FSDL321

AC DC Converters, Offline Switchers Overview

The FSDL321 is a Green Mode Fairchild Power Switch (FPS) integrating a high-voltage avalanche rugged Sense FET with a current-mode PWM controller. It operates as an offline switching regulator for SMPS applications. Key electrical parameters include a maximum switching frequency of 50 kHz to 110 kHz, a breakdown voltage of 650 V, and a startup voltage of 12 V. The supply voltage range is 8 V to 20 V, with a maximum duty cycle of 77%. It supports a rated power of 17 W and functions within a temperature range of -25°C to 85°C.

AC DC Converters, Offline Switchers Feature Summary

• Integrates an avalanche rugged Sense FET with a current-mode PWM control block for minimal external component requirements.
• Features advanced Burst-Mode operation to achieve low standby power consumption in light-load conditions.
• Includes comprehensive protection mechanisms such as pulse-by-pulse current limiting, overvoltage, overload, and thermal shutdown.
• Utilizes frequency modulation to reduce electromagnetic interference (EMI) during operation.

AC DC Converters, Offline Switchers Applications

• Switch Mode Power Supplies (SMPS) for Set-Top Boxes (STB)
• Low-cost DVD player power supplies
• Auxiliary power supplies for personal computers

AC DC Converters, Offline Switchers Procurement Notes

Verify the specific manufacturer source, as the FSDL321 was originally a Fairchild Semiconductor product now part of onsemi. Confirm package type availability, typically 8-DIP or 8-SOP, against your board design requirements. Ensure compliance documentation matches the specific lot date code. Check for any patent restrictions or obsolescence notices associated with legacy inventory sources.

AC DC Converters, Offline Switchers Selection Notes

Select this component for cost-sensitive offline power designs requiring integrated high-voltage switching. The fixed operating frequency simplifies EMI filter design compared to variable frequency alternatives. Ensure the application load does not exceed the 17 W rated power capability. Verify that the input voltage range aligns with the 9 V to 20 V VCC operational window during startup and normal operation.

AC DC Converters, Offline Switchers Part Context

The FSDL321 belongs to the FPS™ (Fairchild Power Switch) family, specifically the FSDx321 series where 'x' denotes suffix variations like H or L. These devices are designed for high-performance offline switch-mode power supplies. The integration of the power switch and controller reduces board space and assembly costs compared to discrete solutions.

AC DC Converters, Offline Switchers Replacement Considerations

Direct substitutes include other members of the FSDx321 series, such as FSDL321L or FSDH321, which share similar functional architectures. Verify pin compatibility and thermal characteristics when cross-referencing with generic off-the-shelf replacements from other manufacturers offering equivalent green mode controllers.