The UC1825 family of PWM control ICs is optimized for high frequency switched mode power supply applications. Particular care was given to minimizing propagation delays through the comparators and logic circuitry while maximizing bandwidth and slew rate of the error amplifier. This controller is designed for use in either current-mode or voltage mode systems with the capability for input voltage feed-forward. Protection circuitry includes a current limit comparator with a 1V threshold, a TTL compatible shutdown port, and a soft start pin which will double as a maximum duty cycle clamp. The logic is fully latched to provide jitter free operation and prohibit multiple pulses at an output. An under-voltage lockout section with 800mV of hysteresis assures low start up current. During under-voltage lockout, the outputs are high impedance. These devices feature totem pole outputs designed to source and sink high peak currents from capacitive loads, such as the gate of a power MOSFET.
The UC1825 family of PWM control ICs is optimized for high‑frequency switched‑mode power‑supply applications. They support both voltage‑mode and current‑mode topologies, offering a 50 ns propagation delay, dual totem‑pole outputs up to 0.5 A, and a low start‑up current of 1.1 mA.
The datasheet details absolute maximum ratings, electrical characteristics, pin‑out diagrams, PCB layout recommendations, oscillator performance, and synchronization options for the UC1825, UC2825, and UC3825 devices.
| Propagation Delay to Output | 50 ns |
|---|---|
| Output Current (Source or Sink) | 0.5 A |
| Supply Voltage Range | 0‑30 V |
| Start‑Up Current | 1.1 mA |
The device has a propagation delay of 50 ns to the output.
The ICs can operate with a supply voltage from 0 V up to 30 V.
Each output pin can source or sink up to 0.5 A.