KA3843AC

www.DataSheet4U.com www.fairchildsemi.com KA3843AC SMPS Controller Features Low start current 0.2mA (typ) Operating range up to 500kHz Cycle by cycle current limiting Under voltage lock out with hysteresis Short shutdown delay time: typ.100ns High current totem-pole output Output swing limiting: 22V Description The KA3843AC are fixed PWM controller for Off-Line and DC to DC converter applications. The internal circuits include UVLO, low start up current circuit, temperature compensated reference, high gain error amplifier, current sensing comparator, and high current totem-pole output for driving a POWER MOSFET. Also KA3843AC provide low start up current below 0.3mA and short shutdown delay time typ. 100ns. The KA3843AC is 8.4V(on) and 7.6V(off). The KA3843AC can operate within 100% duty cycle. 8-DIP 1 8-SOP 1 Internal Block Diagram 7 VCC 29V VREF 8 Internal Bias 1/2VREF 5V VREF SET/ RESET UVLO 5 GND Good LOGIC 7 Error Amp + C.S PWM Comp. LATCH 1/3 1V S R 22V 6 OUTPUT PWR VC VFB 2 COMP 1 5 PWR C.S 3 RT/CT 4 T GND OSCILLATOR Rev. 1.0.1 ©2005 Fairchild Semiconductor Corporation www.DataSheet4U.com KA3843AC Absolute Maximum Ratings Parameter Supply voltage Output current Analog inputs (pin2, 3) Error amp. output sink current Power dissipation Symbol VCC IO VI(ANA) ISINK(EA) PD Value 30 +1 -0.3 to 6.3 10 1 Unit V A V mA W Electrical Characteristics (VCC = 15V, RT = 10KW, CT = 3.3nF, TA = 0°C to +70°C ,Unless otherwise specified) Parameter RE...