nrf52 Power consumption intermittently high

[eq]

We have recently migrated from a custom board based on the nrf51 to a new board with the nrf52832. Our nrf51 board used to run at 6-8 uA when it was just sitting there advertising. The new board is running at about 34 uA, but sometimes inexplicably starts consuming 500 uA after radio communications from the iPhone central. This behavior is very intermittent.

We are using the SAADC in Scan mode to periodically measure battery voltage and temperature via a thermistor, both using voltage dividers.

I am on SDK 12.2 using the S132 Soft Device. I can't seem to figure out why the board sometimes starts consuming 500uA. It is very intermittent. Have you all seem the nrf52 get into a state like this? If so what can cause it?

Also, is 6 to 8 uA achievable with the nrf52? BTW, for the AtoD conversions I am enabling the SAADC prior to measurement, and then turning it off after per some recommendations on this forum to conserve power.

Thanks for your help.

[John]

@eq - We had a similar issue migrating from the 51 to the 52. Here are a couple of other things I would check: 1) If the HW is set up for DC-DC converter, be sure to enable it. 2) If you are using the TWI look at PAN-89 in the errata 3) There was a note about when clearing Events, read them back to make sure the clear is flushed to RAM before moving on. 4) Make sure to use sd_app_event_wait when idling rather than __WFE