XE1203SKC868XE2 Semtech, XE1203SKC868XE2 Datasheet - Page 35

• Manufacturer Part Number: XE1203SKC868XE2
• Description: KIT STARTER FOR XE1203 868MHZ
• Manufacturer: Semtech
• Series: TrueRF™r
• Type: Transceiver, ISMr

Specifications of XE1203SKC868XE2

• Frequency: 868MHz
• For Use With/related Products: XE1203 (868MHz)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

6.5
The values recommended for applications using bit rates up to 38.4kbit/s are given in Table 25 below:
The values recommended for applications using bit rates higher than 38.4 kbit/s are given in Table 26 below:
For narrow band applications, where the lowest frequency deviation and the narrowest baseband filter are
selected, the crystal for reference oscillator of the frequency synthesizer should have the following typical
characteristics:
(*) The on-chip oscillator mode is user-defined by programming ADParam_Xsel parameter: the first for CL = 8 pF
and C0 = 7pF, 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
For wide band applications requiring less frequency stability, the values for Δfs(0), Δfs(ΔT), and/or Δfs(Δt) can be
relaxed. In this case foffset + BWssb should be lower than BWfilter, where foffset is the offset (error) on the carrier
frequency (the sum of Δfs(0), Δfs(ΔT), and/or Δfs(Δt)), BWssb is the single side-band bandwidth of the signal, and
BWfilter is the single side-band bandwidth of the base-band filter.
The overtone crystal usage may result in higher oscillator start-up time than fundamental mode. The overtone
crystal should be designed for Cload = 8 to 10 pF and has parameters of Rm < 60Ω, C0 < 7 pF.
© Semtech 2008
FREQUENCY SYNTHESIZER REFERENCE CRYSTAL
Name
Fs
CL
Rm
Cm
C0
Δfs(0)
Δfs(ΔT)
Δfs(Δt)
Name
Name
CL1
CL2
RL1
CL1
CL2
RL1
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 26: Typical loop filter values for bit rates higher than 38.4 kbit/s
Table 25: Typical loop filter values for bit rates up to 38.4 kbit/s
Typical Value
Typical Value
for 434 MHz
for 434 MHz
220 pF
3.3 nF
1.2 kΩ
1.2 nF
22 nF
560Ω
Table 27: Crystal characteristics
Typical Value
for 868 MHz
Typical Value
for 868 MHz
330 pF
4.7nF
1 kΩ
1.2 nF
22 nF
470Ω
35
Min. value
Typical Value
-
-
-
-
-
-
-
-
for 915 MHz
Typical Value
330 pF
for 915 MHz
4.7 nF
1 kΩ
1.2 nF
22 nF
470Ω
(fundamental)
Typ. value
39.0 MHz
8 pF (*)
-
-
-
-
-
-
Tolerance
Tolerance
± 5%
± 5%
± 5%
± 5%
± 5%
± 5%
Max. value
7 pF (*)
10 ppm
10 ppm
5 ppm
30 fF
XE1203F
40Ω
-
-
www.semtech.com
Table 27
.