GP3842

ISSUED DATE :2003/05/20 REVISED DATE :2004/09/30B GP3842 Description HIGH PERFORMANCE CURRENT MODE CONTROLERS The GP3842 is high performance fixed frequency current mode controllers. This is specifically designed for Off-Line and DC TO DC converter applications offering the designer a cost-effective solution with minimal external components. These integrated circuits feature a trimmed oscillator for precise duty cycle control. A temperature compensated reference, high gain Error amplifier, current sensing comparator, and a high current totem pole output ideally suited for driving a power MOSFET. Also Included are protective features consisting of input and reference undervoltage lockouts each with hysteresis, cycle-by-cycle current limiting, programmable output deadtime, and latch for single pulse metering. *Trimmed Oscillator for Precise Frequency Control *Oscillator Frequency Guaranteed at 250kHz *Current Mode Operation to 500kHz *Automatic Feed Forward Compensation *latching PWM for Cycle-By-Cycle Current Limiting *Internally Trimmed Reference with Undervoltage Lockout *High Current Totem Pole Output *Undervoltage Lockout with Hysteresis *Low Startup and Operating Current Features Package Dimensions D GAUGE PLANE E REF. A A1 A2 b b1 b2 b3 c A Millimeter Min. Max. 0.381 2.921 0.356 0.356 1.143 0.762 0.203 0.5334 4.953 0.559 0.508 1.778 1.143 0.356 REF. c1 D E E1 e HE L Millimeter Min. Max. 0.203 0.279 9.017 10.16 6.096 7.112 7.620 8.255 2.540 BSC 10.92 2.921 3.810 SEATING PLANE Z Z b L SECTION Z - Z b e DIP-8 Function Pin1:Compensation Pin2:Voltage Feedback Pin3:Current Sense Pin4:RT/CT Pin5:Ground Pin6:Output Pin7:Vcc Pin8:Vref DIP-8L c Description This pin is the Error Amplifier output and is made available for loop compensation. This is the inverting input of the Error Amplifier. It’s normally connected to the Switching power supply output through a resistor divider. A voltage proportional to inductor current is connected to this input .The PWM uses this information to terminate the output switch conduction. The oscillator frequency and maximum output duty cycle are programmed by connecting resistor RT to Vref and capacitor CT to ground .Operation 500kHz is possible. This pin is the combined control circuitry and power ground. This output directly drives the gate of a power MOSFET. Peak currents up to 1 A are sourced and sunk by this pin. This pin is the positive supply of the control IC. This is the reference output .It provides charging current for capacitor CT through resistor RT. Absolute Maximum Ratings at Ta = 25 : Parameter Total power Supply and Zener current Output current,source or sink(note1) Output energy(capacitive load per cycle) Symbol (ICC+Iz) Io W VALUE 30 1.0 5.0 Unit mA A J 1/9 ISSUED DATE :2003/05/20 REVISED DATE :2004/09/30B Current sense and voltage feedback inputs Error Amplifier Output Sink Current P ower Dissipation at Thermal characteristics Storage Temperature Range Operating Junction Temperature Operating ambient Temperature Vin Io PD P JA Tstg TJ TA -0.3 to 5.5 10 702 178 -65 to 150 +150 0~+70 V mA mW : /W : : : Electrical Characteristics Parameter Reference Section Output Voltage Line Regulation Load Regulation Temperature. Stability Total Output Variation Output Noise Voltage Long Term Stability Output Short Circuit current Oscillator Section Frequency (0 : TA 70 : ,Vcc=15V[note 2],RT=10k,CT =3.3Nf,unless otherwise specified) SYMBOL VREF Regline Regload Ts VREF Vn S ISC Tj=25 : TA=0 : to 70 : Tj=25 : (RT =6.2k,CT =1.0nF) Line, Load, Temperature F=10kHz to 10Hz,Tj=25 : TA=125 : ,1000Hrs 4.82 -30 49 48 225 250 0.2 0.5 1.6 Tj=25 : TA = 0 : to 70 : Vo =2.5V VFB=5.0V Vo=2V to 4V Tj=25 : Vcc=12V to 25V Vo=1.1V,VFB=2.7V Vo=5.0V,VFB=2.3V VFB=2.3V,RL =15K to GND VFB=2.7V,RL =15K to Vref (Note 3,4) (Note 3) VCC= 12 to 25V (Note 3) 2.85 0.9 65 0.7 60 2.0 -0.5 5.0 7.8 7.6 2.42 8.3 8.8 8.8 2.58 -2.0 Test Conditions Tj=25 : ,Io=1mA Vcc=12V to 25V Io=1mA to 20mA Min 4.90 Typ. 5 2.0 3.0 0.2 50 5 -85 52 Max. 5.1 20 25 5.18 -180 55 56 275 1.0 % % V mA KHz Unit V mV mV mV/ : V V mV mA Frequency Change with Voltage Frequency Change with Temperature Oscillator Voltage Swing(Peak to Peak) Discharge Current Error Amplifier Section Voltage Feedback Input Input Bias Current Open Loop Voltage Gain Unity Gain Bandwidth P ower Supply Rejection Ratio Output Sink Current Output Source Current Output Voltage Swing High State Output Voltage Swing Low State Current Sense section Current Sense Input Voltage gain fosc/ V fosc/ T VOSC Idischg Vcc=12V to 25V TA = 0 : to 70 : VFB IIB AVOL BW PSRR Isink Isource VoH VOL Av 2.50 -0.1 90 1.0 70 12 -1.0 6.2 0.8 3.0 1.0 70 -2 150 0.1 1.6 V A dB MHz dB mA mA V 1.1 3.15 1.1 -10 300 0.4 2.2 V V/V V dB A ns V V V V Maximum Current Sense Input Threshold Vth PSRR P ower Supply Rejection Ratio Input Bias Current Propagation Delay Output Low Voltage Output High Level Output Voltage with UVLO Activated Output Voltage Rise Time Output Voltage Fall Time IIB Tplh(in/out) Current Sense Input to Output VOL Isink=20mA Isink=200mA VOH VOL (UVLO) tr tr Isource=20mA Isource=200mA VCC=6.0V,Isink=1.0mA Tj=25 : ,CL=1nF Tj=25 : ,CL=1nF 13 12 13.5 13.4 0.1 50 50 1.1 150 150 V ns ns 2/9 ISSUED DATE :2003/05/20 REVISED DATE :2004/09/30B Under-Voltage Lockout Section Startup Threshold PWM Section Maximum Duty Cycle Minimum Duty Cycle Total Device P ower Startup Supply Current P ower Operating Supply Current P ower Supply Zener Voltage ICC+IC ICC+IC Vz VCC=14V N ote 2 ICC=25mA 30 0.3 12 36 0.5 17 mA mA V DC(MAX) DC(MIN) 94 96 0 % % Vth 14.5 8.5 16 10 17.5 11.5 V V Min. Operating Voltage After Turn-on(VCC) VCC(min) N ote 1: Maximum Package power dissipation limits must be observed. Note 2: Adject Vcc above the Startup threshold before setting to 15V. Note 3: This parameter is measured at the latch trip point with VFB=0V. Note 4: Comparator gain is defined as:: AV V Output Compensation V Current Sense Input Characteristics Curve 3/9 ISSUED DATE :2003/05/20 REVISED DATE :2004/09/30B 4/9 ISSUED DATE :2003/05/20 REVISED DATE :2004/09/30B 5/9 ISSUED DATE :2003/05/20 REVISED DATE :2004/09/30B Application Information 6/9 ISSUED DATE :2003/05/20 REVISED DATE :2004/09/30B 7/9 ISSUED DATE :2003/05/20 REVISED DATE :2004/09/30B 8/9 ISSUED DATE :2003/05/20 REVISED DATE :2004/09/30B Important Notice: All rights are reserved. Reproduction in whole or in part is prohibited without the prior written approval of GTM. GTM reserves the right to make changes to its products without notice. GTM semiconductor products are not warranted to be suitable for use in life-support Applications, or systems. GTM assumes no liability for any consequence of customer product design, infringement of patents, or application assistance. Head Office And Factory: Taiwan: No. 17-1 Tatung Rd. Fu Kou Hsin-Chu Industrial Park, Hsin-Chu, Taiwan, R. O. C. TEL : 886-3-597-7061 FAX : 886-3-597-9220, 597-0785 China: (201203) No.255, Jang-Jiang Tsai-Lueng RD. , Pu-Dung-Hsin District, Shang-Hai City, China TEL : 86-21-5895-7671 ~ 4 FAX : 86-21-38950165 9/9