User's Manual

LISA-U1/LISA-H1 series - System Integration Manual
3G.G2-HW-10002-2 Advance Information System description
Page 28 of 116
ACTIVE MODE
20-22 mA 20-22 mA
~150 mA
RX+DSP
Enabled
20-22 mA
~150 mA
2G case: 0.47-2.12 s
3G case: 0.64-5.12 s
Paging period
Time [s]
Current [mA]
150
100
50
0
Time [ms]
Current [mA]
150
100
50
0
Figure 14: Description of the VCC current consumption profile versus time when power saving is disabled: active-mode is
always held, and the receiver and the DSP are periodically activated to monitor the paging channel for paging block reception
1.5.4 RTC Supply (V_BCKP)
The V_BCKP pin connects the supply for the Real Time Clock (RTC) and Power On / Reset internal logic. This
supply domain is internally generated by a linear regulator integrated in the Power Management Unit. The
output of this linear regulator is always enabled when the main voltage supply provided to the module through
VCC is within the valid operating range, with the module switched-off or powered-on.
Name
Description
Remarks
V_BCKP
Real Time Clock supply
V_BCKP = 2.3 V (typical) generated by the module to supply
Real Time Clock when VCC supply voltage is within valid
operating range.
Table 7: Real Time Clock supply pin
The V_BCKP pin ESD rating is 1 kV (contact discharge). A higher protection level could be required if the
line is externally accessible on the application board. A higher protection level can be achieved by
mounting an ESD protection (e.g. EPCOS CA05P4S14THSG varistor array) on the line connected to this
pin.
The RTC provides the time reference (date and time) of the module, also in power off mode, when the V_BCKP
voltage is within its valid range (specified in u-blox LISA-U1/LISA-H1 series Data Sheet [1]). The RTC timing is