TOBY-L2 and MPCI-L2 series - System Integration Manual
UBX-13004618 - R07
Advance Information
System description
Page 24 of 158
1.5.1.3
VCC or 3.3Vaux current consumption in 3G connected mode
During a 3G connection, the module can transmit and receive continuously due to the Frequency Division Duplex
(FDD) mode of operation with the Wideband Code Division Multiple Access (WCDMA).
The current consumption depends again on output RF power, which is always regulated by network commands.
These power control commands are logically divided into a slot of 666 µs, thus the rate of power change can
reach a maximum rate of 1.5 kHz.
There are no high current peaks as in the 2G connection, since transmission and reception are continuously
enabled due to FDD WCDMA implemented in the 3G that differs from the TDMA implemented in the 2G case.
In the worst scenario, corresponding to a continuous transmission and reception at maximum output power
(approximately 250 mW or 24 dBm), the average current drawn by the module at the VCC pins is high (see the
“
Current consumption
” section in
TOBY-L2 Data Sheet
[1] or in
MPCI-L2 Data Sheet
[2]). Even at lowest output
RF power (approximately 0.01 µW or -50 dBm), the current is still not so low due to module baseband
processing and transceiver activity.
Figure 7 shows an example of current consumption profile of the module in 3G WCDMA/DC-HSPA+ continuous
transmission mode.
Time
[ms]
3G frame
10 ms
(1 frame = 15 slots)
Current [mA]
Current consumption value
depends on TX power and
actual antenna load
170 mA
1 slot
666 µs
850 mA
0
300
200
100
500
400
600
700
Figure 7: VCC or 3.3Vaux current consumption profile versus time during a 3G connection (TX and RX continuously enabled)
