GM3842A_1 GAMMA | Alldatasheet

Document overview

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Technical content

Features

‹ Low Start-Up and Operating Current ‹ Automatic Feed Forward Compensation ‹ Current Mode Operating Frequency up to 500KHz ‹ Trimmed Oscillator Discharge Current for Precise Duty Cycle Control ‹ Latching PWM for Cycle-By-Cycle Current Limiting ‹ Under Voltage Lockout with Hysteresis ‹ High Current totem Pole Output Stage Available Options Application Device Start-UP Voltage Hysteresis Max. Duty Cycle GM3842A 16V 6V < 100% GM3843A 8.4V 0.8V < 100% GM3844A 16V 6V < 50% GM3845A 8.4V 0.8V < 50% Off-line flyback or forward converters DC-to DC buck boost converter Monitor Power Supply

2 GM384x V1.00 GM3842A, GM3843A GM3844A, GM3845A CURRENT MODE PWM CONTROLLER Marking Information and Pin Configurations (Top View) SO8 DIP8 A: Assembly / Test site code Y: Year WW: Week

Ordering Information

Ordering Number Package Shipping GM3842AD8T DIP-8 60 Units / Tube GM3842AS8T SOP-8 100 Units / Tube GM3842AS8R SOP-8 2,500 Units / Tape & Reel GM3843AD8T DIP-8 60 Units / Tube GM3843AS8T SOP-8 100 Units / Tube GM3843AS8R SOP-8 2,500 Units / Tape & Reel GM3844AD8T DIP-8 60 Units / Tube GM3844AS8T SOP-8 100 Units / Tube GM3844AS8R SOP-8 2,500 Units / Tape & Reel GM3845AD8T DIP-8 60 Units / Tube GM3845AS8T SOP-8 100 Units / Tube GM3845AS8R SOP-8 2,500 Units / Tape & Reel 7. V CC 8. VREF 2. FB 1. COMP 6. Output - 5. GND 4. R T / CT 3. I SENSE GM384X AYWW GM384X AYWW 7. VCC 8. VREF 2. Input A - 1. Output A 6. Output 5. GND 4. R T / CT 3. I SENSE

GM3842A, GM3843A GM3844A, GM3845A CURRENT MODE PWM CONTROLLER GM384x V1.00 Absolute Maximum Ratings PARAMETER Symbol RATINGS UNITS Supply Voltage (low impedance source) V CC 30 V Output Current, Source or Sink * IO ±1 A Input Voltage (analog inputs pins 2, and 3) VI - 0.3 to + 5.5 V Maximum Power Dissipation (TA= 25°C) PD 1.0 W Error Amp Output Sink Current ISINK(E.A.) 10 mA Operating Ambient Temperature Range T A - 40 to 125- ℃ Storage Temperature - 65 to 150 ℃ Lead Temperature (soldering 10 sec.) 260 ℃ * Maximum Package Power Dissipation Limits must be observed. Block Diagram VREF Internal Bias 36V EN 5V VREF U.V.L.O. VREF Good Logic Error Amp Current Sense Oscillator R 1V R S PWM Latch VFB CURRENT SENSE RT/CT GND OUTPUT VCC GND VCC COMP T

