UC2842AQ, UC2843AQ, UC2844AQ, UC2845AQ CURRENT-MODE PWM CONTROLLER SGLS164 – APRIL 2003 D Extended Temperature Performance of D 8-PIN PACKAGE (TOP VIEW) –40°C to 125°C D Optimized for Off-line and DC to DC D D D D D D D D D D D Converters Low Start Up Current (<0.5 mA) Trimmed Oscillator Discharge Current Automatic Feed Forward Compensation Pulse-by-Pulse Current Limiting Enhanced Load Response Characteristics Under-Voltage Lockout With Hysteresis Double Pulse Suppression High Current Totem Pole Output Internally Trimmed Bandgap Reference 500 kHz Operation Low RO Error Amp COMP VFB 1 8 2 7 ISENSE RT/CT 3 6 4 5 VREF VCC OUTPUT GND D 14-PIN PACKAGE (TOP VIEW) COMP NC VFB NC 1 14 2 13 3 12 4 11 ISENSE NC RT/CT 5 10 6 9 7 8 VREF NC VCC VC OUTPUT GND PWR GND description The UC2842A/3A/4A/5A family of control ICs is a pin for pin compatible improved version of the UC2842/3/4/5 family. Providing the necessary features to control current mode switched mode power supplies, this family has the following improved features. Start up current is guaranteed to be less than 0.5 mA. Oscillator discharge is trimmed to 8.3 mA. During under voltage lockout, the output stage can sink at least 10 mA at less than 1.2 V for VCC over 5 V. The difference between members of this family are shown in the table below. PART NUMBER UVLO ON UVLO OFF MAXIMUM DUTY CYCLE UC2842A 16 V 10 V <100% UC2843A 8.5 V 7.9 V <100% UC2844A 16 V 10 V <50% UC2845A 8.5 V 7.9 V <50% 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. Copyright 2003, Texas Instruments Incorporated PRODUCTION DATA information is current as of publication date. Products conform to specifications per the terms of Texas Instruments standard warranty. Production processing does not necessarily include testing of all parameters. POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 1 UC2842AQ, UC2843AQ, UC2844AQ, UC2845AQ CURRENT-MODE PWM CONTROLLER SGLS164 – APRIL 2003 ORDERING INFORMATION† TA 40°C to 125°C –40°C ORDERABLE PART NUMBER PACKAGE‡ TOP-SIDE MARKING SOIC-8 – D8 Tape and reel UC2842AQD8R 2842AQ SOIC-8 – D8 Tube UC2842AQD8 2842AQ SOIC-14 – D Tape and reel UC2842AQDR 2842AQ SOIC-14 – D Tube UC2842AQD 2842AQ SOIC-8 – D8 Tape and reel UC2843AQD8R 2843AQ SOIC-8 – D8 Tube UC2843AQD8 2843AQ SOIC-14 – D Tape and reel UC2843AQDR 2843AQ SOIC-14 – D Tube UC2843AQD 2843AQ SOIC-8 – D8 Tape and reel UC2844AQD8R 2844AQ SOIC-8 – D8 Tube UC2844AQD8 2844AQ SOIC-14 – D Tape and reel UC2844AQDR 2844AQ SOIC-14 – D Tube UC2844AQD 2844AQ SOIC-8 – D8 Tape and reel UC2845AQD8R 2845AQ SOIC-8 – D8 Tube UC2845AQD8 2845AQ SOIC-14 – D Tape and reel UC2845AQDR 2845AQ SOIC-14 – D Tube UC2845AQD 2845AQ † Package drawings, standard packing quantities, thermal data, symbolization, and PCB design guidelines are available at www.ti.com/sc/package. block diagram NOTES: 1. A = DIL-8 Pin Number. B = SO-14 Pin Number. 