On the ( custom-made ) board I'm debugging, the PMU ( AD5522 ) is powered with:
AVDD = +10V
AVSS = -5V
VREF = +2.5V
I know this AVDD/AVSS combination violates the PMU DataSheet.
Further I'm using:
OFFSET-DAC = 0x0000
Current Gain = 5
Measout Gain = 0.2
In the FVMI mode, I get the expected/desired behaviour in the lower and mid parts of the nominal current ranges.
However, for both internal and external sense-resistors, with consistency the voltage at MEASOUTx
stops increasing when the DUT-current reaches approximately 77% of the nominal maximum value.
At this point Vsense = Rsense x Idut = 0.70V, this is illustrated in the table below ( The table actually shows the true Idut at onset of the "MEASOUT clipping").
Image may be NSFW.
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The plot below shows the results from a series taken with an external Rsense = 50 ohm.
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Can anyone advice me a better PMU setting/configuration that could give me current measure capability
also in the higher part of the nominal range ? ( Given the erroneous AVDD/AVSS combination I'm already aware of).
Thanks
Trygve
