LM5117: Zero input offset: how does it affect CM pin output

Sourabh Renavikar

Part Number: LM5117

Dear All,

I'd like to understand how to interpret this specification when it comes to calculating voltage on CM pin at a given load current.

What I have interpreted is that if offset is 25mV, then with 4 mOhm current sense resistor, I may read no voltage on CM pin until minimum load current is 357mA. (25mV / 4mOhm * 17.5). Is this understanding correct?

Also, is this offset bidirectional?

Regards,

Sourabh

over 6 years ago

0 David Baba over 6 years ago

TI__Mastermind 26450 points

We are looking into this and will respond shortly.

Thanks.

0 David Baba over 6 years ago

TI__Mastermind 26450 points

Hello Sourabh,

Please see answers below to your questions.

1. Is it voltage measured at IMON pin with zero signal across shunt resistor? Or
ans: The voltage is the offset measured at the CM pin to Agnd.
2. Is it input referred?
ans: No
3. Also typical value is 25mV, does it mean +/-25mV offset or +/-12.5mV ?
ans :The Specification is as stated, that is: +25mV (at room temp) to +120mV (Max over full temp range).

Hope this helps?

David.

0 David Baba over 6 years ago in reply to David Baba

TI__Mastermind 26450 points

Hello Sourabh,

Please can you detail what further information you need?

Thanks.

David.

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LM5117: Zero input offset: how does it affect CM pin output