UTC3843A - UNISONIC TECHNOLOGIES

UTC3843A PWM Controller

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 .

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 5 GND OSCILLATOR ABSOLUTE MAXIMUM RATINGS(Ta=25°C) P.