XE1283SKC915XE1 Semtech, XE1283SKC915XE1 Datasheet - Page 21

• Manufacturer Part Number: XE1283SKC915XE1
• Description: KIT STARTER FOR XE1283 915MHZ
• Manufacturer: Semtech
• Series: TrueRF™r
• Type: Transceiverr

Specifications of XE1283SKC915XE1

• Contents: Processor Boards, Modules, Batteries, Antennas, Serial Cable and Software CD
• For Use With/related Products: XE1283 (915MHz)
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

5.1.1.5
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 should have the following characteristics:
(*) The on-chip oscillator mode is user-defined by programming ADParam_Xsel in the configuration register: 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. For the explanation of this parameter ADParam_Xsel, please refer to the
XE1203F datasheet.
The electrical specifications given in section 3.2.3 are valid for a crystal having the specifications given in the table above.
For wide band applications requiring less frequency stability, the values for ∆fs(0), ∆fs(∆T), and/or ∆fs(∆t) 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 ∆fs(0), ∆fs(∆T), and/or ∆fs(∆t)), 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 can result in 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.
5.1.2
5.1.2.1
This capacitor is compulsory and must be connected between pin VREG and ground.
5.1.2.2
This reference crystal must be mounted between XIN and XOUT and is used by the software DFLL to set precisely the
RC’s frequency.
© Semtech 2005
Description
Capacitor on VREG
MicroController
Reference crystal
Vreg capacitor
Reference crystal
∆fs(∆T)
∆fs(∆t)
Name
∆fs(0)
Rm
Cm
CL
C0
Fs
Load capacitance for fs (on-chip)
Stability over temperature range
Aging tolerance in first 5 years
Calibration tolerance at 25 °C
Motional capacitance
Motional resistance
Nominal frequency
Shunt capacitance
(-40 °C to 85 °C)
Description
Min
0.8
21
Min. value
-
-
-
-
-
-
-
-
Typ
1
(fundamental)
Typ. value
39.0 MHz
8 pF (*)
-
-
-
-
-
-
Max
1.2
Max. value
7 pF (*)
10 ppm
10 ppm
5 ppm
XE1283
30 fF
40 Ω
-
-
Unit
www.semtech.com
µF