TPS51200: What is the total tolerance on Vout w.r.t Refin

Praveen GD

Guru 57737 points

Part Number: TPS51200

Hi Team,

What is the total tolerance on Vout w.r.t Refin?

REFIN to Refout tolerance is 15mV & Vout to Refout tolerance is listed as 25mV,

So, is the total tolerance the RSS (Root Sum of Squares) sum of these two errors or direct addition of them?

Reards,

Praveen

over 7 years ago

0 Qian Chen over 7 years ago

TI__Mastermind 24075 points

HI Praveen,

During TPS51200 operation, Vout follows Refout, and Refout follows Refin. This actual tolerance is smaller because Refout current is very small (several uA) in DDR application.
Refout to Refin tolerence is 12mV. Vout to Refout tolerance is 25mV.

So therotically the total tolerance is 12mV+25mV=37mV, which is not likely to happen in real case.

Thanks
Qian

0 Praveen GD over 7 years ago in reply to Qian Chen

TI__Guru 57737 points

Hi Qian,

Since, Refout to Refin tolerance and Vout to Refout are uncorrelated errors, shouldn't we do an Root Sum of Squares to find out the total tolerance ?

Regards,
Praveen GD

0 Qian Chen over 7 years ago in reply to Praveen GD

TI__Mastermind 24075 points

Hi Praveen,

You can do that. It is a practical method to estimate the total tolerance.

What I said is theoretically.

Thanks

Qian

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TPS51200: What is the total tolerance on Vout w.r.t Refin