Integration Manual

Table Of Contents
TOBY-L2 and MPCI-L2 series - System Integration Manual
UBX-13004618 - R26 System description
Page 26 of 162
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 on output RF power, which is always regulated by the network (the current
base station) sending power control commands to the module. 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 considerable
(see the Current consumptionsection in TOBY-L2 Data Sheet [1] or in MPCI-L2 Data Sheet [2]). At the lowest
output RF power (approximately 0.01 µW or 50 dBm), the current drawn by the internal power amplifier is
strongly reduced. The total current drawn by the module at the VCC pins is due to 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)