Integrated
Circuit
Systems, Inc.
ICS8431-21
350MH
Z
, L
OW
J
ITTER
, C
RYSTAL
O
SCILLATOR
-
TO
-3.3V LVPECL F
REQUENCY
S
YNTHESIZER
Figure 5B.
This layout example is used as a general guideline.
The layout in the actual system will depend on the selected
component types and the density of the P.C. board.
L
AYOUT
G
UIDELINE
The schematic of the ICS8431-21 layout example used in this
layout guideline is shown in
Figure 5A.
The ICS8431-21 rec-
ommended PCB board layout for this example is shown in
Logic Input Pin Examples
VCC=3.3V
SP=Spare, not installed
RU1
1K
C6
0.01uF
U1
C8
1
2
3
4
5
6
7
8
9
10
11
12
13
14
M0
M1
M2
M3
M4
M5
M6
M7
M8
SSC_CTL0
SSC_CTL1
VEE
TEST_IO
VCC
nP_LOAD
VCC
XTAL_IN
XTAL_OUT
NC
NC
VCCA
VEE
MR
DIV_SEL
VCCO
FOUT
nFOUT
VEE
28
27
26
25
24
23
22
21
20
19
18
17
16
15
22pF
RD1
SP
X1
C7
22pF
R5
VCCA
VCC
C3
0.01uF
C4
10uF
10
Zo = 50 Ohm
VCC
R1
125
R3
125
+
VCC
VCC
Set Logic
Input to
'1'
VCC
Set Logic
Input to
'0'
RU2
SP
VCC
To Logic
Input
pins
RD2
1K
To Logic
Input
pins
VCC
Zo = 50 Ohm
C1
0.1uF
ICS8431-21
C2
0.1uF
R2
84
R4
84
-
F
IGURE
5A. S
CHEMATIC
E
XAMPLE
8431AM-21
www.icst.com/products/hiperclocks.html
10
REV. A APRIL 27, 2005
ICS [ INTEGRATED CIRCUIT SYSTEMS ]
