UC3842BD1 PWM controller, 11 V - 30 Vi, 500kHz, 1.6 ... 13 Vout, SO-8

High Performance Current Mode PWM Controller

Description: The UC384xB 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 implemented circuits include a trimmed oscillator for precise DUTY CYCLE CONTROL under voltage lockout 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 offstate. Differences between members of this family are the under-voltage lockout thresholds and maximum duty cycle ranges. The UC3842B and UC3844B have UVLO thresholds of 16V (on) and 10V (off), ideally suited off-line applications The corresponding thresholds for the UC3843B and UC3845B are 8.5 V and 7.9 V. The UC3842B and UC3843B can operate to duty cycles approaching 100%. A range of the zero to 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 START-UP AND OPERATING CURRENT