[88] WDT: Increased current consumption when configured to pause in System ON idle

This anomaly applies to IC Rev. Rev 2, build codes QFAA-E00, CIAA-E00, QFAB-E00.

It was inherited from the previous IC revision Rev 1.

Symptoms

Using the mode where watchdog is paused in CPU Idle, the current consumption jumps from 3 µA to 400 µA.

Conditions

When we enable WDT with the CONFIG option to pause when CPU sleeps:

NRF_WDT->CONFIG = (WDT_CONFIG_SLEEP_Pause<<WDT_CONFIG_SLEEP_Pos);

Consequences

Reduced battery life.

Workaround

Do not enter System ON IDLE within 125 µs after reloading the watchdog.