CN8330EPD CONEXANT [Conexant Systems, Inc], CN8330EPD Datasheet - Page 99

• Manufacturer Part Number: CN8330EPD
• Description: DS3/E3 Framer with 52 Mbps HDLC Controller
• Manufacturer: CONEXANT [Conexant Systems, Inc]

100441E
From VCO
To VCXO
Output
Control
Appendix C
Here's what we've recommended as a starting point for those customers who need
a jitter attenuation PLL for TBR24 compliance in E3 mode.
VCXO and a passive LPF (low pass filter). The VCO output from CN8330 is
passed through the LPF to create a control voltage input to the VCXO. The
VCXO output then connects to RXCKI (and optionally to TXCKI) input of
CN8330.
Center Frequency:
Frequency Accuracy:
Frequency Pullability:
Note: +/- 100 ppm frequency pullability may be adequate.
the filter's cutoff frequencies as follows:
Input
T1 = R1 x C2
T2 = R2 x C2
T3 = R2 x C1
An external jitter attenuation PLL can be implemented for CN8330 with one
The LPF circuit is shown below with the RC time constants used to establish
R and C values shown above are calculated for typical applications.
VCXO Specifications:
1 M
R1
Conexant
1 M
10 nF
R2
C
C1
+/- 200
44.736
+/- 20
T3
100 nF
C2
+/- 200
34.368
+/- 20
(Analog)
E3
GND
Units
MHz
ppm
ppm
8330_001
C-1