CQ1565RT PDF – FSCQ1565RT – Green Mode Power Switch

Part Number: CQ1565RT, FSCQ1565RT

Function: Green Mode Fairchild Power Switch

Package: TO-220F-5L Type

Manufacturer: Fairchild Semiconductor

Images:CQ1565RT pinout datasheet


CQ1565RT is Green Mode Fairchild Power Switch.

“Green Mode” Fairchild Power Switch is a term associated with a family of integrated circuits (ICs) manufactured by Fairchild Semiconductor (now part of ON Semiconductor). These ICs are commonly used in switch-mode power supplies and are designed to provide high efficiency and low standby power consumption, hence the “Green Mode” designation.

The Green Mode Fairchild Power Switches are used in a variety of power supply applications, such as adapters, chargers, and other devices that require efficient power conversion. They feature advanced power management techniques to reduce power losses and achieve higher efficiency levels, which is beneficial for energy-saving and environmentally-friendly designs.

In general, a Quasi-Resonant Converter (QRC) shows lower EMI and higher power conversion efficiency compared to conventional hard-switched converter with a fixed switching frequency. Therefore, a QRC is well suited for noisesensitive applications, such as color TV and audio. Each product in the FSCQ-Series contains an integrated Pulse Width Modulation (PWM) controller and a SenseFET, and is specifically designed for quasi-resonant off-line Switch Mode Power Supplies (SMPS) with minimal external components. The PWM controller includes an 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


• Optimized for Quasi-Resonant Converter (QRC)

• Advanced Burst-Mode Operation for under 1W Standby Power Consumption

• Pulse-by-Pulse Current Limit

• 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)

• Internal High Voltage SenseFET

• Built-in Soft Start (20ms)

• Extended Quasi-Resonant Switching


CQ1565RT pdf fairchild

1. Drain: High voltage power SenseFET drain connection.

2. GND: This pin is the control ground and the SenseFET source.

3. Vcc: This pin is the positive supply input. This pin provides internal operating
current for both start-up and steady-state operation.

4. Vfb: This pin is internally connected to the inverting input of the PWM comparator. The collector of an opto-coupler is typically tied to this pin. For stable operation, a capacitor should be placed between this pin and GND. If the voltage of this pin reaches 7.5V, the over load protection triggers, which results in the FPS shutting down.

5. Sync: This pin is internally connected to the sync detect comparator for quasiresonant switching. In normal quasi-resonant operation, the threshold of the sync comparator is 4.6V/2.6V. Whereas, the sync threshold is changed to 3.0V/1.8V in an extended quasi-resonant operation.




• Audio Amplifier

CQ1565RT PDF Datasheet