DESCRIPTION

The UC384XT family of control ICs provides the necessary features to implement off-line or DC to DC fixed frequency current mode control schemes with a minimal external parts count. Internally imple mented circuits include a trimmed oscillator for precise DUTY CYCLE CONTROL under voltage lock out featuring start-up current less than 0.5mA, a precision reference trimmed for accuracy at the error amp input, logic to insure latched operation, a PWM comparator which also provides current limit control, and a totem pole output stage designed to source or sink high peak current. The output stage, suitable

for driving N-Channel MOSFETs, is low in the off state.

. 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 START-UP AND OPERATING CURRENT