SC4905A

POWER MANAGEMENT Description The SC4905A/B is a 10 pin BICMOS primary side voltage mode controller for use in Isolated DC-DC and off-line switching power supplies. It is a highly integrated solution, requiring few external components. The device features a high speed oscillator with integrated feed forward compensation, accurately programmable maximum duty cycle, voltage mode of operation, line voltage monitoring, supply UVLO, low start up current, low voltage current limit threshold and user accessible reference. www.DataSheet4U.com The SC4905A/B device operates at a fixed frequency, highly desirable for Telecom applications. Features a separate SYNC pin which simplifies synchronization to an external clock. Feeding the oscillator of one device to the SYNC of another forces biphase operation (180 degrees apart) which reduces input ripple and filter size. The SC4905A has a turn-on threshold of 4.5V and the SC4905B has a turn-on threshold of about 12 volts. These devices are available in the 10 lead MSOP package. High Performance Voltage Mode PWM Controller PRELIMINARY Features K Operation to 1MHz K Accurate programmable maximum duty cycle K Integrated oscillator/voltage feed forward K K K K K K K K SC4905A/B compensation Line voltage monitoring External frequency synchronization Bi-phase mode of operation for ripple reduction Under 100µA start-up current Accessible reference voltage VDD undervoltage lockout -40°C to 105°C operating temperature 10 lead MSOP package Applica...