GSENSOR_3V3 voltage drop

Werner Almesberger werner at openmoko.org
Mon Aug 24 13:56:15 CEST 2009


Christoph Mair wrote:
> The voltage is now between 3.32V and 3.44V which seems to be ok,

It seems a little high for a nominal 3.3 V, but it's within range.

By the way, the accelerometers should be okay at a lower voltage:
the chip has a valid supply voltage range of 2.16 to 3.6 V, with
2.5 V being the typical voltage. We couldn't go as low as 2.5 V,
because we'd then violate the VDD_IO+0.3 V limit on the I/O pins,
but a voltage as low as 3.0 V would be acceptable.

The 2.8 V you measured initially would be too low, causing current
to leak through the clamp diodes on the I/O lines during normal
operation.

If we're now operating at a hopefully constant ~3.3 V, it would be
interesting to see if this has an effect on the accuracy of
acceleration measurements. I wouldn't be surprised if it did.

- Werner



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