1FEATURES

• QML-V Qualified, SMD 5962-86704

• Rad-Tolerant: 50 kRad (Si) TID (ELDRS Free) (1)

• Controlled Baseline

• Optimized For Off-line and DC-to-DC

Converters

• Low Start-Up Current (<1 mA)

• Automatic Feed Forward Compensation

• Pulse-by-Pulse Current Limiting

• Enhanced Load Response Characteristics

• Under-Voltage Lockout With Hysteresis

• Double Pulse Suppression

• High Current Totem Pole Output

• Internally Trimmed Bandgap Reference

• 500-kHz Operation

• Low RO Error Amp

DESCRIPTION

The UC1843 family of control devices 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 under-voltage lockout featuring start up current less than 1 mA, 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. The under-voltage lockout threshold is

8.4 V and maximum duty cycle range is around 100%.