CMX644AD2 Ver la hoja de datos (PDF) - MX-COM Inc
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Lista de partido
CMX644AD2 Datasheet PDF : 31 Pages
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Bell 212A / V.22 Modem with Call Progress and DTMF
6
3 External Components
VDD
R1
C1
XTAL
C2
X1
XTAL/CLOCK
SERIAL CLOCK
C-BUS
to/from
µC
COMMAND DATA
REPLY DATA
CS
IRQ
TX
Tx Line
Interface.
See 5.1
TX+
TXIN-
TX-
VSS
1
24
2
23
3
22
4
21
5
20
6 CMX644A 19
7 D5/D2/P4 18
8
17
9
16
10
15
11
14
12
13
CMX644A Preliminary Information
VDD
A/D CAP
N/C
C5
N/C
N/C
RD
RT
RXAMPOUT
RX-
RX+
RLYDRV
VBIAS
C4
C3
To/from Ring
Detector.
See 5.2
Rx Line
Interface.
See 5.1
Relay Drive
Figure 2: Recommended External Components
R1
C1, C2
C3, C4,
C5
X1
Note 1
100kΩ
18pF
0.1µF
1µF
3.6864MHz, 7.372800MHz or
11.0592MHz
±1%
±20%
±20%
±20%
Tolerances for Resistors and Capacitors are as indicated unless otherwise stated.
Table 2: Recommended External Components for Typical Application
Recommended External Component Notes on Xtal Osc and Clock Dividers
1. R1 should be selected so that the IRQ pin has returned to its normal (high) state before CS pin goes
high.
2. Frequency and timing accuracy of the CMX644A is determined by the clock present at the XTAL/CLOCK
pin. This may be generated by the on-chip oscillator inverter using the external components C1, C2 and
X1 of Figure 2, or may be supplied from an external source to the XTAL/CLOCK input. If the clock is
supplied from an external source, C1, C2 and X1 should not be fitted.
3. The on-chip oscillator is turned off in the 'Zero-Power' mode.
4. If the clock is provided by an external source that is not always running, then the 'Zero-Power' mode must
be set when the clock is not available. Failure to observe this rule may cause a rise in the supply current
drawn by CMX644A.
5. For best results, a crystal oscillator design should drive the clock inverter input with signal levels of at
least 40% of VDD, peak to peak. Tuning fork crystals generally cannot meet this requirement. To obtain
crystal oscillator design assistance, please consult your crystal manufacturer.
2000 MX-COM, Inc.
www.mxcom.com tel: 800 638 5577 336 744 5050 fax: 336 744 5054
Doc. # 20480197.006
4800 Bethania Station Road, Winston-Salem, NC 27105-1201 USA All trademarks and service marks are held by their respective companies.
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