The FSD200 and FSD210 are integrated Pulse Width Modulators (PWM) and Sense FETs specially designed for high performance off-line Switch Mode Power Supplies (SMPS) with minimal external components. Both devices are monolithic high voltage power switching regulators which combine an LDMOS Sense FET with a voltage mode PWM control block. The integrated PWM controller features include: a fixed oscillator with frequency modulation for reduced EMI, Under Voltage Lock Out (UVLO) protection, Leading Edge Blanking (LEB), optimized gate turn-on/turnoff driver, thermal shut down protection (TSD), temperature compensated precision current sources for loop compensation and fault protection circuitry. When compared to a discrete MOSFET and controller or RCC switching converter solution, the FSD200 and FSD210 reduce total component count, design size, weight and at the same time increase efficiency, productivity, and system reliability. The FSD200 eliminates the need for an auxiliary bias winding at a small cost of increased supply power. Both devices are a basic platform well suited for cost effective designs of flyback converters.