GM3842A, GM3843A GM3844A, GM3845A CURRENT MODE PWM CONTROLLER Description Features GM384XA series is high performance with fixedfrequency current mode PWM controllers. They are specially designed for off-Line and DC-to-DC converter applications with minimum external components. These devices feature a trimmed oscillator for precise duty cycle control, a temperature compensated reference, high gain error amplifier, current sensing comparator, and high current totem pole output which is suitable for driving MOSFETs. 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 The under voltage lock-out (U.V.L.O.) is designed to operated with 0.17mA typ. start-up current, allowing an efficient bootstrap supply voltage design. The U.V.L.O. thresholds for the AMC3842A/44A are 16V (on) and 10V (off) which are ideal for off-line applications. The corresponding typical threshold for the GM3843A/45A is 8.4V (on) and 7.6V (off). The GM3842A/43A can operated within 100% duty cycle and the GM3844A/45A can operated within 50% duty cycle. Under Voltage Lockout with Hysteresis High Current totem Pole Output Stage Available Options Application Hysteresis Max. Duty Cycle Off-line flyback or forward converters GM3842A 16V 6V < 100% Monitor Power Supply GM3843A 8.4V 0.8V < 100% GM3844A 16V 6V < 50% GM3845A 8.4V 0.8V < 50% DC-to DC buck boost converter GM384x V1.00 Start-UP Voltage Device www.gammamicro.com.tw 1 GM3842A, GM3843A GM3844A, GM3845A CURRENT MODE PWM CONTROLLER Marking Information and Pin Configurations (Top View) SO8 7. DIP8 6. Output VCC - GM384X AYWW 1. COMP 2. FB 6. Output 5. GND 7. VCC 8. VREF 5. GND 8. VREF GM384X AYWW 4. RT / CT 3. ISENSE 4. RT / CT 3. ISENSE 1. Output A 2. Input A - A: Assembly / Test site code Y: Year WW: Week Ordering Information GM384x V1.00 Ordering Number 2 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 GM3842A, GM3843A GM3844A, GM3845A CURRENT MODE PWM CONTROLLER Absolute Maximum Ratings PARAMETER Symbol RATINGS UNITS VCC 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 ISINK(E.A.) 10 mA TA - 40 to 125- ℃ - 65 to 150 ℃ 260 ℃ Supply Voltage (low impedance source) Error Amp Output Sink Current Operating Ambient Temperature Range Storage Temperature Lead Temperature (soldering 10 sec.) * Maximum Package Power Dissipation Limits must be observed. Block Diagram 7 Internal Bias U.V.L.O. 5V VREF VREF 8 VCC 36V EN 5 GND VREF Good Logic Error Amp R 1V PWM Latch R 1 COMP 6 OUTPUT S 4 3 T Oscillator 5 GND GM384x V1.00 CURRENT SENSE RT/CT 2R 2 VFB 7 V CC Current Sense 3 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 4.9 5.0 5.1 V Reference Section Reference output Voltage VREF TJ= 25°C, IREF= 1mA Line Regulation ∆VREF-V 12V < VCC < 25V 6.0 20 mV Load Regulation ∆VREF-I 1mA < IREF < 20mA 6.0 25 mV -100 -180 mA 52 57 KHz 0.05 1 % Short CirCuit output Current ISC TA=25°C f TJ= 25°C Oscillator Section Oscillation Frequency Frequency Change with Voltage Oscillator Amplitude 47 ∆f/∆VCC 12V < VCC < 25V V(osc) (Peak to Peak) 1.6 V VFB = 3V -0.1 -2 µA 2.58 V Error Amplifier Section Input Bias Current IBIAS Input Voltage Open Loop Voltage Gain Power Supply Rejection Ratio VI(EA) VPIN1 = 2.5V 2.42 2.5 AVOL(EA) 2V < VO < 4V 65 90 dB 60 70 dB 2 7 mA PSRR(EA) 12V < VCC < 25V Output Sink Current ISINK(EA) VPIN2 = 2.7V, VPIN1 = 1.1V Output Source Current Isource(EA) VPIN2 = 2.3V, VPIN1 = 5V -0.5 -1.0 mA 5.0 6.0 V High Output Voltage VOH(EA) VPIN2 = 2.3V, RL =15K to GND Low Output Voltage VOL(A) VPIN2 = 2.7V, RL =15K to GND 0.8 1.1 