REF200: Accuracy on current sensor

Neil DSouza

Part Number: REF200

I'm using a TI recommended circuit with the REF200 to measure a PT100. The typical accuracy on the matched current sources is 0.25% and the match is 0.25%, but the maximum values of each are 1%. Can someone at TI tell me what the distribution is on the accuracy? How typical is 0.25% accuracy?

over 5 years ago

0 Marcoo Z over 5 years ago

TI__Mastermind 19370 points

Hi Niel,

If you don't mind asking, what is the TI recommended circuit that is using the REF200?

For the distribution, you can assume it is a normal distribution but the actual distribution is confidential and cannot be disclosed.

-Marcoo

0 Neil DSouza over 5 years ago in reply to Marcoo Z

Prodigy 20 points

Hi,

This is the circuit I'm using: www.ti.com/.../tidu969.pdf

Assuming a normal distribution would be okay, but I'd need to know what the variance is on the error. Otherwise I don't think we can use these chips in our design as it would force us to calibrate every board.

Regards

Neil

0 Marcoo Z over 5 years ago in reply to Neil DSouza

TI__Mastermind 19370 points

Hi Neil,

Thank you for the circuit diagram.

It is company policy that we cannot disclose this information so I cannot help you any further with this request.

If 1% initial accuracy error is too much, there is other ways of creating a constant current source for this type of circuit. The following documentation has examples of using voltage references to create a constant current source that can be more accurate.
www.ti.com/.../snoa838.pdf

-Marcoo

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REF200: Accuracy on current sensor