FSQ311

AC DC Converters, Offline Switchers Overview

The FSQ311 is a high-voltage switch-mode power supply controller manufactured by onsemi, formerly Fairchild Semiconductor. It integrates a 700 V MOSFET and supports flyback topology for AC/DC conversion. Key electrical parameters include a maximum switching frequency of 65 kHz, a startup current of 2.5 mA, and an operating supply voltage range of 9 V to 36 V. The device features cycle-by-cycle current limiting with hysteresis and thermal shutdown protection.

AC DC Converters, Offline Switchers Feature Summary

• Integrates a high-voltage 700 V MOSFET for compact design
• Includes built-in cycle-by-cycle current limiting
• Provides thermal shutdown protection for reliability

AC DC Converters, Offline Switchers Applications

• Adapters and chargers
• Standby power supplies
• General-purpose offline switched-mode power supplies

AC DC Converters, Offline Switchers Procurement Notes

Verify the manufacturer origin as the part was originally produced by Fairchild Semiconductor before its acquisition by onsemi. Confirm package type and marking codes against official datasheets to distinguish between original Fairchild and current onsemi production runs. Ensure compliance with RoHS directives if required for the specific application region.

AC DC Converters, Offline Switchers Selection Notes

Select this component for low-power offline applications requiring integrated high-voltage switching. Evaluate thermal performance due to the internal MOSFET integration. Compare pin compatibility with legacy designs when transitioning from older Fairchild inventory to current onsemi-supplied units.

AC DC Converters, Offline Switchers Part Context

The FSQ311 belongs to the QX series of high-voltage switch-mode power supply controllers. This series is designed for cost-effective, high-reliability power solutions in consumer electronics and industrial equipment. The integration of the power switch reduces external component count and board space requirements.