CQ0765RT PDF – Fairchild Power Switch – FSCQ0765RT

Fairchild Power Switches were commonly used in switch-mode power supplies (SMPS) to regulate and control the power flow efficiently. They integrated various features such as overvoltage protection, overcurrent protection, thermal shutdown, and other control mechanisms to ensure the safe and reliable operation of power supply systems.

This post explains for the semiconductor FSCQ0765RT.

The Part Number is CQ0765RT.

The function of this semiconductor is Green Mode Fairchild Power Switch.

The package is TO-220F-5L Type

Manufacturer: Fairchild Semiconductor

Preview images :CQ0765RT pdf switch


CQ0765RT is Green Mode Fairchild Power Switch (FPSTM) for Quasi-Resonant Switching Converter.

In general, Quasi-Resonant Converter (QRC) shows lower EMI and higher power conversion efficiency compared to the conventional hard switched converter with a fixed switching frequency. Therefore, it is well suited for applications that are sensitive to the noise, such as color TV and audio. The FSCQ0765RT is an integrated Pulse Width Modulation (PWM) controller and Sense FET specifically designed for
Quasi-resonant off-line Switch Mode Power Supplies (SMPS) with minimal external components.

The PWM controller includes integrated fixed frequency oscillator, under voltage lockout, leading edge blanking (LEB), optimized gate driver, internal soft start, temperature compensated precise current sources for a loop compensation and self protection circuitry. Compared with discrete MOSFET and PWM controller solution, it can reduce total cost, component count, size and weight simultaneously increasing efficiency, productivity, and system reliability.


• Optimized for Quasi-Resonant Converter (QRC)

• Advanced Burst-Mode operation for under 1 W standby power consumption

• Pulse by Pulse Current Limit (5A)

• Over load protection (OLP) – Auto restart

• Over voltage protection (OVP) – Auto restart

• Abnormal Over Current Protection (AOCP) – Latch

• Internal Thermal Shutdown (TSD) – Latch

• Under Voltage Lock Out (UVLO) with hysteresis

• Low Startup Current (typical : 25uA)

• Low Operating Current (typical : 4mA)

• Internal High Voltage SenseFET

• Built-in Soft Start (20ms)

• Extended Quasi-resonant Switching for Wide Load Range

Block Diagram:

CQ0765RT datasheet pinout



• DVD Receiver

• Audio Power Supply

CQ0765RT PDF Datasheet