SM1211E915TOPIC Semtech, SM1211E915TOPIC Datasheet - Page 66

• Manufacturer Part Number: SM1211E915TOPIC
• Description: KIT PICTAIL EXT FOR SX1211
• Manufacturer: Semtech
• Type: Transceiver, UHFr

Specifications of SM1211E915TOPIC

• Frequency: 915MHz
• For Use With/related Products: SX1211
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

7. Application Information
Table 34 shows the crystal resonator specification for the crystal reference oscillator circuit of the SX1211. This
specification covers the full range of operation of the SX1211 and is employed in the reference design (see section
7.5.3).
Table 34: Crystal Resonator Specification
Note that the initial frequency tolerance, temperature stability and ageing performance should be chosen in
accordance with the target operating temperature range and the receiver bandwidth selected.
The R1, P1, S1, and R2, P2, S2 dividers are configured over the SPI interface and programmed by 8 bits each, at
addresses 6 to 11. The frequency pairs may hence be switched in a single SPI cycle.
To aid the user with calculating appropriate R, P and S values, software is available to perform the frequency
calculation. The SX1211 PLL frequency Calculator Software can be downloaded from the Semtech website.
The Dynamically Linked Library (DLL) used by the software to perform these calculations is also provided, free of
charge, to users, for inclusion in automatic production testing. Key benefits of this are:
As an ultra-low power device, the SX1211 can be configured for low minimum average power consumption. To
minimize consumption the following optimized transitions between modes are shown.
Rev 7 – Sept 2
ADVANCED COMMUNICATIONS & SENSING
Name
Fxtal
Cload
Rm
Co
Fxtal
Fxtal( T)
Fxtal( t)
7.1. Crystal Resonator Specification
7.2. Software for Frequency Calculation
No hand trimming of the reference frequency required: the actual reference frequency of the Device Under Test
(DUT) can be easily measured (e.g. from the CLKOUT output of the SX1211) and the tool will calculate the
best frequencies to compensate for the crystal initial error.
Channel plans can be calculated and stored in the application’s memory, then adapted to the actual crystal
oscillator frequency.
7.3. Switching Times and Procedures
7.2.1. GUI
7.2.2. .dll for Automatic Production Bench
nd
, 2008
Description
Nominal frequency
Load capacitance for Fxtal
Motional resistance
Shunt capacitance
Calibration tolerance at 25+/-3° C
Stability over temperature range [-40° C ; +85° C]
Ageing tolerance in first 5 years
Page 66 of 92
Min.
-2 0
-15
10
-2
9
1
-
Typ.
12.800
15
-
-
-
-
-
Max.
+15
16.5
+20
100
15
+2
7
ppm
Unit
MHz
pF
ohms
pF
ppm
ppm/year
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SX1211