Ublox LENA-R8 Series, System Integration Manual

Page: 17 / 116

LENA-R8 series - System integration manual
UBX-22015376 - R02 System description Page 17 of 116
C1-Public
1.6.1.1 VCC supply requirements
Table 5 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 5 .
⚠
VCC supply circuit affects the RF compliance of the device integrating LENA-R8 series modules
with applicable required certification schemes as well as antenna circuit design. RF performance
is optimized by fulfilling the requirements for the
VCC supply summarized in Table 5 .
Item Requirement Remark
VCC nominal voltage Within VCC normal operating range:
3.4 V min. / 4.2 V max.
Operating within 3GPP / ETSI specifications: RF
performance is optimized when
VCC PA voltage is inside
the normal operating range limits.
VCC voltage during
normal operation
Within VCC extended operating range:
3.2 V min. / 4.5 V max.
Operating with possible slight deviation in RF
performance outside normal operating range.
VCC voltage must be above the extended operating range
minimum limit to switch-on the module and to avoid
possible switch-off of the module.
Operation above
VCC extended operating range is not
recommended and may affect device reliability.
VCC average current Support with adequate margin the highest
averaged VCC current consumption value
in connected mode conditions specified in
the LENA-R8 series data sheet
[1]
The highest averaged VCC current consumption can be
greater than the specified value according to the actual
antenna mismatching, temperature and
VCC voltage.
For a safe design margin, use a VCC supply source that
can deliver double the typical average VCC current
consumption at maximum Tx power, normal ambient
temperature and normal voltage condition shown in the
LENA-R8 series data sheet
[1] .
See 1.6.1.3 / 1.6.1.2 for connected mode current profiles.
VCC peak current Support with margin the highest peak VCC
current consumption value in connected
mode conditions specified in the LENA-R8
series data sheet
[1]
The specified highest peak of VCC current consumption
occurs during GSM single transmit slot in 850/900 MHz
connected mode, in case of a mismatched antenna.
See
1.6.1.3 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/LTE Tx
Noise in the supply must be minimized
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 5: Summary of VCC supply requirements
1.6.1.2 VCC consumption in LTE connected mode
During an LTE connection, the module may transmit and receive continuously due to the frequency
division duplex (FDD) mode of operation or it may transmit and receive alternatively due to the time
division duplex (TDD) mode of operation available with LTE radio access technology.
The current consumption depends on output RF power, which is always regulated by the network (the
current base station), sending power control commands to the module, indicating a maximum output
RF power of approximately 0.25 W down to a minimum output RF power of approximately 0.1
µ
W, so
that the current consumption may vary a lot as illustrated in Figure 5, showing an example of current
consumption profile versus time in the LTE FDD connected mode. Detailed current consumption
values can be found in LENA-R8 series data sheet
[1] .