L6668TR

AC DC Converters, Offline Switchers Overview

The L6668TR is a current-mode primary controller IC designed for single-ended flyback converters. It operates at a fixed switching frequency of 100 kHz and supports a maximum duty cycle of 75%. The device provides one output with a voltage rating of 5 V and an output current capacity of 800 mA. It features on-board high-voltage start-up and low quiescent current to ensure compliance with energy-saving regulations. The component functions within a temperature range of -25°C to +150°C TJ and is housed in a 16-SO package.

AC DC Converters, Offline Switchers Feature Summary

• Implements load-dependent current-mode control with fixed-frequency operation at heavy loads, frequency foldback at light loads, and burst-mode at no-load to minimize standby consumption.
• Includes an interface with PFC controllers to disable pre-regulators when load levels fall below specific thresholds, ensuring compliance in power-factor-corrected systems.
• Provides comprehensive protection mechanisms including latched disable for overvoltage and overtemperature shutdown, pulse-by-pulse and hiccup-mode overcurrent protection, and slope compensation for stability.

AC DC Converters, Offline Switchers Applications

• Offline AC-DC converters requiring flyback topology
• Power supplies compliant with Blue Angel, Energy Star, and EU Code of Conduct standards
• Systems integrating power-factor correction (PFC) controllers

AC DC Converters, Offline Switchers Procurement Notes

Verify the exact suffix designation against the manufacturer's official documentation to confirm packaging type and reel specifications. Ensure that the procurement channel provides valid traceability data consistent with STMicroelectronics' quality standards. Confirm RoHS3 compliance status through the latest environmental declaration files before finalizing orders.

AC DC Converters, Offline Switchers Selection Notes

Select this component for applications requiring efficient standby power management and robust protection features in flyback designs. Consider the 16-SO package constraints and the requirement for external programming of peak current during burst-mode operation. Evaluate thermal performance within the specified junction temperature range and verify compatibility with the intended PFC controller interface if applicable.

AC DC Converters, Offline Switchers Part Context

The L6668 belongs to a series of smart primary controllers from STMicroelectronics, utilizing MultiPower BCD technology. It is specifically engineered for offline switchers where low quiescent current and high noise immunity are critical. The device integrates a totem-pole gate driver with internal clamp and UVLO pull-down, distinguishing it from basic PWM controllers by its advanced load-dependent control strategies.

AC DC Converters, Offline Switchers Replacement Considerations

Public confirmed substitute part numbers: None identified in provided documentation.