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BQ76907-Q1: Current Gain Variation

Max Nemer
Prodigy 50 points
Part Number: BQ76907-Q1
Other Parts Discussed in Thread: BQ76907

Hello All, 

I am trying to calculate a full error stack up for the bq76907 current meaurement chain. I am curious if the figure in the Specifications table of B_CM_GAIN / B_CM_GAIN Drift includes the effect of VREF2 already? Or does the gain / gain drift only account for the variabillity of the G1=5 amplifier? 

image.png

this can be seen in the equation: 

Amps / LSB = {VREF2 / ( G1 * 2^23)} / (G2 / 8192)

Where G1 = 5 and G2 = 32

  • 0
    Prodigy 50 points

    Also, are these values for gain using the 1.227V Reference? The Nominal case doesn't work out to 5 exactly, as I would expect.

    Just like the 7.52uV/count issue we found earlier, it seems like these values may be expecting a different (original?) reference voltage (possibly 1.232V? ) 

    -Max