Application Note, Synchronizing a PFC Controller from a Down Stream Controller Gate Drive, Texas Instruments Literature Number SLUA245 Seminar topic, High Power Factor Switching Preregulator Design Optimization, L.H. Dixon, SEM-700,1990. Seminar topic, High Power Factor Preregulator for Off-line Supplies, L.H. Dixon, SEM-600, 1988. Related Products DEVICE DESCRIPTION UC3854 PFC controller UC3854A/B Improved PFC controller UC3855A/B High performance soft switching PFC controller UCC38050/1 Transition mode PFC controller UCC3819 Tracking boost PFC controller UCC28510/11/12/13 Advanced PFC+PWM combo controller UCC28514/15/16/17 Advanced PFC+PWM combo controller NOTES: (1). Critical conduction mode (2). Average current mode 20 www.ti.com CONTROL METHOD ACM(2) TYPICAL POWER LEVEL ACM(2) ACM(2) 200 W to 2 kW+ CRM(1) ACM(2) 50 W to 400 W ACM(2) ACM(2) 75 W to 1kW+ 200 W to 2 kW+ 400 W to 2 kW+ 75 W to 2 kW+ 75 W to 1kW+ PACKAGE OPTION ADDENDUM www.ti.com 30-Jul-2011 PACKAGING INFORMATION Orderable Device Status (1) Package Type Package Drawing Pins Package Qty Eco Plan (2) Lead/ Ball Finish MSL Peak Temp (3) UCC2817AD ACTIVE SOIC D 16 40 Green (RoHS & no Sb/Br) CU NIPDAU Level-1-260C-UNLIM UCC2817ADG4 ACTIVE SOIC D 16 40 Green (RoHS & no Sb/Br) CU NIPDAU Level-1-260C-UNLIM UCC2817ADR ACTIVE SOIC D 16 2500 Green (RoHS & no Sb/Br) CU NIPDAU Level-1-260C-UNLIM UCC2817ADRG4 ACTIVE SOIC D 16 2500 Green (RoHS & no Sb/Br) CU NIPDAU Level-1-260C-UNLIM UCC2817AN ACTIVE PDIP N 16 25 Green (RoHS & no Sb/Br) CU NIPDAU N / A for Pkg Type UCC2817ANG4 ACTIVE PDIP N 16 25 Green (RoHS & no Sb/Br) CU NIPDAU N / A for Pkg Type UCC2817APW ACTIVE TSSOP PW 16 90 Green (RoHS & no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR UCC2817APWG4 ACTIVE TSSOP PW 16 90 Green (RoHS & no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR UCC2817APWR ACTIVE TSSOP PW 16 2000 Green (RoHS & no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR UCC2817APWRG4 ACTIVE TSSOP PW 16 2000 Green (RoHS & no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR UCC2818AD ACTIVE SOIC D 16 40 Green (RoHS & no Sb/Br) CU NIPDAU Level-1-260C-UNLIM UCC2818ADG4 ACTIVE SOIC D 16 40 Green (RoHS & no Sb/Br) CU NIPDAU Level-1-260C-UNLIM UCC2818ADR ACTIVE SOIC D 16 2500 Green (RoHS & no Sb/Br) CU NIPDAU Level-1-260C-UNLIM UCC2818ADR/1 ACTIVE SOIC D 16 2500 Green (RoHS & no Sb/Br) CU NIPDAU Level-1-260C-UNLIM UCC2818ADRG4 ACTIVE SOIC D 16 2500 Green (RoHS & no Sb/Br) CU NIPDAU Level-1-260C-UNLIM UCC2818AN ACTIVE PDIP N 16 25 Green (RoHS & no Sb/Br) CU NIPDAU N / A for Pkg Type UCC2818ANG4 ACTIVE PDIP N 16 25 Green (RoHS & no Sb/Br) CU NIPDAU N / A for Pkg Type Addendum-Page 1 Samples (Requires Login) PACKAGE OPTION ADDENDUM www.ti.com Orderable Device 30-Jul-2011 Status (1) Package Type Package Drawing Pins Package Qty Eco Plan (2) Lead/ Ball Finish MSL Peak Temp (3) UCC2818APW ACTIVE TSSOP PW 16 90 Green (RoHS & no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR UCC2818APWG4 ACTIVE TSSOP PW 16 90 Green (RoHS & no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR UCC2818APWR ACTIVE TSSOP PW 16 2000 Green (RoHS & no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR UCC2818APWRG4 ACTIVE TSSOP PW 16 2000 Green (RoHS & no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR UCC3817AD ACTIVE SOIC D 16 40 Green (RoHS & no Sb/Br) CU NIPDAU Level-1-260C-UNLIM UCC3817ADG4 ACTIVE SOIC D 16 40 Green (RoHS & no Sb/Br) CU NIPDAU Level-1-260C-UNLIM UCC3817ADR ACTIVE SOIC D 16 2500 Green (RoHS & no Sb/Br) CU NIPDAU Level-1-260C-UNLIM UCC3817ADRG4 ACTIVE SOIC D 16 2500 Green (RoHS & no Sb/Br) CU NIPDAU Level-1-260C-UNLIM UCC3817AN ACTIVE PDIP N 16 25 Green (RoHS & no Sb/Br) CU NIPDAU N / A for Pkg Type UCC3817ANG4 ACTIVE PDIP N 16 25 Green (RoHS & no Sb/Br) CU NIPDAU N / A for Pkg Type UCC3818AD ACTIVE SOIC D 16 40 Green (RoHS & no Sb/Br) CU NIPDAU Level-1-260C-UNLIM UCC3818ADG4 ACTIVE SOIC D 16 40 Green (RoHS & no Sb/Br) CU NIPDAU Level-1-260C-UNLIM UCC3818ADR ACTIVE SOIC D 16 2500 Green (RoHS & no Sb/Br) CU NIPDAU Level-1-260C-UNLIM UCC3818ADRG4 ACTIVE SOIC D 16 2500 Green (RoHS & no Sb/Br) CU NIPDAU Level-1-260C-UNLIM UCC3818AN ACTIVE PDIP N 16 