V 3.0 3.15 V/V VPIN1 = 5V (Note 1) 1.0 1.1 V 70 Current Sense Section Current Sense Input Voltage Gain Maximum Input Signal GV VI(MAX) (Note 1 and 2) 2.85 Supply Voltage Rejection SVR 12V < VCC < 25V (Note 1) Input Bias Current IBIAS VPIN3 = 3V -3.0 -10 ISINK = 20mA 0.8 0.4 ISINK = 200mA 1.4 2.2 dB µA GM384x V1.00 Output Section 4 Low Output Voltage High Output Voltage VOL VOH V ISource= -20mA 13 13.5 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 Electrical Characteristics (TA = 0°C to 70°C, VCC=15V, CT=3.3nF, RT=10k , unless otherwise specified) Parameter Symbol Condition Min Typ Max GM3842A, GM3844A 14.5 16.0 17.5 GM3843A, GM3845A 7.8 8.4 9.0 GM3842A, GM3844A 8.5 10 11.5 GM3843A, GM3845A 7.0 7.6 8.2 GM3842A, GM3844A 95 97 100 GM3843A, GM3845A 47 45 50 Unit Undervoltage Lockout Section Start Threshold Minimum Operating Voltage (after turn on) VTH(ST) V V VOPR(MIN) PWM Section Maximum Duty Cycle Minimum Duty Cycle D(MAX) % D(MIN) 0 % 0.17 0.3 mA 13 17 mA Total Standby Current Start-Up Current IST Operating Supply Current ICC(OPR) Zero Voltage VZ VPIN3 = VPIN2 = 0V ICC = 25mA 30 35 V GM384x V1.00 * 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 5 GM3842A, GM3843A GM3844A, GM3845A CURRENT MODE PWM CONTROLLER Typical Performance Characteristics % RT (K) VCC = 15V CT = 1000pF 50 CT = 200pF CT = 500pF CT = 1nF 20 50 30 CT = 5nF 20 10 CT = 10pF 10 CT = 2nF CT = 2nF 5 CT = 1000pF 2 VCC = 15V 1 TA = 25°C 20 2 50 100 200 300 500 fosc (KHZ) Figure 1. Timing Resistor vs. Oscillator Frequency Dmax (%) 1 10 20 30 50 100 (dB) 80 80 60 70 40 60 20 50 0 RT (k Figure 3. Maximum Output Duty Cycle vs. Timing Resistor (GM3842A/43A) 1 2 3 5 200 300 500 -20 l0 VCC = 15V VO = 2V to 4V RL = 100K TA = 25°C l00 lk l0k l00k lM Figure 4. Error Amp Open-Loop Gain vs. Frequency ISC (mA) VTH (V) VCC = 15V 1.0 0.8 l00 TA = 125°C 90 VCC = 15V TA = 25°C 0.6 80 0.4 70 0.2 60 50 0 2 6 4 VO (V) 6 Vsat (V) -1 0 25 50 75 l00 T (°C) A Figure 6. Reference Short Circuit Current vs. Temperature ICC (mA) Source Saturation (Load to Ground) ISENSE = 0V VFB = 0V RT = 10K TA = 25°C CT = 3.3nF VCC = 15V -2 20 50μs Pulsed Load 120Hz Rate 3 2 l 10 Sink Saturation (Load to V+) 5 0 0 0 200 400 600 Io (mA) Figure 7. Output Saturation Voltage vs. Load Current TA= 25°C GM3842A / 44A l5 GM3843A / 45A GM384x V1.00 Figure 5. Current Sense Input Threshold vs. Error Amp Output Voltage fosc (kHz) Figure 2. Output Dead-Time vs. Oscillator Frequency VCC = 15V 90 CT = 3.3nF TA = 25°C 40 CT = 200pF 5 CT = 10pF 10 CT = 500pF CT = 1nF CT = 5nF 0 10 20 30 VCC (V) Figure 8. Supply Current vs. Supply Voltage GM3842A, GM3843A GM3844A, GM3845A CURRENT MODE PWM CONTROLLER Package Outline Dimensions – SO 8 0.189 - 0.197 (4.800 - 5.004) 0.228 - 0.244 (5.791 - 6.198) 0.016 - 0.050 (0.406 - 0.270) D 0.014 - 0.020 (0.356 - 0.508) 0.050 (1.270) TYP 0.150 - 0.157 (3.810 - 3.988) 0.053 - 0.059 (1.346 - 1.753) SEATING PLAN 0.004 - 0.010 (0.012 - 0.254) 8.0 MAX 0.008 - 0.010 (0.203 - 0.254) Package Outline Dimensions – DIP 8 0.250 +/- 0.005 (6.350 +/- 0.127) 0.370 - 0.400 (9.474 - 10.150) 0.300 - 0.320 (7.620 - 8.128) 0.06 (1.524) 0.125 - 0.140 (3.175 - 3.556) 0.045 +/- 0.015 (1.143 +/- 0.183) 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 GM384x V1.00 0.145 - 0.200 (3.683 - 5.080) 7 GM3842A, GM3843A GM3844A, GM3845A CURRENT MODE PWM CONTROLLER Ordering Number GM 3842 A APM Gamma Micro Circuit Type Revision S8 R Package Type Shipping Type R: Taping & Reel T: Tube GM384x V1.00 S8: SO 8 D8: DIP 8 8 1