ics843001agt Integrated Device Technology, ics843001agt Datasheet - Page 8

• Manufacturer Part Number: ics843001agt
• Description: Femto Clocks Crystal-to- 3.3v Lvpecl Clock Generator
• Manufacturer: Integrated Device Technology

P
As in any high speed analog circuitry, the power supply pins
are vulnerable to random noise. The ICS843001 provides
separate power supplies to isolate any high switching
noise from the outputs to the internal PLL. V
should be individually connected to the power supply
plane through vias, and bypass capacitors should be
used for each pin. To achieve optimum jitter performance,
power supply isolation is required. Figure 1 illustrates how
a 10
capacitor should be connected to each V
C
The ICS843001 has been characterized with 18pF parallel
resonant crystals. The capacitor values, C1 and C2, shown in
Figure 2 below were determined using a 26.5625MHz, 18pF
IDT
OWER
RYSTAL
ICS843001
FEMTOCLOCKS™ CRYSTAL-TO-3.3V LVPECL CLOCK GENERATOR
™
/ ICS
resistor along with a 10 F and a .01 F bypass
S
™
I
3.3V LVPECL CLOCK GENERATOR
UPPLY
NPUT
I
F
NTERFACE
ILTERING
T
ECHNIQUES
18pF Parallel Crystal
CCA
A
pin.
X1
PPLICATION
CC
F
IGURE
and V
2. C
CCA
RYSTAL
C1
33p
C2
27p
8
I
NFORMATION
parallel resonant crystal and were chosen to minimize the ppm
error. The optimum C1 and C2 values can be slightly adjusted
for different board layouts.
I
NPU
XTAL_OUT
XTAL_IN
t I
NTERFACE
F
IGURE
1. P
V
V
CCA
CC
ICS843001AG REV B DECEMBER 6, 2006
OWER
.01 F
.01 F
S
UPPLY
3.3V
10
F
10 F
ILTERING