This document describes the features and characteristics of UC2842A/3A/4A/5A family of control ICs. This family is suitable for offline and DC to DC converters, and it has features such as low start up current, trimmed oscillator discharge current, automatic feed forward compensation, and pulse-by-pulse current limiting.
The UC2842AQ family of current‑mode PWM controller ICs is a pin‑compatible, improved version of the UC2842/3/4/5 series. The devices are designed for off‑line and DC‑to‑DC converters, offering low start‑up current, trimmed oscillator discharge, and under‑voltage lockout with hysteresis.
The datasheet includes detailed electrical characteristics, PWM and error‑amplifier sections, mechanical dimensions, ordering part numbers for SOIC‑8 and SOIC‑14 packages, and an important notice covering warranty and safety‑critical usage. Additional application notes and package drawings are referenced on the TI website.
| Start‑up current | <0.5 mA |
|---|---|
| Maximum duty cycle (UC2842A/UC2843A) | 100 % |
| Maximum duty cycle (UC2844A/UC2845A) | 50 % |
| Typical output voltage (25 °C, 1 mA load) | 5.0 V |
| Line regulation voltage | 20 mV |
The start‑up current is guaranteed to be less than 0.5 mA.
The typical output voltage is 5.0 V.
The line regulation voltage is specified as 20 mV over a 12 V to 25 V input range.