L4985ATR

Overview

The L4985ATR is a continuous conduction mode (CCM) power factor controller designed for boost converters. It features an 800 V high-voltage startup block and proprietary THD optimization to ensure low harmonic distortion across all operating conditions. The device operates at a switching frequency of 65 kHz, suitable for applications ranging from hundreds of watts to several kilowatts. It includes integrated X-capacitor discharge circuitry to meet safety standards without external resistors. Protection mechanisms cover overvoltage, feedback loop faults, inductor saturation, and brownout events compliant with medical regulations.

Feature Summary

• Proprietary multiplier emulator and THD optimizer for minimal total harmonic distortion
• Integrated 800 V high-voltage startup with active X-capacitor discharge
• Totem-pole output stage capable of driving large MOSFETs or IGBTs
• Comprehensive protection including OVP, OCP, and brownout support

Applications

• SMPS pre-regulators compliant with EN61000-3-2 Class-D
• Power supplies adhering to JEITA-MITI Class-D standards
• Medical equipment requiring IEC 60601-1-2 compliance
• High-efficiency power systems meeting Energy Star and DoE guidelines

Procurement Notes

Verify the suffix 'ATR' corresponds to the specific tape-and-reel packaging configuration and temperature grade defined in the official datasheet. Confirm that the 65 kHz switching frequency variant matches the system design requirements. Ensure compatibility with the SO8 package footprint during PCB layout validation. Cross-reference the ordering code with the manufacturer's current product availability status to avoid obsolete stock issues.

Selection Notes

Select this component for CCM PFC applications requiring low component count and high efficiency. The integrated startup and discharge features simplify EMI filter design. The 65 kHz frequency option is appropriate for medium-power ranges up to several kilowatts. Consider the totem-pole drive capability when selecting external switching devices. Verify that the input voltage range and output power requirements align with the controller's operational limits.

Part Context

The L4985 belongs to a family of peak current-mode PFC controllers offering high performance with minimal external components. It addresses stringent harmonic standards through advanced control algorithms. The device supports both A (65 kHz) and B (130 kHz) frequency options. It is designed for wide-range input voltages and provides robust protection features for critical power supply applications.

Replacement Considerations

The L4986 is a functionally similar controller within the same family, offering identical core features and protection schemes. Both devices share the same pinout and control architecture. Selection between variants should focus on specific frequency requirements or packaging preferences as defined in the official substitution guidelines.