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
[1] and in
the
SARA-U2 series Data Sheet
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
[1] and in
the
SARA-U2 series Data Sheet
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