4 GM384x V1.00 GM3842A, GM3843A GM3844A, GM3845A CURRENT MODE PWM CONTROLLER Electrical Characteristics (TA = 0°C to 70°C, *VCC=15V, CT=3.3nF, RT=10k , unless otherwise specified) Parameter Symbol Condition Min Typ Max Unit Reference Section Reference output Voltage VREF TJ= 25°C, IREF= 1mA 4.9 5.0 5.1 V Line Regulation ∆VREF-V 12V < VCC < 25V 6.0 20 mV Load Regulation ∆VREF-I 1mA < IREF < 20mA 6.0 25 mV Short CirCuit output Current ISC TA=25°C -100 -180 mA Oscillator Section Oscillation Frequency f TJ= 25°C 47 52 57 KHz Frequency Change with Voltage ∆f/∆VCC 12V < VCC < 25V 0.05 1 % Oscillator Amplitude V(osc) (Peak to Peak) 1.6 V Error Amplifier Section Input Bias Current I BIAS V FB = 3V -0.1 -2 µA Input Voltage V I(EA) VPIN1 = 2.5V 2.42 2.5 2.58 V Open Loop Voltage Gain AVOL(EA) 2V < VO < 4V 65 90 dB Power Supply Rejection Ratio PSRR(EA) 12V < VCC < 25V 60 70 dB Output Sink Current ISINK(EA) VPIN2 = 2.7V, VPIN1 = 1.1V 2 7 mA Output Source Current Isource(EA) VPIN2 = 2.3V, VPIN1 = 5V -0.5 -1.0 mA High Output Voltage V OH(EA) VPIN2 = 2.3V, RL =15K to GND 5.0 6.0 V Low Output Voltage V OL(A) VPIN2 = 2.7V, RL =15K to GND 0.8 1.1 V Current Sense Section Current Sense Input Voltage Gain GV (Note 1 and 2) 2.85 3.0 3.15 V/V Maximum Input Signal VI(MAX) VPIN1 = 5V (Note 1) 1.0 1.1 V Supply Voltage Rejection SVR 12V < VCC < 25V (Note 1) 70 dB Input Bias Current IBIAS VPIN3 = 3V -3.0 -10 µA Output Section ISINK = 20mA 0.8 0.4 Low Output Voltage VOL ISINK = 200mA 1.4 2.2 V ISource= -20mA 13 13.5 High Output Voltage VOH Isource = -200mA 12 13 V Rise Time tr TJ = 25°C, CL = 1nF (Note 3) 45 150 ns Fall Time tf TJ = 25°C, CL = 1nF (Note 3) 35 150 ns

GM3842A, GM3843A GM3844A, GM3845A CURRENT MODE PWM CONTROLLER GM384x V1.00 Electrical Characteristics (TA = 0°C to 70°C, VCC=15V, CT=3.3nF, RT=10k , unless otherwise specified) Parameter Symbol Condition Min Typ Max Unit Undervoltage Lockout Section GM3842A, GM3844A 14.5 16.0 17.5 Start Threshold VTH(ST) GM3843A, GM3845A 7.8 8.4 9.0 V GM3842A, GM3844A 8.5 10 11.5Minimum Operating Voltage (after turn on) VOPR(MIN) GM3843A, GM3845A 7.0 7.6 8.2 V PWM Section GM3842A, GM3844A 95 97 100 Maximum Duty Cycle D(MAX) GM3843A, GM3845A 47 45 50 Minimum Duty Cycle D (MIN) 0 % Total Standby Current Start-Up Current I ST 0.17 0.3 mA Operating Supply Current ICC(OPR) V PIN3 = VPIN2 = 0V 13 17 mA Zero Voltage V Z I CC = 25mA 30 35 V * Adjust VCC above the Startup threshold before setting to l5 V. Note 1: Parameter measured at trip point of latch with VPIN2 = 0V Note 2: Gain defined as A = VPIN1 / VPIN3; 0V < VPIN3 < 0.5V Note 3: These parameters, although quaranteed, are not 1005 tested in production

GM3842A, GM3843A GM3844A, GM3845A CURRENT MODE PWM CONTROLLER GM384x V1.00 Package Outline Dimensions – SO 8 (0.356 - 0.508) (0.406 - 0.270) 0.016 - 0.050 D 0.189 - 0.197 (4.800 - 5.004) SEATING PLAN 0.014 - 0.020 0.150 - 0.157 (3.810 - 3.988) 0.008 - 0.010 (0.203 - 0.254) 8.0 MAX 0.053 - 0.059 (1.346 - 1.753) 0.004 - 0.010 0.228 - 0.244 (5.791 - 6.198) 0.050 (1.270) TYP (0.012 - 0.254) Package Outline Dimensions – DIP 8 0.300 - 0.320 (7.620 - 8.128) 0.045 +/- 0.015 (1.143 +/- 0.183) 0.250 +/- 0.005 (6.350 +/- 0.127) 0.370 - 0.400 (9.474 - 10.150) 0.06 (1.524) 0.145 - 0.200 (3.683 - 5.080) 0.125 - 0.140 (3.175 - 3.556) 0.108 +/- 0.003 (0.457 +/- 0.076) 0.100 +/- 0.010 (2.540 +/- 0.254) J 0.009 - 0.010 (0.299 - 0.381) 95 +/- 5

8 GM384x V1.00 GM3842A, GM3843A GM3844A, GM3845A CURRENT MODE PWM CONTROLLER Ordering Number GM 3842 A S8 R APM Gamma Micro Circuit Type Revision Package Type S8: SO 8 D8: DIP 8 Shipping Type R: Taping & Reel T: Tube