ICS843020-01 Datasheet, PDF (13/20 Pages) Integrated Circuit Systems – FEMTOCLOCKS-TM 680MHZ, CRYSTAL-TO- 3.3V DIFFERENTIAL LVPECL FREQUENCY SYNTHESIZER

Integrated
Circuit
Systems, Inc.
ICS843020-01
FEMTOCLOCKS™ 680MHZ, CRYSTAL-TO-
3.3V DIFFERENTIAL LVPECL FREQUENCY SYNTHESIZER
LAYOUT GUIDELINE
The schematic of the ICS843020-01 layout example used in
this layout guideline is shown in Figure 5A. The ICS843020-
01 recommended PCB board layout for this example is shown
in Figure 5B. This layout example is used as a general guide-
line. The layout in the actual system will depend on the se-
lected component types, the density of the components, the
density of the traces, and the stack up of the P.C. board.
VCC
Float
R5
1K
'1'
'0'
R6
1K
U1
1
2
3
4
M5
M6
M7
5
6
7
8
M8
N0
N1
P_DIV
VEE
ICS843020-01
Logic Input Pin Examples
C14
Set Logic
Set Logic
0.1u
VCC _{Input to}
VCC _{Input to}
'1'
'0'
RU1
1K
RU2
Not Install
To Logic
Input
pins
RD1
Not Install
To Logic
Input
pins
RD2
1K
C1
C2
X1
VCC
XTAL_O
T_CLK
nXTAL_SEL
24
23
22
21
REF_IN
XTAL_SEL
VCCA
S_LOAD
S_DATA
S_CLOCK
20
19
18
17
S_LOAD
S_DATA
S_CLOCK
MR
VCCA
C11
0.01u
R7
10
C16
10u
C15
0.1u
Zo = 50 Ohm
TL1
Zo = 50 Ohm
TL2
VCC
R1
R3
133
133
+
R2
82.5
-
R4
82.5
FIGURE 5A. SCHEMATIC OF RECOMMENDED LAYOUT
843020AY-01
www.icst.com/products/hiperclocks.html
13
REV. B APRIL 14, 2005