Output Voltage Noise Measuring

Hi ChrisHuang,

To measure the AD8476 RMS output noise in the 0.1Hz to 10Hz band, similar to Figure 35 plot, you'd need to put together a sharp 0.1Hz to 10Hz passband filter. I'd think just using a source meter would not be able to allow you to compare the readings against the datasheet 6uV RMS typical value.

Sounds like you're seeing variation in output noise between different devices. If you have access to an oscilloscope or spectrum analyzer, you'd be better able to narrow down the cause of the different noise readings by probing the output and looking for differences between units. Sometimes instability of the circuit could look like a difference in noise reading.

Regards,

Hooman

The resolution of the oscilloscope in lab is too bad, and I don't have a appropriate probe to use.

Because of the noise or functionality of source meter, I put input to GND, both +IN and -IN. The output voltage should be under the differential offset voltage 500µV.

The result is,  output differential voltage is 67µV, another one is 139µV, both of them are under 500µV. But the maximum value minus minimum value, one is 3µV, another one is 10µV.

I send the component to ADI throuht local distributor for failure analysis report one month ago, but the autoamtic test quipment (ATE) testing results showed that the component is passing in all test include functionality and error tests. Can I ask for another test? What kind of test?