This document describes the features and characteristics of the FSFM260N / FSFM261N / FSFM300N Green-Mode Fairchild Power Switch (FPS™) products, including internal avalanche-rugged SenseFET, advanced burst-mode operation, precision fixed operating frequency, internal startup circuit, over-voltage protection, overload protection, internal thermal shutdown function, abnormal over-current protection, auto-restart mode, under-voltage lockout, and built-in soft-start.
The FSFM260N, FSFM261N, and FSFM300N are integrated Pulse Width Modulator (PWM) and SenseFET devices designed for high-performance offline Switch Mode Power Supplies (SMPS). These devices combine an avalanche-rugged SenseFET with a current-mode PWM control block to reduce component count and cost while increasing efficiency. They feature advanced burst-mode operation, consuming under 1W at 240Vac and 0.5W load.
| Operating Junction Temperature Limit | -25 to +85°C |
|---|---|
| Switching Frequency (Typical) | 67 kHz |
| Internal Soft-Start Time | 15ms |
| Low Operating Current (Typical) | 2.5mA |
The devices include Over-Voltage Protection (OVP), Overload Protection (OLP), Internal Thermal Shutdown (TSD), and Abnormal Over-Current Protection (AOCP).
The maximum practical continuous power in an open-frame design at 50°C ambient is 35W.
The internal high-voltage current source supplies bias once Vcc reaches 12V.