fx604 Consumer Microcircuits Limited, fx604 Datasheet - Page 5

• Manufacturer Part Number: fx604
• Description: V23 Compatible Modem
• Manufacturer: Consumer Microcircuits Limited

V.23 Compatible Modem
1.4
1.5
1.5.1
Frequency and timing accuracy of the FX604 is determined by a 3.579545MHz 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 supplied from
an external source, C1, C2 and X1 should not be fitted.
The on-chip oscillator is turned off in the 'Zero-Power' mode.
If the clock is provided by an external source which 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 significant rise in the supply
current drawn by FX604 as well as generating undefined states of the RXD, DET and RDYN outputs.
1996 Consumer Microcircuits Limited
External Components
General Description
Xtal Osc and Clock Dividers
Figure 2 Recommended External Components for Typical Application
R1
X1
Resistors 5%, capacitors 10% unless otherwise stated.
100k
3.579545MHz
5
C1, C2
C3
C4
18pF
0.1 F
0.1 F
D/604/3
FX604