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UTCUC3842A Dataheets PDF



Part Number UTCUC3842A
Manufacturers Unisonic Technologies
Logo Unisonic Technologies
Description CURRENT MODE PWM CONTROL CIRCUITS
Datasheet UTCUC3842A DatasheetUTCUC3842A Datasheet (PDF)

UTC UC3842A / 3843A LINEAR INTEGRATED CIRCUIT CURRENT MODE PWM CONTROL CIRCUITS 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 a minimal external part count SOP-8 FEATURES *Low external part count. *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 .

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UTC UC3842A / 3843A LINEAR INTEGRATED CIRCUIT CURRENT MODE PWM CONTROL CIRCUITS 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 a minimal external part count SOP-8 FEATURES *Low external part count. *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 BLOCK DIAGRAM 7 Vcc Vref 8 Internal Bias 1/2Vref 5V REF S/R 5 GND Vref Good Logic 1/3Vref U.V.L.O CURRENT SENSE COMPARATOR R PWM LATCH S 7 Vcc VFB COMP 2 1 ERROR AMPLIFIER 1V 6 OUTPUT CURRENT SENSE 3 RT/CT 4 OSCILLATOR 5 GND ABSOLUTE MAXIMUM RATINGS(Ta=25°C) PARAMETER Supply Voltage(Low Impedance Source) Supply Voltage(Icc<30mA) Output Current ( Peak ) Output Energy(capacity Load) Analog Inputs(pin 2,3) Error Amplifier Output Sink Current Power Dissipation Lead Temperature( Soldering 10 Sec ) SYMBOL VCC Vcc Io VI(ANA) ISINK(EA) PD DIP-8 SOP-8 Tlead VALUE 30 Self Limiting +-1 5 -0.3 ~ +6.3 10 at Tamb<=25°C 1.0 at Tamb<=25°C 0.5 300 UNIT V V A µJ V mA W W °C UTC UNISONIC TECHNOLOGIES CO., LTD. 1 QW-R103-002,A UTC UC3842A / 3843A LINEAR INTEGRATED CIRCUIT (continued) PARAMETRER Storage Temperature Note 1: Ta>25°C, PD derated with 8mW/°C. SYMBOL Tstg VALUE -65 ~ +150 UNIT °C 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 SYMBOL VREF ∆VREF ∆VREF TEST CONDITIONS Tj=25°C,Io=1mA 12<=VIN<=25V 1<=Io=20mA (Note 2) Line, Load, Temp(note 2) 10Hz<=f<=10kHz,Tj=25°C (note 2) Ta=25°C,1000Hrs(note 2) 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 3 1 70 -2 150 0.1 1.5 13.5 13.5 50 50 16 8.4 10 7.6 97 MAX 5.1 20 25 0.4 5.18 25 -180 57 1 UNIT V mV mV mV/°C V uV mV mA kHz % % V V µA dB MHz dB mA mA V V V/V V dB µA ns V V V V ns ns V V 4.82 Vosc ISC f ∆f/∆Vcc Vosc VI(EA) IBIAS -30 47 Oscillator Section Initial Accuracy Voltage Stability Temperature Stability Amplitude Tj=25°C 12<=Vcc<=25V Tmin<=TA<=Tmax(note 2) Vpin 4 peak to peak Vpin 1=2.5V 2 <=Vo<=4V Tj=25°C (note 2) 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 (note 3,4) Vpin 1=5V( note 3) 12<=Vcc<=25V Vpin 3=0 to 2V VOL VOH tR tF VTH(ST) VOPR(min) Isink=20mA Isink=200mA Isource=20mA Isource=200mA Tj=25°C,CL=1nF(note 2) Tj=25°C,CL=1nF(note 2) UTC3842A UTC3843A After Turn On UTC3842A UTC3843A Error Amplifier Section Input Voltage Input Bias Current AVOL Unity Gain Bandwidth PSRR Output Sink Current Output Source Current Vout High Vout Low 2.42 60 0.7 60 2 -0.5 5 2.58 -2 Isink Isource VOH VOL GV VI(MAX) IBIAS 1.1 3.15 1.1 -10 300 0.4 2.2 Current Sense section Gain Maximum Input signal PSRR Input Bias Current Delay to Output 2.85 0.9 Output Section Output Low Level Output High Level Rise Time Fall Time Start Threshold Min. Operating Voltage 13 12 150 150 17.5 9 11.5 8.2 100 Under-Voltage Lockout Output Section 14.5 7.8 8.5 7 95 V % PWM Section Maximum Duty Cycle D(MAX) UTC UNISONIC TECHNOLOGIES CO., LTD. 2 QW-R103-002,A UTC UC3842A / 3843A LINEAR INTEGRATED CIRCUIT PARAMETER Minimum Duty Cycle SYMBOL D(MIN) TEST CONDITIONS MIN TYP MAX 0 UNIT % Total Standby Current Start-up Current IST Operating Supply Current ICC(opr) Vpin 2=Vpin 3=0V Vcc Zener Voltage Vz Icc=25mA note 2:These parameters, although guaranteed ,are not 100% tested in production. note 3:Parameters measured at trip point of latch with Vpin 2=0. note 4:Gain defined as: 0.12 11 34 0.3 17 mA mA V A= ∆Vpin 1 ∆Vpin 3 ; 0<=Vpin3<=0.8V note 5:Adjust Vcc above the start threshold before setting at 15V. OPEN-LOOP LABORATORY TEST FIXTURE Vref 4.7kΩ RT 100kΩ 0.1 µF Error Amp Adjust Isense Adjust 4.7kΩ 2 3 5kΩ 7 6 5 0.1 µF 1 8 A Vcc 1kΩ / 1W OUTPUT 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 ON/OFF Command to rest of IC <15mA 7 Von=16V Voff=10V <1mA Voff Von Vcc During Under-Voltage Lockout, the output driver is biased to a high impedance state. Pin 6 should be shunt to GND with a bleeder resistor to prevent activating the power switch with output leakage currents. UTC UNISONIC TECHNOLOGIES CO., LTD. 3 QW-R103-002,A UTC UC3842A / 3843A LINEAR INTEGRATED CIRCUIT ERROR AMPLIFIER CONFIGURATION 2.5V 0.5mA Zi Zf 2 1 Error amplifier ca.


UTCTL494 UTCUC3842A UTCUC3843A


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