Integrated

Circuit

Systems, Inc.

8400042AG

www.icst.com/products/hiperclocks.html

REV. A SEPTEMBER 16, 2004

10

ICS840004

PRELIMINARY

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

are vulnerable to random noise.The ICS840004 provides sepa-

rate 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

Ω resistor along with a 10µF and a .01µF bypass

capacitor should be connected to each V

10

Ω

V

DDA

10

µF

.01

µF

3.3V

.01

µF

V

DD

The ICS840004 has been characterized with 18pF parallel reso-

nant crystals.The capacitor values shown in

Figure 2 below were

determined using a 26.5625MHz 18pF parallel resonant crystal and

were chosen to minimize the ppm error.

ICS84332

XTAL_IN

XTAL_OUT

X1

18pF Parallel Cry stal

C2

22p

C1

22p

ICS840004