The LT3781 is a high voltage synchronous switch regulator from Linear Technology. This product has high voltage operation, synchronous operating frequency and output switch phase, synchronous switch output, undervoltage lockout protection, fixed frequency operation, local ±1% voltage reference, input overvoltage protection, low start-up current, programmable start inhibit, etc.
The LT3781 is a high‑voltage synchronous dual‑transistor forward controller designed for DC/DC converters up to 72 V. It features programmable frequency up to 350 kHz, undervoltage lockout, soft‑start control, and optocoupler support, making it suitable for automotive, telecom, and backup power applications.
The document includes absolute maximum ratings, detailed electrical characteristics, pin descriptions, typical performance curves, package dimensions, and a list of related Linear Technology parts for reference.
| Maximum Input Voltage | 72 V |
|---|---|
| Maximum Operating Frequency | 350 kHz |
| Package | 20‑lead Plastic SSOP |
| Undervoltage Lockout Threshold (typical) | 8.4 V |
| Shutdown Pin Threshold (typical) | 1.25 V |
The LT3781 can operate with input voltages up to 72 V.
The controller can be programmed to run at frequencies up to 350 kHz.
It is supplied in a 20‑lead plastic SSOP package.