ADMP401 startup

Document created by analog-archivist Employee on Feb 23, 2016Last modified by analog-archivist Employee on Feb 23, 2016
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One of our customer, RADE, is using the ADMP401. They are watching a delay of
30 ms., between the power on of the system and the signal presence in the
output. You can see the picture attached.

In the datasheet there isn´t any information about this point, and they need to
know if this is the typical behavior, and if this could be reduced.


Yes, this is normal behavior. After power is applied to the microphone, the
internal charge pump that generates the bias voltage has some start up time
that occurs before the microphone will output a signal. This is what your
customer is seeing. I hope that this isn’t an issue for their system design.
For most customers, this short start-up time is not an issue.