User's Manual

SARA-G3 and SARA-U2 series - System Integration Manual
UBX-13000995 - R08 Objective Specification System description
Page 20 of 188
1.5 Supply interfaces
1.5.1 Module supply input (VCC)
The modules must be supplied via the three VCC pins that represent the module power supply input.
The VCC pins are internally connected to the RF power amplifier and to the integrated Power Management Unit:
all supply voltages needed by the module are generated from the VCC supply by integrated voltage regulators,
including V_BCKP Real Time Clock supply, V_INT digital interfaces supply and VSIM SIM card supply.
During operation, the current drawn by the SARA-G3 and SARA-U2 series modules through the VCC pins can
vary by several orders of magnitude. This ranges from the high peak of current consumption during GSM
transmitting bursts at maximum power level in connected-mode (as described in section 1.5.1.2), to the low
current consumption during low power idle-mode with power saving enabled (as described in section 1.5.1.4).
1.5.1.1 VCC supply requirements
Table 7 summarizes the requirements for the VCC module supply. See section 2.2.1 for all the suggestions to
properly design a VCC supply circuit compliant to the requirements listed in Table 7.
VCC supply circuit affects the RF compliance of the device integrating SARA-G3 and SARA-U2
series modules with applicable required certification schemes as well as antenna circuit design.
Compliance is guaranteed if the VCC requirements summarized in the Table 7 are fulfilled.
For the additional specific requirement for SARA-G350 ATEX modules integration in potentially explosive
atmospheres applications, see section 2.14.
Item
Requirement
Remark
VCC nominal voltage
Within VCC normal operating range:
3.35 V min. / 4.50 V max for SARA-G3 series
3.30 V min. / 4.40 V max for SARA-U2 series
The module cannot be switched on if VCC voltage value
is below the normal operating range minimum limit.
Ensure that the input voltage at VCC pins is above the
minimum limit of the normal operating range for at least
more than 3 s after the module switch-on.
VCC voltage during
normal operation
Within VCC extended operating range:
3.00 V min. / 4.50 V max for SARA-G3 series
3.10 V min. / 4.50 V max for SARA-U2 series
The module may switch off when VCC voltage drops
below the extended operating range minimum limit.
Operation above extended operating range limit is not
recommended and may affect device reliability.
VCC average current
Considerably withstand maximum average current
consumption value in connected-mode conditions
specified in the SARA-G3 series Data Sheet [1] and in
the SARA-U2 series Data Sheet [2].
The maximum average current consumption can be
greater than the specified value according to the actual
antenna mismatching, temperature and VCC voltage.
See 1.5.1.2, 1.5.1.3 for connected-mode current profiles.
VCC peak current
Withstand the maximum peak current consumption
specified in the SARA-G3 series Data Sheet [1] and in
the SARA-U2 series Data Sheet [2].
The specified maximum peak of current consumption
occurs during GSM single transmit slot in 850/900 MHz
connected-mode, in case of mismatched antenna.
See 1.5.1.2 for 2G connected-mode current profiles.
VCC voltage drop
during 2G Tx slots
Lower than 400 mV
VCC voltage drop directly affects the RF compliance with
applicable certification schemes.
Figure 7 describes VCC voltage drop during Tx slots.
VCC voltage ripple
during 2G/3G Tx
Lower than 30 mVpp if f
ripple
≤ 200 kHz
Lower than 10 mVpp if 200 kHz < f
ripple
≤ 400 kHz
Lower than 2 mVpp if f
ripple
> 400 kHz
VCC voltage ripple directly affects the RF compliance with
applicable certification schemes.
Figure 7 describes VCC voltage ripple during Tx slots.
VCC under/over-shoot
at start/end of Tx slots
Absent or at least minimized
VCC under/over-shoot directly affects the RF compliance
with applicable certification schemes.
Figure 7 describes VCC voltage under/over-shoot.
Table 7: Summary of VCC supply requirements