SWRZ121A February 2022 – March 2022 CC2651R3
Elevated power-on-reset (POR) threshold voltage at low temperatures
Revision B
When powering up the device from 0V at temperatures < 0°C, the power-on-reset (POR) circuit may not release reset until VDDS reaches 2.3V, and not at 1.8V as intended. After POR has released the reset, an affected device will continue to operate at voltages down to 1.8V.
This behavior is only observed during power up and does not occur when the device is subjected to an external pin reset, wake-up from shutdown, or watchdog reset.
The occurrence is rare and is only observed on very few devices.
Workaround 1: Power-up the devices at VDDS > 2.3V when operating at temperatures below 0°C.
or
Workaround 2: Power-up the device at VDDS < 2.3V, trigger the Reset-pin from a host MCU or external circuitry.
In addition, when operating the device in external regulator mode, workaround 2 must be implemented. Please note that VDDS must not exceed 1.95V in external regulator mode. This is applicable only to devices that have external regulator mode support.