Low Power V.22 bis Modem
CMX868
Notes:
I/P
O/P
BI
T/S
NC
=
=
=
=
=
Input
Output
Bidirectional
3-state Output
No Connection
1.4
External Components
R1
X1
C1, C2
C3, C4
C5
22pF
100nF
10uF
100kW
11.0592MHz
or 12.288MHz
Resistors ±5%, capacitors ±20% unless otherwise stated.
Figure 2 Recommended External Components for Typical Application
This device is capable of detecting and decoding small amplitude signals. To achieve this VDD and
VBIAS should be decoupled and the receive path protected from extraneous in-band signals. It is
recommended that the printed circuit board is laid out with a VSS ground plane in the CMX868 area to
provide a low impedance connection between the VSS pins and the VDD and VBIAS decoupling capacitors.
The VSS connections to the Xtal oscillator capacitors C1 and C2 should also be low impedance and
preferably be part of the VSS ground plane to ensure reliable start up of the oscillator.
ã 2004 CML Microsystems Plc
5
D/868/9
CMLMICRO [ CML MICROCIRCUITS ]
