ML4812CQ

Overview

The ML4812CQ is a current-mode power factor correction controller manufactured by Fairchild Semiconductor. It integrates a high-voltage startup circuit, an error amplifier, and a PWM comparator to regulate input current waveform. The device operates from a wide supply voltage range and includes protection features such as cycle-by-cycle current limiting and undervoltage lockout. Designed for universal AC line applications, it facilitates efficient power conversion with low harmonic distortion.

Feature Summary

• Integrates a high-voltage startup circuit for simplified design
• Provides cycle-by-cycle peak current limiting for robust operation
• Includes undervoltage lockout to prevent malfunction during low input conditions

Applications

• Universal AC-DC power supplies
• Power factor correction stages in computer peripherals
• Telecommunications power systems

Procurement Notes

Verify the manufacturer origin as Fairchild Semiconductor, now part of ON Semiconductor, to ensure component authenticity. Confirm the suffix 'CQ' corresponds to the specific commercial temperature grade and SOIC-16 package variant. Cross-reference the datasheet revision date to ensure compatibility with current design specifications and regulatory standards.

Selection Notes

Select this component for designs requiring integrated PFC control without external startup resistors. Evaluate the thermal performance within the SOIC-16 package against the expected power dissipation. Ensure the input voltage range matches the application's rectified AC line specifications and verify that the current sensing requirements align with the internal comparator thresholds.

Part Context

This component belongs to the ML48xx series of power factor correction controllers. These devices are engineered to improve efficiency in switching power supplies by shaping the input current to follow the input voltage waveform. The series is widely used in consumer electronics and industrial equipment to meet electromagnetic interference regulations.

Replacement Considerations

Check for direct pin-compatible alternatives within the ON Semiconductor portfolio, such as the NCP1653 or similar current-mode PFC controllers. Verify that any substitute maintains the same operating frequency range and protection feature set.