Description
The CS51221 fixed frequency feed forward voltage mode PWM controller contains all of the features necessary for basic voltage mode operation. This PWM controller has been optimized for high frequency primary side control operation. In addition, this device includes such features as: Soft Start, accurate duty cycle limit control, less than 50µA startup current, over and under voltage protection, and bidirectional synchronization. The CS51221 is available in 16 lead PDIP and SO narrow surface mount packages.

Features
■ 1MHz Frequency Capability
■ Fixed Frequency Voltage Mode Operation, with Feed Forward
■ Thermal Shutdown
■ Under Voltage Lock-out
■ Accurate Programmable Max Duty Cycle Limit
■ 1A Sink/Source Gate Drive
■ Programmable Pulse by Pulse Over Current Protection
■ Leading Edge Current Sense Blanking
■ 75ns Shutdown Propagation Delay
■ Programmable Soft Start
■ Under Voltage Protection
■ Over Voltage Protection with Programmable Hysteresis
■ Bidirectional Synchronization
■ 25ns GATE Rise and Fall Time (1nF load)
■ 3.3V 3% Reference Voltage Output