1FEATURES

· –55°C to 125°C Known Good Die

· 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%.