This document introduces the improved versions of UC3823/UC3825 PWMs. These versions have better performance than the traditional UC3823/UC3825, including: compatible with voltage-mode or current-mode control methods, practical operation at switching frequencies to 1 MHz, 50-ns propagation delay to output, high-current dual totem pole outputs (2-A peak), trimmed oscillator discharge current, low 100-µA startup current, pulse-by-pulse current limiting comparator and latched overcurrent comparator with full cycle restart.
This data sheet describes the UC3823A, UC3823B, UC3825A, and UC3825B family of PWM controllers. It lists improved features such as operation up to 1 MHz switching frequency, low 100 µA startup current, and dual totem‑pole outputs capable of 2 A peak current.
Technical details include pin assignments, electrical characteristics, UVLO and soft‑start behavior, leading‑edge blanking, and recommended external components. The document also gives design equations for timing resistor and capacitor selection and outlines fault management and synchronization methods.
| Startup current | 100 µA (typical) |
|---|---|
| Supply voltage (VCC) | 12 V |
| Operating temperature range | 0 °C to 70 °C (UC3823x/UC3825x) |
| Maximum duty cycle | 85 % |
| Output peak current | 2 A per channel |
The typical startup supply current is about 100 µA.
The devices support a maximum duty cycle of 85 %.
Each totem‑pole output can deliver a 2 A peak current into a capacitive load.
Version B devices have UVLO thresholds of 16 V and 10 V.