RFM42/43
5.2. Power Amplifier
The RFM42 contains an internal integrated power amplifier (PA) capable of transmitting at output levels between +8 to
+17 dBm. The output power is programmable in 3 dB steps through the txpow[2:0] field in "Register 6Dh. TX Power".
The RFM43 contains a PA which is capable of transmitting output levels between –8 to +13 dBm.
5.2.1. Output Power Selection
With the RFM42, the output power is configurable in 3 dB steps from +8 to +17 dBm with the txpow[2:0] field in
"Register 6Dh. TX Power". The PA output is ramped up and down to prevent unwanted spectral splatter.The higher
power setting of the module achieves maximum possible range, but of course comes at the cost of higher TX current
consumption. However, depending on the duty cycle of the system, the effect on battery life may be insignificant.
Contact HopeRF Support for help in evaluating this tradeoff.
The +13 dBm output power of the RFM43 is targeted at systems that require lower output power. The PA still offers
high efficency and a range of output power from –8 to +13 dBm.
D7
D6
D5
D4
D3
D2
D1
D0
POR Def.
Add R/W Function/Description
R/W
TX Power
txpow[2] txpow[1]
txpow[0]
07h
6D
txpow[1:0]
RFM42 Output Power
00
+8 dBm
01
10
11
+11 dBm
+14 dBm
+17 dBm
txpow[2:0]
RFM43 Output Power
000
–8 dBm
001
010
011
100
101
110
111
–5 dBm
–2 dBm
+1 dBm
+4 dBm
+7 dBm
+10 dBm
+13 dBm
27
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E-mail: sales@hoperf.com
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