2. Toggle flip flop used only in 2844A and 2845A. 2 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 UC2842AQ, UC2843AQ, UC2844AQ, UC2845AQ CURRENT-MODE PWM CONTROLLER SGLS164 – APRIL 2003 Ordering Information UC 284 4 A Q D R TAPE and REEL INDICATOR PACKAGE D = Plastic SOIC, 14 pin D8 = Plastic SOIC, 8 pin AUTOMOTIVE TEMPERATURE RANGE INDICATOR IMPROVED PERFORMANCE INDICATOR PRODUCT OPTION 2 through 5 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 3 UC2842AQ, UC2843AQ, UC2844AQ, UC2845AQ CURRENT-MODE PWM CONTROLLER SGLS164 – APRIL 2003 absolute maximum ratings over operating free-air temperature range (unless otherwise noted)†‡ VCC voltage (low impedance source) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 V VCC voltage (ICC mA) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . self limiting Output current, IO . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ±1 A Output energy (capacitive load) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5 µJ Analog Inputs (pins 3, 5) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –0.3 V to 6.3 V Error Amp Output Sink current . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 mA Power Dissipation at TA < +25_C (D package) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 W Package thermal impedance, θJA (see Note 1): D (8-pin) package . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97°C/W Storage temperature range, Tstg . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . –65_C to 150_C Lead temperature soldering 1,6 mm (1/16 inch) from case for 10 seconds . . . . . . . . . . . . . . . . . . . . . . . 260_C † 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. ‡ Unless otherwise indicated, voltages are reference to ground and currents are positive into and negative out of the specified terminals. NOTE 1: Long term high–temperature storage and/or extended use at maximum recommended operating conditions may result in a reduction of overall device life. See http://www.ti.com/ep_quality for additional information on enhanced plastic packaging. electrical characteristics, TA = –40_C to 125_C, VCC = 15 V (see Note 1), RT = 10 kΩ, CT = 3.3 nF, and TA = TJ (unless otherwise stated) PARAMETER TEST CONDITIONS MIN TYP MAX UNITS Reference Section Output voltage TJ = 25_C, Line regulation voltage Load regulation voltage Temperature stability See Notes 2 and 3 Total output variation voltage Line, Load, Temp. Output noise voltage f = 10 Hz to 10 kHz, See Note 2 Long term stability 1000 hours, 4.95 5.0 5.05 VIN = 12 V to 25 V 6 20 mV IO = 1 mA to 20 mA 6 25 mV 0.2 0.4 mV/_C 5.1 V IO = 1 mA 4.9 See Note 2 5 25 mV –30 –100 –180 mA 47 52 57 kHz 0.2 1 % TA = 125_C Output short-circuit current µV 50 TJ = 25_C V Oscillator Section Initial accuracy See Note 4 Voltage stability VCC = 12 V to 25 V Temperature stability TA = MIN to MAX, See Note 2 5 % Amplitude peak-to-peak V pin 7, See Note 2 1.7 V Discharge current V pin 7 = 2 V, V See Note 5 4 POST OFFICE BOX 655303 TJ = 25_C TJ = 25_C 7.8 TJ = Full range 7.5 • DALLAS, TEXAS 75265 8.3 8.8 8.8 mA UC2842AQ, UC2843AQ, UC2844AQ, UC2845AQ CURRENT-MODE PWM CONTROLLER SGLS164 – APRIL 2003 electrical characteristics, TA = –40_C to 125_C, VCC = 15 V (see Note 1), RT = 10 kΩ, CT = 3.3 nF, and TA = TJ (unless otherwise stated) PARAMETER TEST CONDITIONS MIN TYP MAX UNITS Error Amplifier Section Input voltage COMP = 2.5 V 2.45 Input bias current Open loop voltage gain (AVOL) VO = 2 V to 4 V Unity gain bandwidth See Note 2 PSRR VCC = 12 V to 25 V Output sink current FB = 2.7 V, COMP = 1.1 V Output source current FB = 2.3 V, COMP = 5 V VOUT high FB = 2.3 V, RL = 15 kΩ to GND VOUT low FB = 2.7 V, RL = 15 kΩ to VREF TJ = 25_C 2.5 2.55 V –0.3 –1 µA 65 90 dB 0.7 1 MHz 60 70 dB 2 6 mA –0.5 –0.8 mA 5 6 V 0.7 1.1 V 2.85 3 3.15 V/V 0.9 1 1.1 V Current Sense Section Gain See Notes 6 and 7 Maximum input signal COMP = 5 V, PSRR VCC = 12 V to 25 V,See Note 6 See Note 6 70 –2 –10 µA 150 300 ns IOUT = 20 mA 0.1 0.4 IOUT = 200 mA 15 2.2 Input bias current Delay to output dB ISENSE = 0 V to 2 V, See Note 2 Output Section (OUT) Low level output voltage Low-level High level output voltage High-level IOUT = –20 mA 13 13.5 IOUT = –200 mA 12 13.5 V V Rise time CL = 1 nF, See Note 2 TJ = 25_C 50 150 ns Fall time CL = 1 nF, See Note 2 TJ = 25_C 50 150 ns UVLO saturation VCC = 5 V, IOUT = 10 mA 0.7 1.2 V Undervoltage Lockout Section Start threshold Minimum operation voltage after turn on POST OFFICE BOX 655303 UC2842A, UC2844A 15 16 17 UC2843A, UC2845A 7.8 8.4 9 UC2842A, UC2844A 9 10 11 UC2843A, UC2845A 7 7.6 8.2 • DALLAS, TEXAS 75265 V V 5 UC2842AQ, UC2843AQ, UC2844AQ, UC2845AQ CURRENT-MODE PWM CONTROLLER SGLS164 – APRIL 2003 electrical characteristics, TA = –40_C to 125_C, VCC = 15 V (see Note 1), RT = 10 kΩ, CT = 3.3 nF, and TA = TJ (unless otherwise stated) PARAMETER TEST CONDITIONS MIN TYP MAX UNITS PWM Section Maximum duty cycle UC2842A, UC2843A 94 96 100 UC2844A, UC2845A 47 48 50 Minimum duty cycle 0 % % Total Standby Current Start-up current Operating supply current FB = 0 V, SENSE = 0 V 0.3 0.5 mA 11 17 mA VCC internal zener voltage ICC = 25 mA 30 34 V NOTES: 1. Adjust VCC above the start threshold before setting at 15 V. 2. Not production tested. 3. Temperature stability, sometimes referred to as average temperature coefficient, is described by the equation: V (max) – VREF (min). VREF (max) and VREF (min) are the maximum and minimum reference voltage measured Temp Stability = REF TJ (max) – TJ (min) over the appropriate temperature range. Note that the extremes in voltage do not necessarily occur at the extremes in temperature. 4. Output frequency equals oscillator frequency for the UC2842A and UC2843A. Output frequency is one half oscillator frequency for the UC2844A and UC2845A. 5. This parameter is measured with RT = 10 kΩ to VREF. This contributes approximately 300 µA of current to the measurement. The total current flowing into the RT/C pin will be approximately 300 µA higher than the measured value. 6. Parameter measured at trip point of latch with VFB at 0 V. 7. Gain is defined by: DVCOMP ; 0 v VSENSE v 0.8 V. A= DVSENSE PA RAMETER MEASUREMENT INFORMATION Error Amp can source and sink up to 0.5 mA, and sink up to 2 mA. Figure 1. Error Amp Configuration 6 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 UC2842AQ, UC2843AQ, UC2844AQ, UC2845AQ CURRENT-MODE PWM CONTROLLER SGLS164 – APRIL 2003 PARAMETER MEASUREMENT INFORMATION During UVLO, the Output is low. Figure 2. Under Voltage Lockout Peak Current (Is) is Determined By The Formula: IsmaxȀ 1.0V RS A small RC filter may be required to supress switch transients. Figure 3. Current Sense Circuit POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 7 UC2842AQ, UC2843AQ, UC2844AQ, UC2845AQ CURRENT-MODE PWM CONTROLLER SGLS164 – APRIL 2003 PARAMETER MEASUREMENT INFORMATION Error Amplifier Open-Loop Frequency Response Output Saturation Characteristics Figure 5 Figure 