Dropout voltage of LM350K STEEL/NOPB @ 3A out out current

Hello Madiwalesh,

The LM350 Minimum Operating Vin to ensure 3A output = Vout+3V = 5.0V+3.0V = 8.0V

That will cause 6W (3A x 3V) to be dissipated in the K (TO-3 / NDS) package. A heat sink will be needed.

I do suggest that you consider a Buck SMPS as it will give superior efficiency (less heat).

If a linear regulator is required, here are some options with lower Vin to Vout requirements:

LM1084 - 5A Low Dropout Positive Regulators

www.ti.com/.../LM1084

LM1085 - 3A Low Dropout Positive Regulators

www.ti.com/.../LM1085

LP3856 - 3A Fast Ultra Low Dropout Linear Regulator

www.ti.com/.../LP3856

LP3873 - 3A Fast Ultra Low Dropout Linear Regulator

www.ti.com/.../LP3873

Thanks for the reply Donald Jones   

Thanks for the suggestion. SUGGESTION you have made is the cause this question rose to us. The constraint  to us is we already have a board made with LM350K STEEL/NOPB  (TO-3 STEEL) Metal Can Package, with input voltage 9.0 V. We are in plan to insert a PCB with SMPS (BUCK) & reduce 9.0 v to minimum possible, before supplying 9.0 V to LM350K STEEL/NOPB. since the Board already present cannot be changed can i get any device with lesser drop out but (TO-3 STEEL) Metal Can Package

can i get a graph of Dropout voltage or (minimum required) vs current driven for LM350K STEEL/NOPB.??

" ... can i get a graph of Dropout voltage ..."

Yes, from the LM350 datasheet ...

can i get any device with lesser drop out but (TO-3 STEEL) Metal Can Package

List of every TI regulator in the TO-3 package that can deliver at least 3A:

Looks like the LM323 is just a bit lower.