Voltage drop in LM2931AZ-5.

[amayilsamy]

I'm using the Voltage regulator LM2391.

All are three different circuit. And maximum Load current is 40 mA.

First regulator output voltage is 4.85 V

Second regulator voltage regulator 4.91 V

Third regulator voltage regulator 5.01 V

Why is this different in LM2931AZ-5..

View attachment LM2931.bmp

 

[HMS1021]

The differences are mainly variation from part to part with a very small part of the difference being temperature, and measurement accuracy. The LM2931AZ-5 data sheet says the output voltage range is 4.75V to 5.25V when measure at 10ma. Your 3 parts meet the specification with margin. There are LDOs with tighter output levels.

 

[amayilsamy]

Its . Other voltage regulators working 5.01 V like LM7805. I'm using this for ADC that what the problem.

How to manage this?

 

[rahdirs]

I don't understand what you're problem is,as explained by @HMS1021, your o/p voltage is within the margin.

Are you saying you want to have o/p of 3 voltage regulators that you have at 5.01 Vso that your ADC sees no margin ???.Can you explain a bit on how you're trying to use ADC ???