SX1276 View Datasheet(PDF) - Semtech Corporation
Part Name
Description
MFG CO.
'SX1276' PDF : 132 Pages View PDF
SX1276/77/78/79
WIRELESS, SENSING & TIMING
DATASHEET
Table 38 LNA Gain Control and Performances
RX input level (Pin)
Pin <= AgcThresh1
AgcThresh1 < Pin <= AgcThresh2
AgcThresh2 < Pin <= AgcThresh3
AgcThresh3 < Pin <= AgcThresh4
AgcThresh4 < Pin <= AgcThresh5
AgcThresh5 < Pin
Gain
Setting
LnaGain
Relative LNA
Gain [dB]
G1
‘001’
G2
‘010’
G3
‘011’
G4
‘100’
G5
‘110’
G6
‘111’
0 dB
-6 dB
-12 dB
-24 dB
-26 dB
-48 dB
NF
Band 3/2/1
[dB]
4/5.5/7
6.5/8/12
11/12/17
20/21/27
32/33/35
44/45/43
IIP3
Band 3/2/1
[dBm]
-15/-22/-11
-11/-15/-6
-11/-12/0
2/3/9
10/10/14
11/12/14
5.5.4. RSSI in FSK/OOK Mode
The RSSI provides a measure of the incoming signal power at RF input port, measured within the receiver bandwidth. The
signal power is available in RssiValue. This value is absolute in units of dBm and with a resolution of 0.5 dB. The formula
below relates the register value to the absolute input signal level at the RF input port:
RssiValue = −2 ⋅ RF level [dBm]+ RssiOffset [dB]
The RSSI value can be compensated to take into account the loss in the matching network or even the gain of an
additional LNA by using RssiOffset. The offset can be chosen in 1 dB steps from -16 to +15 dB. When compensation is
applied, the effective signal strength is read as follows:
RSSI
[dBm]
=
−
RssiValue
2
The RSSI value is smoothed on a user defined number of measured RSSI samples. The precision of the RSSI value is
related to the number of RSSI samples used. RssiSmoothing selects the number of RSSI samples from a minimum of 2
samples up to 256 samples in increments of power of 2. Table 39 gives the estimation of the RSSI accuracy for a 10 dB
SNR and response time versus the number of RSSI samples programmed in RssiSmoothing.
Table 39 RssiSmoothing Options
RssiSmoothing
‘000’
‘001’
‘010’
‘011’
‘100’
‘101’
‘110’
‘111’
Number of Samples
2
4
8
16
32
64
128
256
Estimated Accuracy
± 6 dB
± 5 dB
± 4 dB
± 3 dB
± 2 dB
± 1.5 dB
± 1.2 dB
± 1.1 dB
Response Time
2 (RssiSmoothing +1)
4 ⋅ RxBw[kHz]
[ms]
The RSSI is calibrated when the image and RSSI calibration process is launched.
Rev. 4 - March 2015
©2015 Semtech Corporation
Page 86
www.semtech.com
Share Link: 
