SX1239IMLTRT Semtech, SX1239IMLTRT Datasheet - Page 19

• Manufacturer Part Number: SX1239IMLTRT
• Description: IC, RF RECEIVER, 1.02GHz, QFN-24
• Manufacturer: Semtech

Specifications of SX1239IMLTRT

• Applications: Wireless Sensor Networks, Automated Meter Reading, Home And Building Automation
• Receiving Current: 16mA
• Data Rate: 300Kbps
• Modulation Type: FSK, OOK
• Sensitivity Dbm: -120dBm
• Rohs Compliant: Yes
• Rf Ic Case Style: QFN
• No. Of Pins: 24
• Sensitivity (dbm): -120dBm
• Supply Voltage Range: 1.8V To 3.6V
• Operating Temperature Range: -40°C To +85°C
• Lead Free Status / Rohs Status: Supplier Unconfirmed

The following figure illustrates the AGC behavior::
The following table summarizes the performance (typical figures) of the complete receiver:
Table 9
3.4.3.1. RssiThreshold Setting
For correct operation of the AGC, RssiThreshold in RegRssiThresh must be set to the sensitivity of the receiver. The
receiver will remain in WAIT mode until RssiThreshold is exceeded.
Note
3.4.3.2. AGC Reference
The AGC reference level is automatically computed in the SX1239, according to:
Rev 3 - Jan 2011
ADVANCED COMMUNICATIONS & SENSING
AGC Reference [dBm] = -174 + NF + DemodSnr +10.log(2*RxBw) + FadingMargin [dBm]
-125 dBm
When AFC is enabled and performed automatically at the receiver startup, the channel filter used by the receiver
during the AFC and the AGC is RxBwAfc instead of the standard RxBw setting. This may impact the sensitivity of
the receiver, and the setting of RssiThreshold accordingly
Towards
Receiver Performance Summary
Lower Noise Figure
Higher Sensitivity
G1
Lower Linearity
AgcThresh1 < Pin < AgcThresh2
AgcThresh2 < Pin < AgcThresh3
AgcThresh3 < Pin < AgcThresh4
AgcThresh4 < Pin < AgcThresh5
Pin < AgcThresh1
AgcThresh5 < Pin
16dB
Input Power
Pin
Figure 6. AGC Thresholds Settings
G2
7dB
Setting
Gain
G1
G2
G3
G4
G5
G6
Page 19
G3
11dB
[dBm]
P
-37
-31
-26
-14
>-6
>0
-1dB
Receiver Performance (typ)
G4
9dB
[dB]
NF
13
18
27
36
44
7
11dB
[dBm]
G5
IIP3
+13
+20
-18
-15
-8
-1
Higher Noise Figure
Lower Sensitivity
Higher Linearity
[dBm]
IIP2
G6
+35
+40
+48
+62
+68
+75
DATASHEET
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SX1239
Pin [dBm]