SM1212E433 Semtech, SM1212E433 Datasheet - Page 22

• Manufacturer Part Number: SM1212E433
• Description: RF Module For SX1212
• Manufacturer: Semtech
• Series: -r
• Type: Transceiver, ISMr

Specifications of SM1212E433

• Frequency: 433MHz
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant
• For Use With/related Products: SX1212E

The recommended PA bias and matching circuit is illustrated below:
Please refer to section 7.5.3 of this document for the optimized matching arrangement for each frequency band.
The receiver and the transmitter share the same RFIO pin (pin 31). Figure 13 below shows the configuration of the
common RF front-end.
Rev 2 – June 18th, 2009
ADVANCED COMMUNICATIONS & SENSING
In transmit mode, the PA and the PA regulator are active, with the voltage on the VR_PA pin equal to the
nominal voltage of the regulator (1.8 V). The external inductance is used to bias the PA.
In receive mode, both PA and PA regulator are off and VR_PA is tied to ground. The external inductance LT1
is then used to bias the LNA.
3.3.8. Common Input and Output Front-End
3.3.7.3. Suggested PA Biasing and Matching
Figure 12: Recommended PA Biasing and Output Matching
PA
To
VR_PA
RFIO
Figure 13: Front-end Description
VR_PA
RFIO
100nH
Low-pass and DC block
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47nF
Rx_on
Reg_PA
LNA
PA
SAW
DC block
Antenna
port
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SX1212