Variable Power Supply 1.2 to 55 Volts 3 Ampere

I was looking to get a 12 volts DC-DC converter for my 7 " LCD as i don't want to power it directly from battery.

Here is a nice Switching mode Regulator LM2576 series IC from National Semiconductor, I found it is such a good regulator according to DS:

The LM2576 series of regulators are monolithic integrated circuits that provide all the active functions for a step-down (buck) switching regulator, capable of driving 3A load with excellent line and load regulation. These devices are available in fixed output voltages of 3.3V, 5V, 12V, 15V, and an adjustable output version.

here is the schematics:
 

Finished Circuit :

In local market i could not find LM2576 (12V), only Adj. version is available so i decided to go with that one. I adjusted R2 preset for 12 volts as per my need.

Features
- 3.3V, 5V, 12V, 15V, and adjustable output versions
- Adjustable version output voltage range,
- 1.23V to 37V (57V for HV version) ±4% max over line and load conditions
- Guaranteed 3A output current
- Wide input voltage range, 40V up to 60V for
- HV version
- Requires only 4 external components
- 52 kHz fixed frequency internal oscillator
- TTL shutdown capability, low power standby mode
- High efficiency
- Uses readily available standard inductors
- Thermal shutdown and current limit protection

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