ics841s04 Integrated Device Technology, ics841s04 Datasheet - Page 10

• Manufacturer Part Number: ics841s04
• Description: Programmable Low-jitter Xtal Or Lvcmos-input Hcsl-output 4-output 100-mhz Clock Synthesizer
• Manufacturer: Integrated Device Technology

As in any high speed analog circuitry, the power supply pins
are vulnerable to random noise. The ICS841S04I provides sepa-
rate power supplies to isolate any high switching
noise from the outputs to the internal PLL. V
V
through vias, and bypass capacitors should be used for each
pin. To achieve optimum jitter performance, power supply iso-
lation is required. Figure 1 illustrates how a 10
with a 10µF and a .01 F bypass capacitor should be connected
to each V
bead.
U
The
minimize system implementation costs. The
operated with a 25MHz crystal and without additional components.
Recommended operation for the crystal should be of a parallel
resonant type and a load specification of C
for complete crystal specifications.
If more precise frequency control is desired, the addition of
capacitors from each of the XTAL_IN and XTAL_OUT pins to
ground may be used to trim the frequency as shown in Figure 2.
T
IDT
P
P
R
L
E
C
S
DDA
ABLE
SING THE
OWER
ICS841S04I
PCI EXPRESS™ CLOCK GENERATOR
o
a
q
y r
e
h
™
a
a r
i u
s
u
t s
ICS841S04I
d
/ ICS
o
should be individually connected to the power supply plane
t n
a v
m
n
l a
C
7. R
a
C
e l
t e
a
n
C
™
S
a
DDA
p
t n
r e
c
t u
p
a
PCI EXPRESS™ CLOCK GENERATOR
e
UPPLY
ECOMMENDED
a
i c
S
. The 10
O
i c
a t
r e
a t
N
n
e i
-B
n
c
s
c
features a fully integrated Pierce oscillator to
e
F
e
R
OARD
(
ILTERING
C
(
e
C
s
O
resistor can also be replaced by a ferrite
L
)
s i
)
a t
C
C
RYSTAL
n
c
RYSTAL
e
T
E (
ECHNIQUES
S
S
R
PECIFICATIONS
)
O
1
F
P
5
2
SCILLATOR
V
8
u
7 -
a
r a
0
p
u l
n
5 -
l a
p
F
L
d
F
e
0
A
ICS841S04I
a
l e l
= 18pF. See Table 7
m
DD_REF
PPLICATION
R
e
t n
e
s
resistor along
l a
o
, V
n
A
a
T
DD_SRC,
n
C
c
may be
e
t u
and
10
I
NFORMATION
The crystal and optional trim capacitors should be located as
close to the
to avoid any board level parasitic.
F
IGURE
25MHz
ICS841S04I
F
2. C
IGURE
RYSTAL
1. P
V
DD_REF
V
XTAL_IN and XTAL_OUT pins as possible
DDA
OWER
O
SCILLATOR
TBD
TBD
33pF
18pF
ICS841S04BGI REV. C MAY 23, 2007
.01 F
.01 F
S
UPPLY
3.3V
W
XT AL_IN
XTAL_OUT
F
10
ITH
10 F
ILTERING
PRELIMINARY
T
RIM
C
APACITOR