UC2845

UC2842/3/4/5 ® UC3842/3/4/5 CURRENT MODE PWM CONTROLLER . OPTIMIZED FOR OFF-LINE AND DC TO DC CONVERTERS . LOW START-UP CURRENT (< 1 mA) . AUTOMATIC FEED FORWARD COMPENSA- TION . PULSE-BY-PULSE CURRENT LIMITING . ENHANCED LOAD RESPONSE CHARAC- TERISTICS . UNDER-VOLTAGE LOCKOUT WITH HYSTERESIS . DOUBLE PULSE SUPPRESSION . HIGH CURRENT TOTEM POLE OUTPUT . INTERNALLY TRIMMED BANDGAP REFER- ENCE . 500 KHz OPERATION . LOW RO ERROR AMP DESCRIPTION TheUC3842/3/4/5family of controlICs provides the necessary features to implement off-line or DC to DC fixed frequency current mode control schemes with a minimal externalparts count.Internallyimplementedcircuits include undervoltagelockout featuring start-up current less than 1 mA, a precision reference trimmed for accuracy at the error amp input, Minidip SO14 logic to insure latched operation, a PWM comparatorwhich also providescurrentlimit control,and a totem pole output stage designed to source or sink high peak current. The output stage, ...