XE1203 ETC1 [List of Unclassifed Manufacturers], XE1203 Datasheet - Page 35

• Manufacturer Part Number: XE1203
• Description: Low-Power, integrated UHF transceiver
• Manufacturer: ETC1 [List of Unclassifed Manufacturers]

6.5
For narrow band applications, where users select the lowest frequency deviation and the narrowest baseband
filter, the crystal for reference oscillator of the frequency synthesizer must have the following characteristics:
(*) The on-chip oscillator mode is user-defined by programming ADParam_Xsel: the first for CL = 8 pF and C0 = 7
pF, and the second for CL = 8 pF and C0 = 3 pF; the latter will allow higher amplitude for the internal signal with a
slightly lower consumption.
The electrical specifications given in section 3.2.2 are valid for a crystal having the specifications given in table 5.
For applications requiring less frequency stability in terms of signal bandwidth and/or temperature range, it is
possible to use a crystal with larger values for fs(0), fs( T), and/or fs( t). In this case foffset + BWssb should
be lower than BWfilter, where foffset is the offset (error) on the carrier frequency (the sum of fs(0), fs( T), and/or
the base-band filter.
The overtone crystal usage can result higher oscillator start-up time than fundamental mode. The overtone crystal
should be designed for Cload = 8 to 10pF and has parameters of Rm < 60 ohm, C0 < 7pF.
35
fs( t)), BWssb is the single side-band bandwidth of the signal, and BWfilter is the single side-band bandwidth of
REFERENCE CRYSTAL FOR THE FREQUENCY SYNTHESIZER
Name
Fs
CL
Rm
Cm
C0
fs(0)
fs( T)
fs( t)
Description
Nominal frequency
Load capacitance for fs (on-chip)
Motional resistance
Motional capacitance
Shunt capacitance
Calibration tolerance at 25 °C
Stability over temperature range
(-40 °C to 85 °C)
Aging tolerance in first 5 years
Table 5 Crystal characteristics
Min. value
-
-
-
-
-
-
-
-
Typ. value
39.0 MHz
(fundamental)
8 pF (*)
-
-
-
-
-
-
Data Sheet
XE1203
Max. value
-
-
40
30 fF
7 pF (*)
10 ppm
10 ppm
5 ppm
D0308-214