Integrated
Circuit
Systems, Inc.
ICS8442
700MH
Z
, C
RYSTAL
O
SCILLATOR
-
TO
-D
IFFERENTIAL
LVDS F
REQUENCY
S
YNTHESIZER
suitable for most applications. Additional accuracy can be
achieved by adding two small capacitors C1 and C2 as shown in
Figure 3.
Typical results using parallel 18pF crystals are shown
in Table 10.
C
RYSTAL
I
NPUT
I
NTERFACE
A crystal can be characterized for either series or parallel mode
operation. The ICS8442 has a built-in crystal oscillator circuit.
This interface can accept either a series or parallel crystal without
additional components and generate frequencies with accuracy
25
C1
18p
X1
18pF Parallel Crystal
24
C2
22p
XTAL2
XTAL1
ICS8442
Figure 3. C
RYSTAL
I
NPU
t I
NTERFACE
LVDS D
RIVER
T
ERMINATION
A general LVDS interface is shown in
Figure 4.
In a 100Ω differ-
ential transmission line environment, LVDS drivers require a
matched load termination of 100Ω across near the receiver in-
put. For a multiple LVDS outputs buffer, if only partial outputs
are used, it is recommended to terminate the un-used outputs.
3.3V
3.3V
Zo = 50 Ohm
LVDS_DRIVER
R1
100
CLK
nCLK
Zo = 50 Ohm
HiPerClockS
100Ω Differential Transmission Line
Ω
F
IGURE
4. T
YPICAL
LVDS D
RIVER
T
ERMINATION
8442AY
www.icst.com/products/hiperclocks.html
9
REV. C JULY 8, 2004
ICSI [ INTEGRATED CIRCUIT SOLUTION INC ]
