TPS929120-Q1: Vref min. and max. value

PYTsai

Genius 11505 points

Part Number: TPS929120-Q1

Can you provide Vref min. and max. value ?

Datasheet only list typical value.

over 3 years ago

0 Ben Waal over 3 years ago

TI__Intellectual 1285 points

Hi PY,

Is there any requirement on the accuracy of V(REF) for your application?

0 PYTsai over 3 years ago in reply to Ben Waal

TI__Genius 11505 points

Hi Ben,

No requirement on the accuracy. Customer would like to use this information to calulate the worst case current drifft

0 Ben Waal over 3 years ago in reply to PYTsai

TI__Intellectual 1285 points

Hi PY,

Is that the worst case current drift for the output channels? How does the customer plan to calculate this?

I can provide some estimate, but there is no guarantee as it is not specified in the datasheet.

0 PYTsai over 3 years ago in reply to Ben Waal

TI__Genius 11505 points

Hi Ben

Below are example that customer may consider

Ex: as below circuit, if the resistor R66 got -3% error

ILED: 1.235 / (8.45*0.97) * 512 = 77.145mA. In this case they need to know the Vref max value to calculate will the final current will go outside the recommend ranage.

0 Ben Waal over 3 years ago in reply to PYTsai

TI__Intellectual 1285 points

Hi PY,

To calculate the worst case accuracy, the ΔI(out_d2d) spec in the datasheet should be used. This already includes the inaccuracies of V(REF), K(REF), and channel output current DAC. The only factor not included in this spec is the reference resistor accuracy. The total accuracy can then be calculated by the square root of the squared sum of both accuracies, e.g.:

√((3%)²+(5%)²)=5.8%

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TPS929120-Q1: Vref min. and max. value