Description
Each product in the FSDx321 (x for H, L) family consists of an
integrated Pulse Width Modulator (PWM) and SENSEFET, and is
specifically designed for high performance offline Switch Mode
Power Supplies (SMPS) with minimal external components. Both
devices are integrated high voltage power switching regulators which
combine an avalanche rugged SENSEFET® with a current 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),
an optimized gate turn−on/turn−off driver, Thermal Shut Down (TSD)
protection, Abnormal Over Current Protection (AOCP) and
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 FSDx321 devices reduce total component count, design
size, weight while increasing efficiency, productivity and system
reliability. Both devices provide a basic platform that is well suited for
the design of cost−effective flyback converters

Features
• Internal Avalanche Rugged SENSEFET
• Consumes only 0.65 W at 240 VAC & 0.3 W Load with Advanced
Burst−Mode Operation
• Frequency Modulation for EMI Reduction
• Precision Fixed Operating Frequency
• Internal Start−up Circuit
• Pulse−by−Pulse Current Limiting
• Abnormal Over Current Protection (AOCP)
• Over Voltage Protection (OVP)
• Over Load Protection (OLP)
• Internal Thermal Shutdown Function (TSD)
• Auto−Restart Mode
• Under Voltage Lockout (UVLO)
• Low Operating Current (max. 3 mA)
• Adjustable Peak Current Limit
• Built−in Soft Start

Applications
• SMPS for STB, Low Cost DVD Player
• Auxiliary Power for PC
• Adapter & Charger