This part is a kind of semiconductor called LM2596.

Function of this product has SIMPLE SWITCHER Power Converter 150 kHz 3A Step-Down Voltage Regulator.

Manufacturers : National Semiconductor

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LM2596 SIMPLE SWITCHER Power Converter 150 kHz 3A Step-Down Voltage Regulator December 1997 LM2596 SIMPLE SWITCHER ® Power Converter 150 kHz 3A Step-Down Voltage Regulator General Description The LM2596 series of regulators are monolithic integrated circuits that provide all the active functions for a step-down (buck) switching regulator, capable of driving a 3A load with excellent line and load regulation. These devices are available in fixed output voltages of 3.3V, 5V, 12V, and an adjustable output version. Requiring a minimum number of external components, these regulators are simple to use and include internal frequency compensation†, and a fixed-frequency oscillator. The LM2596 series operates at a switching frequency of 150 kHz thus allowing smaller sized filter components than [ ... ]

LM2596 PDF Datasheet Download