Power Off - Fibocom NL668-LA Series Hardware Manual

Figure 5-3 shows power on timing.
Note:
Before pull down PWRKEY pin, the Voltage of VBAT must be stable, recommended time
interval between VBAT enable and pull down PWRKEY pin at least 30ms.

5.1.1.2 Power Off

The module supports three power off methods as table 5-2.
Reproduction forbidden without Fibocom Wireless Inc. written authorization - All Rights Reserved.
FIBOCOM NL668-LA Series Hardware Guide
Figure 5-2 Button switch power on reference circuit
Figure 5-3 Power on timing
Page 26 of 61