I am working on a new hardware design utilizing the Analog Devices
>ADN8831 TEC controller.
>
>We are having a problem with the ADN8831 going into cooling mode. We
>are monitoring the VTEC output of the device and out2. When we
>transition from 88.0 C to 44.0 C degrees, the VTEC pin does not go
>above 1.25 volts (VTEC above 1.25 indicates the ADN8831 is in cooling
>mode) but out2 goes less than 1.5. According to the figure 21 of
>ADN8831 data sheet, when out2 goes below 1.5 volts, its should go into
>cooling. We never reach the 44.0 C temperature.
>
>In our design, PVDD = AVDD = 3.3 volts.
>
>Heating seems to work as we expect.
>
>Has anyone powered this device at 3.3 volts, the datasheet indicates
>it should work down to 3.0 volts?
>
>Any ideas why it will not cool?
>
Have you tried contacting ADI's Applications Group about this? I know a few of these guys (they work upstairs from me) and they're usually pretty knowledgeable.
Thanks,
>Alex