This part is a kind of semiconductor called UC3843B.

Function of this product has (UC3842B / UC3843B) HIGH PERFORMANCE CURRENT MODE CONTROLLERS.

Manufacturers : Motorola

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Order this document by UC3842B/D UC3842B, 43B UC2842B, 43B High Performance Current Mode Controllers The UC3842B, UC3843B series are high performance fixed frequency current mode controllers. They are specifically designed for Off–Line and dc–to–dc converter applications offering the designer a cost–effective solution with minimal external components. These integrated circuits feature a trimmed oscillator for precise duty cycle control, a temperature compensated reference, high gain error amplifier, current sensing comparator, and a high current totem pole output ideally suited for driving a power MOSFET. Also included are protective features consisting of input and reference undervoltage lockouts each with hysteresis, cycle–by–cycle current limiting, prog [ ... ]

UC3843B PDF Datasheet Download