Refer to the PDF data sheet for device specific package drawings
The module enters a brownout condition whenever the input voltage dips below VBROWNOUT (see Figure 8-4 and Figure 8-5). This condition must be considered during design of the power supply routing, especially if operating from a battery. High-current operations, such as a TX packet or any external activity (not necessarily related directly to networking) can cause a drop in the supply voltage, potentially triggering a brownout. The resistance includes the internal resistance of the battery, contact resistance of the battery holder (four contacts for a 2× AA battery), and the wiring and PCB routing resistance.
When the module is in HIBERNATE state, brownout is not detected. Only blackout is in effect during HIBERNATE state.
In the brownout condition, all sections of the device shut down within the module except for the Hibernate block (including the 32-kHz RTC clock), which remains on. The current in this state can reach approximately 400 µA. The blackout condition is equivalent to a hardware reset event in which all states within the module are lost. Vbrownout = 2.1 V and Vblackout = 1.67 V
Table 8-1 lists the brownout and blackout voltage levels.