840001CK-32

www.icst.com/products/hiperclocks.html

REV. A NOVEMBER 23, 2005

7

Integrated

Circuit

Systems, Inc.

ICS840001-32

PRELIMINARY

The ICS840001-32 has been characterized with 10pF paral-

lel resonant crystals. The capacitor values, C1 and C2, shown

in Figure 2 below were determined using a 40MHz, 10pF

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.

As in any high speed analog circuitry, the power supply pins are

vulnerable to random noise. The ICS840001-32 provides sepa-

rate power supplies to isolate any high switching noise from

the outputs to the internal PLL. V

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

Ω resistor along with

a 10

μF and a .01μF bypass capacitor should be connected to

each V

Ω resistor can also be replaced by a

ferrite bead.

10

Ω

V

DDA

10

μF

.01

μF

3.3V

.01

μF

V

DD

C1

X1

Crystal

C2

XTAL_IN

XTAL_OUT