25 Green (RoHS & no Sb/Br) CU NIPDAU N / A for Pkg Type UCC3818ANG4 ACTIVE PDIP N 16 25 Green (RoHS & no Sb/Br) CU NIPDAU N / A for Pkg Type UCC3818APW ACTIVE TSSOP PW 16 90 Green (RoHS & no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR UCC3818APWG4 ACTIVE TSSOP PW 16 90 Green (RoHS & no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR Addendum-Page 2 Samples (Requires Login) PACKAGE OPTION ADDENDUM www.ti.com Orderable Device 30-Jul-2011 Status (1) Package Type Package Drawing Pins Package Qty Eco Plan (2) Lead/ Ball Finish MSL Peak Temp (3) UCC3818APWR ACTIVE TSSOP PW 16 2000 Green (RoHS & no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR UCC3818APWRG4 ACTIVE TSSOP PW 16 2000 Green (RoHS & no Sb/Br) CU NIPDAU Level-2-260C-1 YEAR Samples (Requires Login) (1) The marketing status values are defined as follows: ACTIVE: Product device recommended for new designs. LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect. NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design. PREVIEW: Device has been announced but is not in production. Samples may or may not be available. OBSOLETE: TI has discontinued the production of the device. (2) Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check http://www.ti.com/productcontent for the latest availability information and additional product content details. TBD: The Pb-Free/Green conversion plan has not been defined. Pb-Free (RoHS): TI's terms "Lead-Free" or "Pb-Free" mean semiconductor products that are compatible with the current RoHS requirements for all 6 substances, including the requirement that lead not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, TI Pb-Free products are suitable for use in specified lead-free processes. Pb-Free (RoHS Exempt): This component has a RoHS exemption for either 1) lead-based flip-chip solder bumps used between the die and package, or 2) lead-based die adhesive used between the die and leadframe. The component is otherwise considered Pb-Free (RoHS compatible) as defined above. Green (RoHS & no Sb/Br): TI defines "Green" to mean Pb-Free (RoHS compatible), and free of Bromine (Br) and Antimony (Sb) based flame retardants (Br or Sb do not exceed 0.1% by weight in homogeneous material) (3) MSL, Peak Temp. -- The Moisture Sensitivity Level rating according to the JEDEC industry standard classifications, and peak solder temperature. Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided. 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OTHER QUALIFIED VERSIONS OF UCC2818A : * Automotive: UCC2818A-Q1 NOTE: Qualified Version Definitions: * Automotive - Q100 devices qualified for high-reliability automotive applications targeting zero defects Addendum-Page 3 PACKAGE MATERIALS INFORMATION www.ti.com 14-Jul-2012 TAPE AND REEL INFORMATION *All dimensions are nominal Device Package Package Pins Type Drawing SPQ Reel Reel A0 Diameter Width (mm) (mm) W1 (mm) B0 (mm) K0 (mm) P1 (mm) W Pin1 (mm) Quadrant 10.3 2.1 8.0 16.0 Q1 UCC2817ADR SOIC D 16 2500 330.0 16.4 6.5 UCC2817APWR TSSOP PW 16 2000 330.0 12.4 6.9 5.6 1.6 8.0 12.0 Q1 UCC2818ADR SOIC D 16 2500 330.0 16.4 6.5 10.3 2.1 8.0 16.0 Q1 UCC2818APWR TSSOP PW 16 2000 330.0 12.4 6.9 5.6 1.6 8.0 12.0 Q1 UCC3817ADR SOIC D 16 2500 330.0 16.4 6.5 10.3 2.1 8.0 16.0 Q1 UCC3818ADR SOIC D 16 2500 330.0 16.4 6.5 10.3 2.1 8.0 16.0 Q1 UCC3818APWR TSSOP PW 16 2000 330.0 12.4 6.9 5.6 1.6 8.0 12.0 Q1 Pack Materials-Page 1 PACKAGE MATERIALS INFORMATION www.ti.com 14-Jul-2012 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) UCC2817ADR SOIC D 16 2500 333.2 345.9 28.6 UCC2817APWR TSSOP PW 16 2000 367.0 367.0 35.0 UCC2818ADR SOIC D 16 2500 333.2 345.9 28.6 UCC2818APWR TSSOP PW 16 2000 367.0 367.0 35.0 UCC3817ADR SOIC D 16 2500 333.2 345.9 28.6 UCC3818ADR SOIC D 16 2500 333.2 345.9 28.6 UCC3818APWR TSSOP PW 16 2000 367.0 367.0 35.0 Pack Materials-Page 2 IMPORTANT NOTICE Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, enhancements, improvements and other changes to its semiconductor products and services per JESD46, latest issue, and to discontinue any product or service per JESD48, latest issue. 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