L4986A

Overview

The L4986A is a peak current-mode Power Factor Correction (PFC) controller designed for Continuous Conduction Mode (CCM) boost converters. It features an 800 V high-voltage startup block with integrated X-capacitor discharge circuitry, enabling compliance with safety standards like IEC 61010-1 and IEC 62368-1 without external discharge resistors. The device utilizes a proprietary multiplier emulator and THD optimizers to ensure low Total Harmonic Distortion across all operating conditions. Operating at a fixed switching frequency of 65 kHz, it supports power ranges from hundreds of watts to several kilowatts.

Feature Summary

• Proprietary off-time modulator ensures quasi-fixed frequency operation in CCM mode
• Integrated 800 V high-voltage startup with active input filter capacitor discharge
• Advanced protection against feedback loop failures, overvoltage, and boost inductor saturation
• Low consumption and disable functions for energy-saving compliance

Applications

• SMPS front-end converters up to 1 kW
• Medical equipment power supplies
• LED drivers and luminaires
• Desktop and server power supply units

Procurement Notes

Verify the specific suffix 'A' corresponds to the 65 kHz switching frequency variant when ordering. Confirm package type availability matches design requirements. Ensure compatibility with bridgeless or standard boost topologies based on application needs. Check RoHS compliance status for regulatory adherence. Validate that the high-voltage startup range aligns with system input specifications.

Selection Notes

Select the L4986A for applications requiring low component count and high efficiency in CCM PFC designs. The integrated X-capacitor discharge simplifies EMI filter design and reduces bill of materials. Ideal for systems needing robust protection against transient overvoltages and inductor saturation. Suitable for meeting strict harmonic distortion regulations such as EN61000-3-2 Class D.

Part Context

Part of the STMicroelectronics L4986 series of CCM PFC controllers. Designed to replace older solutions by integrating high-voltage startup and advanced protection features. Complements other ST PMICs for complete power management solutions. Offers a balance between performance and simplicity for mid-to-high power applications.

Replacement Considerations

L4986B serves as the alternative variant within the same family, offering a 130 kHz switching frequency instead of 65 kHz. Both share identical pinouts and core functionality but differ in operating frequency. Verify thermal and EMI implications when substituting between A and B variants.