SG6961SZ

Overview

The SG6961SZ is an 8-pin boundary mode PFC controller IC designed for controlling PFC pre-regulators. It provides controlled on-time PWM to regulate output DC voltage and achieve natural power factor correction. The maximum on-time of the external switch is programmable to ensure safe operation during AC brownouts. An innovative multi-vector error amplifier ensures rapid transient response and precise output voltage clamping. A built-in circuit disables the controller if the output feedback loop opens. The start-up current is lower than 20µA, operating current is under 4.5mA, and supply voltage can reach up to 20V.

Feature Summary

• Boundary Mode PFC Controller
• Low Input Current THD
• Controlled On-Time PWM
• Zero-Current Detection

Applications

• Electric Lamp Ballasts
• AC-DC Switching Mode Power Converter
• Open-Frame Power Supplies and Power Adapters
• Flyback Power Converters with ZCS/ZVS

Procurement Notes

Verify manufacturer origin as Fairchild Semiconductor or acquired entity onsemi. Confirm package type matches SOP-8 specifications. Check RoHS compliance status against current regulatory requirements. Validate part authenticity through authorized distribution channels only. Ensure datasheet version aligns with design specifications.

Selection Notes

Select based on boundary mode control requirements for PFC applications. Consider low input current THD performance needs. Evaluate programmable maximum on-time capabilities for brownout protection. Assess multi-vector error amplifier benefits for transient response. Verify supply voltage range compatibility with system design constraints.

Part Context

The SG6961 belongs to a family of PFC controllers offering boundary mode operation. It integrates features like zero-current detection and cycle-by-cycle current limiting. The device supports leading-edge blanking instead of RC filtering. Output over-voltage clamping protection is included. Clamped gate output voltage ensures reliable switching operation.

Replacement Considerations

SG6961MY by onsemi serves as a direct replacement within the same product family.