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 50A startup current, over and undervoltage protection, and bidirectional synchronization. The CS51221 is available in a 16 lead SOIC narrow surface mount package.

Features

• 1.0 MHz Frequency Capability

• Fixed Frequency Voltage Mode Operation, with Feed Forward

• Thermal Shutdown

• Undervoltage Lock−Out

• Accurate Programmable Max Duty Cycle Limit

• 1.0 A Sink/Source Gate Drive

• Programmable Pulse−By−Pulse Overcurrent Protection

• Leading Edge Current Sense Blanking

• 75 ns Shutdown Propagation Delay

• Programmable Soft−Start

• Undervoltage Protection

• Overvoltage Protection with Programmable Hysteresis

• Bidirectional Synchronization

• 25 ns GATE Rise and Fall Time (1.0 nF Load)

• 3.3 V 3 Reference Voltage Output

• Pb−Free Packages are Available*