User's Manual

LZT 123 1834 51
With the module powered normally, ON/OFF is pulled-up to VCC potential. In order
to power down the module, ON/OFF is pulled to ground. Once ON/OFF has been held
low for at least 125ms the shut-down procedure begins. Although ON/OFF can be
held low for longer, it will delay completion of the shut-down event. If the module is
registered on a GSM network, the de-registration process will complete; this may last
between 3 to 30 seconds. The power latch (PWR_KEEP) is released and approximately
70ms later the LDO outputs fall.
For module variants where VREF is an output, the absence of VREF is a useful
indicator that the network de-registration and shut-down is complete. Once VREF is
no longer present, the application can safely remove VCC.
the RTC can continue to operate even though VCC is removed, provided
that a sufficiently charged backup device is connected to the VRTC.
Refer to section 5.18.1 for details.
The relevant characteristics of the ON/OFF Power control interface are shown in the
table below.
Parameter Conditions Min Typ Max Unit
Input low (0V), VCC = 3.6V -60 -25 -12
µA
Input current
Input high (VCC), VCC = 3.6V 0 1
µA
NOTE