HIGH PERFORMANCE CURRENT MODE PWM CONTROLLERS

DESCRIPTION

The UTC UC1842B/1843B are high performance fixed

frequency current mode controllers that specifically designed for

Off-Line and DC to DC converter applications with minimal external

parts count.

The differences between UC1842B and UC1843B are the

under-voltage lockout thresholds. The UC1842B ideally suited to

off-line applications with UVLO thresholds of 16V(ON) and 10V(OFF),

and UC1843B has UVLO thresholds of 8.4V(ON) and 7.6V(OFF) for

lower voltage applications.

FEATURES

* Operation output switching frequency up to 500 kHz

* Automatic feed forward compensation

* Latching PWM for cycle-by-cycle current limiting

* High current totem pole output

* Internally trimmed reference with under voltage lockout

* UVLO with hysteresis

* Low startup and operating current