u-blox LEXI-R422, Руководство по системной интеграции

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LEXI-R422 - System integration manual
UBX-23007449 - R02 System description Page 15 of 108
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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.
Voltage must be stable, because during operation, the current drawn by the LEXI-R422 modules
through the
VCC pins can vary by several orders of magnitude, depending on the operating mode and
state (as described in sections 1.5.1.2 , 1.5.1.3 , 1.5.1.4 and 1.5.1.6 ).
It is important that the supply source is able to withstand both the maximum pulse current occurring
during a transmit burst at maximum power level and the average current consumption occurring
during Tx / Rx call at maximum RF power level (see the LEXI-R422 data sheet
[1] ).
LEXI-R422 modules, supporting 2G radio access technology, provide separate supply inputs over the
three
VCC pins:
• VCC pins A13 and A14 represent the supply input for the internal RF power amplifier, demanding
most of the total current drawn of the module when RF transmission is enabled during a call
• VCC pin A12 represents the supply input for the internal baseband power management unit,
demanding minor part of the total current drawn of the module when RF transmission is enabled
during a call
Figure 3 provides a simplified block diagram of LEXI-R422 modules internal VCC supply routing.
A14
VCC
A13
VCC
A12
VCC
LEXI-R422
Power
Management
Unit
Memory
Baseband
Processor
Transceiver
Power
Amplifier
Figure 3: Block diagram of LEXI-R422 modules internal VCC supply routing