KA3842AE

KA3842AC/KA3842AE SMPS Controller March 2006 KA3842AC/KA3842AE SMPS Controller Features „ Low start current 0.2mA (Typ.) „ Operating range up to 500kHz „ Cycle by cycle current limiting „ Under Voltage Lock Out (UVLO) with hysteresis „ Short shutdown delay time: Typ.100ns „ High current totem-pole output „ Output swing limiting: 22V Description The KA3842AC/KA3842AE are fixed PWM controllers for Off Line and DC to DC converter applications. The internal circuits include UVLO, low start up current, temperature compensated reference, high gain error amplifier, current sensing comparator, and high current totem pole output for driving a POWER MOSFET. Also KA3842AC/KA3842AE provides low start up current below 0.3mA and short shutdown delay time, typically 100ns. The KA3842AC/KA3842AE has a UVLO threshold of 16V(on) and 10V(off). The KA3842AC/KA3842AE can operate within a 100% duty cycle. 1 8-DIP Ordering Information Part Number KA3842AC KA3842AE Operating Temp. Range -0 to +70°C Pb-Free Yes Package 8-DIP Packing Method Tube ©2006 Fairchild Semiconductor Corporation 1 www.fairchildsemi.com KA3842AC/KA3842AE Rev. 1.0.1 KA3842AC/KA3842AE SMPS Controller Internal Block Diagram 7 VCC 29V VREF 8 Internal Bias 1/2 VREF Error Amp + C.S PWM Comp. LATCH 1/3 1V S COMP 1 T 5 PWR GND R 22V 6 OUTPUT 5V VREF SET/ RESET UVLO Good LOGIC 7 PWR VC 5 GND VFB 2 C.S 3 RT/CT 4 OSCILLATOR KA3842AC/KA3842AE Rev. 1.0.1 2 www.fairchildsemi.com KA3842AC/KA3842AE SMPS Controller Abs...