The FSQ110 consists of an integrated, current-mode, Pulse Width Modulator (PWM) and an avalanche-rugged 650V SenseFET. It is specifically designed for highperformance off-line Switch-Mode Power Supplies (SMPS) with minimal external components. The integrated PWM controller features include: a fixedfrequency generating oscillator, Under-Voltage Lockout (UVLO) protection, Leading-Edge Blanking (LEB), an optimized gate turn-on/ turn-off driver, Thermal Shutdown (TSD) protection, and temperaturecompensated precision current sources for loop compensation and fault protection circuitry. Compared to a discrete MOSFET and controller or RCC switching converter solution, the FSQ110 reduces total component count, design size, and weight while increasing efficiency, productivity, and system reliability. These devices provide a basic platform that is well suited for the design of cost-effective flyback converters.