LR1110
User Manual
Rev.1.0
UM.LR1110.W.APP
March 2020
75 of 130
Semtech
Figure 9-5: Low Power PA Output Power vs.
TxPower
9.2.2 High Power PA
Figure 9-6: HP PA Output Power vs. TxPower
shows the output power of the High Power PA with
TxPower
for different
PaDutyCycle
settings and over the supply voltage.
For a given
PaDutyCycle
, the output power of the High Power PA is maintained on a certain voltage range, and then
decreases with VBAT. For example:
•
For the +22dBm power setting, a VR_PA of ~3.1 V is required (refer to
). Therefore, given the 200 mV drop-out
of the PA regulator, the +22 dBm output power can only be obtained from a 3.3 V to 3.7 V supply voltage range.
•
For +17dBm, VR_PA around 2 V is required. Therefore the LR1110 output power will drop to +17 dBm for the minimum
supply voltage 1.8 V.
Therefore, the plots for 3.3V and 3.7V are then superimposed for a given
PaDutyCycle
, and only the plots for 3.7V are visible.
For a given supply voltage, increasing the
PaDutyCycle
increases the output power.
For example:
•
For the +22dBm power setting at 3.3V,
PaDutyCycle
=4 allows the High Power PA to d22dBm
•
For the +22dBm power setting at 3.3V,
PaDutyCycle
=2 allows the High Power PA to d20dBm
