TOP257YN Off-line Switcher IC

The TOP257YN Off-Line Switcher IC is a highly integrated AC-DC power conversion IC designed for compact and energy-efficient switched-mode power supplies (SMPS). Belonging to the TOPSwitch™-HX family, this device integrates a high-voltage power MOSFET, PWM controller, oscillator, and multiple protection features into a single component.

The TOP257YN significantly reduces external component count, simplifying power supply design while improving efficiency and reliability. It supports a wide AC input voltage range and delivers stable, regulated output, making it ideal for industrial equipment, adapters, chargers, LED drivers, and home appliances.

Built-in safety protections such as thermal shutdown, over-current limiting, auto-restart, and line over-voltage protection ensure secure and long-term operation. The “YN” version comes in a TO-220 package, suitable for higher power applications with efficient heat dissipation.

Key Features :

• Integrated high-voltage power MOSFET

• PWM control with precise regulation

• Wide input voltage range

• Over-temperature protection

• Over-current and short-circuit protection

• Auto-restart feature

• Line over-voltage protection

• TO-220 (YN) package for better thermal performance