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NXP Semiconductors
AN11022
CLRC663 Quickstart Guide
2.4 Crystal oscillator
The clock applied to the CLRC663 acts as a time basis for generation of the carrier sent
out at TX, for the quadrature mixer I and Q clock generation, and for the coder and
decoder of the synchronous system. Therefore, stability of the clock frequency is an
important factor for proper performance. To obtain highest performance, clock jitter has
to be as small as possible. This is best achieved by using the internal oscillator buffer
with the recommended circuitry.
Fig 3. Crystal connection
Table 2. Crystal requirements recommendations
Symbol
Parameter
min
Typ
max
Unit
fxtal
Crystal frequency
27.12
MHz
∆fxtal
Crystal frequency accuracy
-250
+250
ppm
ESR
Equivalent series resistant
50
100
Ω
CL
Load capacitance
10
pF
Pxtal
Crystal power dissipation
50
100
uW
2.5 Receiver circuit
The Receiver is a fully differential circuit and can be used double ended or single
ended:
 For single ended use (Quasi- Differential) of the receiver circuit it is strongly
recommended to connect RxN and RxP to each other or to connect them by
using the Rcv_Reg register (address 38h).But if the Rcv_Rx_single bit in the
Rcv_Reg register is set to 1 -> Quasi-Differential, the unused Rx pin has to
be open and not connected to Ground.
 For double ended use connect RxN and RxP, as recommended, to the
transmitter circuit, directly after the EMC filter.
AN11022 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2015. All rights reserved.
Application note
COMPANY PUBLIC
Rev. 1.2 — 14 January 2015
205912
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