Low Power Pa; Figure 9-3: Low Power Pa Vr_Pa Voltage Vs - Semtech LR1121 User Manual

9.1.1 Low Power PA

For maximum efficiency, the low power PA should be operated with a maximum VR_PA near 1.35V.
To get VR_PA = 1.35V the user should set TxPower = 14. At this setting:
• The PA can deliver up to 15dBm output power, constant over the specified battery supply range
• The actual maximum output power can be set according to the duty cycle setting (PaDutyCycle)
• If needed, the output power can be decremented in steps of 1dB from maximum by using TxPower < 14
The VR_PA variation over the programmed power TxPower for different supply voltages and PaDutyCycle conditions is
depicted in

Figure 9-3: Low Power PA VR_PA Voltage vs.

DCDC configurations).
Note: All figures in this chapter are indicative and typical, and are not a specification. These figures only highlight the
behavior of the PA over the various parameters and conditions.
LR1121
User Manual Rev 1.1
UM.LR1121.W.APP Mar 2023
TxPower below (valid for VBAT and VREG supplies, in both LDO or
Figure 9-3: Low Power PA VR_PA Voltage vs. TxPower
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