4 AP PLICATION INFORMATION Oscillator Frequency vs Timing Resistance Figure 6. Oscillator 8 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 Maximum Duty Cycle vs Timing Resistor UC2842AQ, UC2843AQ, UC2844AQ, UC2845AQ CURRENT-MODE PWM CONTROLLER SGLS164 – APRIL 2003 APPLICATION INFORMATION High peak currents associated with capacitive loads necessitate careful grounding techniques. Timing and bypass capacitors should be connected close to pin 5 in a single point ground. The transistor and 5k potentiometer are used to sample the oscillator waveform and apply an adjustable ramp to pin 3. Figure 7. Open-Loop Laboratory Text Fixture A fraction of the oscillator ramp can be resistively summed with the current sense signal to provide slope compensation for converters requiring duty cycles over 50%. Note that capacitor, C, forms a filter with R2 to suppress the leading edge switch spikes. Figure 8. Slope Complression POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 9 UC2842AQ, UC2843AQ, UC2844AQ, UC2845AQ CURRENT-MODE PWM CONTROLLER SGLS164 – APRIL 2003 APPLICATION INFORMATION Power Supply Specifications 1. 2. 3. 4. 5. Input Voltage 95VAC to 130VAC (50Hz/60Hz) Line Isolation 3750V Switching Frequency 40 kHz Efficiency, Full Load 70% Output Voltage: A. +5V, ±5%; 1A to 4A Load B. +12V, ±3%; 0.1A to 0.3A Load Ripple voltage: 100 mV P-P Max C. –12V, ±3%; 0.1A to 0.3A Load Ripple voltage: 100 mV P-P Max Figure 9. Off-Line Flyback Regulator 10 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 MECHANICAL DATA MSOI002B – JANUARY 1995 – REVISED SEPTEMBER 2001 D (R-PDSO-G**) PLASTIC SMALL-OUTLINE PACKAGE 8 PINS SHOWN 0.020 (0,51) 0.014 (0,35) 0.050 (1,27) 8 0.010 (0,25) 5 0.008 (0,20) NOM 0.244 (6,20) 0.228 (5,80) 0.157 (4,00) 0.150 (3,81) Gage Plane 1 4 0.010 (0,25) 0°– 8° A 0.044 (1,12) 0.016 (0,40) Seating Plane 0.010 (0,25) 0.004 (0,10) 0.069 (1,75) MAX PINS ** 0.004 (0,10) 8 14 16 A MAX 0.197 (5,00) 0.344 (8,75) 0.394 (10,00) A MIN 0.189 (4,80) 0.337 (8,55) 0.386 (9,80) DIM 4040047/E 09/01 NOTES: A. B. C. D. All linear dimensions are in inches (millimeters). This drawing is subject to change without notice. Body dimensions do not include mold flash or protrusion, not to exceed 0.006 (0,15). Falls within JEDEC MS-012 POST OFFICE BOX 655303 • DALLAS, TEXAS 75265 1 IMPORTANT NOTICE Texas Instruments Incorporated and its subsidiaries (TI) reserve the right to make corrections, modifications, enhancements, improvements, and other changes to its products and services at any time and to discontinue any product or service without notice. Customers should obtain the latest relevant information before placing orders and should verify that such information is current and complete. All products are sold subject to TI’s terms and conditions of sale supplied at the time of order acknowledgment. TI warrants performance of its hardware products to the specifications applicable at the time of sale in accordance with TI’s standard warranty. Testing and other quality control techniques are used to the extent TI deems necessary to support this warranty. Except where mandated by government requirements, testing of all parameters of each product is not necessarily performed. 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