Semtech LR1121 - PA Current Consumption; Low Power PA; Figure 9-8: IDDTX Vs Txpower, Low Power PA, DC-DC Configuration

LR1121
User Manual Rev 1.1
UM.LR1121.W.APP Mar 2023
91 of 130
Semtech
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9.3 PA Current Consumption
9.3.1 Low Power PA
Figure 9-8: IDDTX vs TxPower, Low Power PA, DC-DC Configuration shows the impact of the supply voltage for three
PaDutyCycle settings (0, 4 and 7) in DC-DC configuration.
At a given supply voltage, a higher PaDutyCycle setting increases the device current consumption. At a given PaDutyCycle
setting, the current consumption is optimum for a supply voltage equal or greater to 3.3V, therefore the plots for 3.3V and
3.7V are superimposed. A power supply of 1.8V is not be as power efficient as 3.3V or more, resulting in a higher current
consumption.
For example:
• For 3.7V, PaDutyCycle=0 the current consumption is approx. 28mA, for PaDutyCycle=4 approx. 47mA and for
PaDutyCycle=7 approx. 62mA.
• For PaDutyCycle=4, the current consumption is approx. 47mA for 3.3V and 3.7V, and approx. 49mA for 1.8V.
Figure 9-8: IDDTX vs TxPower, Low Power PA, DC-DC Configuration