DESCRIPTION

The UTC UC3842B/3843B are specifically designed for off-line and dc-to-dc converter applications offering the designer a cost-effective solution with minimal external components.

The UC3842B has UVLO thresholds 16V (on) and 10V(off), ideally suited for off-line converters. The UC3843B is tailored for lower voltage applications having UVLO thresholds of 8.4V(on) and 7.6V(off).

FEATURES

* Trimmed oscillator for precise frequency control

* Oscillator frequency guaranteed at 250kHz

* Current mode operation to 500kHz

* Automatic feed forward compensation

* Latching PWM for cycle-by-cycle current limiting

* Internally trimmed reference with undervoltage lockout

* High current totem pole output

* Undervoltage lockout with hysteresis

* Low startup and operating current