UC3842A-S08-T

UNISONIC TECHNOLOGIES CO., LTD UC3842A/3843A CURRENT MODE PWM CONTROL CIRCUITS SOP-8 LINEAR INTEGRATED CIRCUIT DESCRIPTION The UTC UC3842A/3843A provide the necessary functions to implement off-line or DC to DC fixed frequency current mode , controlled switching circuits with minimal external components. FEATURES *Low start up current ( Typical 0.12mA ) *Automatic feed forward compensation *Pulse-by-Pulse current limiting *Under-voltage lockout with hysteresis *Double pulse Suppression *High current totem pole output to drive MOSFET directly *Internally trimmed band gap reference *500kHz operation DIP-8 *Pb-free plating product number: UC3842AL UC3843AL ORDERING INFORMATION Ordering Number Normal Lead Free Plating UC3842A-D08-T UC3842AL-D08-T UC3842A-S08-R UC3842AL-S08-R UC3842A-S08-T UC3842AL-S08-T UC3843A-D08-T UC3843AL-D08-T UC3843A-S08-R UC3843AL-S08-R UC3843A-S08-T UC3843AL-S08-T Package DIP-8 SOP-8 SOP-8 DIP-8 SOP-8 SOP-8 Packing Tube Tape Reel Tube Tube Tape Reel Tube UC3842AL-D08-T (1)Packing Type (2)Package Type (3)Lead Plating (1) T: Tube, R: Tape Reel (2) D08: DIP-8, S08: SOP-8 (3) L: Lead Free Plating, Blank: Pb/Sn www.unisonic.com.tw Copyright © 2005 Unisonic Technologies Co., Ltd 1 of 9 QW-R103-002,D UC3842A/3843A PIN CONFIGURATION COMP 1 LINEAR INTEGRATED CIRCUIT 8 VREF VFB 2 7 VCC Current Sense 3 6 Output R T/CT 4 5 GND BLOCK DIAGRAM 7 Vcc VREF 8 Internal Bias 1/2VREF 5V REF S/R 5 GND U.V.L.O CURRENT SENSE COMPARATOR R PWM LATCH S VREF Good Logic 1/3VREF 7 Vcc VFB COMP CURRENT SENSE 2 1 3 ERROR AMPLIFIER 1V 6 OUTPUT 5 RT/CT 4 OSCILLATOR GND UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw 2 of 9 QW-R103-002,D UC3842A/3843A ABSOLUTE MAXIMUM RATINGS (Ta=25℃) PARAMETER Supply Voltage(Low Impedance Source) Supply Voltage(ICC25°C PD 8 mW/°C Junction Temperature TJ +150 °C Storage Temperature TSTG -65 ~ +150 °C Note Absolute maximum ratings are those values beyond which the device which the device could be permanently damaged. Absolute maximum ratings are stress ratings only and functional device operation is not implied. RATINGS 30 Self Limiting ±1 ELECTRICAL CHARACTERISTICS (0°C≦Ta≦70°C, VCC=15V, RT=10kΩ, CT=3.3nF, unless otherwise specified) PARAMETER Reference Section Output Voltage Line Regulation Load Regulation Temperature Stability Total Output Variation Output Noise Voltage Long Term Stability Output Short Circuit Oscillator Section Initial Accuracy Voltage Stability Temperature Stability Amplitude Error Amplifier Section Input Voltage Input Bias Current AVOL Unity Gain Bandwidth PSRR Output Sink Current Output Source Current VOUT High VOUT Low SYMBOL VREF ∆VREF ∆VREF TEST CONDITIONS TJ=25°C,IOUT=1mA 12≦VIN25V 1≦IOUT=20mA (Note 1) Line, Load, Temp(Note 1) 10Hz≦f≦10kHz,TJ=25°C (Note 1) Ta=25°C,1000Hrs(Note 1) MIN 4.9 TYP 5 6 6 0.2 50 5 -100 52 0.2 5 1.7 2.50 -0.3 90 1 70 6 -0.8 6 0.7 MAX 5.1 20 25 0.4 5.18 25 -180 57 1 UNIT V mV mV mV/°C V µV mV mA kHz % % V V µA dB MHz dB mA mA V V 4.82 Vosc ISC -30 47 f TJ=25°C ∆f/∆Vcc 12≦VCC≦25V Tmin≦Ta≦Tmax(Note 1) Vosc Vpin 4 peak to peak VI(EA) II(BIAS) Vpin 1=2.5V 2 ≦VOUT≦4V TJ=25°C (Note 1) I2≦VCC≦25V Vpin 2=2.7V,Vpin 1=1.1V Vpin 2=2.3V,Vpin 1=5V Vpin 2=2.3V, RL=15kΩ to GND Vpin 2=2.7V,Vpin 1=1.1V 2.42 60 0.7 60 2 -0.5 5 2.58 -2 IO(SINK) IO(SOURCE) VOH VOL 1.1 UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw 3 of 9 QW-R103-002,D UC3842A/3843A ELECTRICAL CHARACTERISTICS(Cont.) PARAMETER Current Sense section Gain Maximum Input signal PSRR Input Bias Current Delay to Output Output Section Low Output Level High VOH SYMBOL GV VI(MAX) IBIAS Vpin 3=0 to 2V IO(SINK)=20mA IO(SINK)=200mA IO(SOURCE)=20mA IO(SOURCE)=200mA TJ=25°C,CL=1nF(Note 1) TJ=25°C,CL=1nF(Note 1) LINEAR INTEGRATED CIRCUIT TEST CONDITIONS (Note 2,3) Vpin 1=5V( Note 2) 12≦VCC≦25V MIN 2.85 0.9 TYP 3 1 70 -2 150 0.1 1.5 13.5 13.5 50 50 16 8.4 10 7.6 97 MAX 3.15 1.1 -10 300 0.4 2.2 UNIT V/V V dB µA ns V V V V ns ns V V V V % % mA mA V VOL 13 12 Rise Time tR Fall Time tF Under-Voltage Lockout Output Section 3842A Start Threshold VTH(ST) 3843A 3842A Min. Operating Voltage VOPR(MIN) After Turn On 3843A PWM Section MAX D(MAX) Duty Cycle Min D(MIN) Total Standby Current Start-up Current IST Operating Supply Current ICC(OPR) Vpin 2=Vpin 3=0V VCC Zener Voltage Vz ICC=25mA Note:1.These parameters, although guaranteed ,are not 100% tested in production. 2. Parameters measured at trip point of latch with Vpin 2=0. 3. Gain defined as: A= ∆Vpin 1 ∆Vpin 3 ; 0≦Vpin3≦0.8V 150 150 17.5 9 11.5 8.2 100 0 0.3 17 14.5 7.8 8.5 7 95 0.12 11 34 4. Adjust VCC above the start threshold before setting at 15V. UNISONIC TECHNOLOGIES CO., LTD www.unisonic.com.tw 4 of 9 QW-R103-002,D UC3842A/3843A OPEN-LOOP LABORATORY TEST FIXTURE LINEAR INTEGRATED CIRCUIT VREF 4.7kΩ RT 100kΩ 0.1 µF 1 2 3 8 7 6 5 A 0.1 µF Vcc Error Amp Adjust 4.7kΩ Isense Adjust 1kΩ / 1W OUTPUT 5kΩ 4 CT High peak current associated with capacity loads necessitate careful grounding techniques. Timing and bypass capacitors should be connected close to pin 5 in single point GND. The transistor and 5kΩ potentio-meter are used to sample the oscillator waveform and apply an adjustable Ramp to Pin 3. UNDER-VOLTAGE LOCKOUT Icc Vcc