840011AG

www.icst.com/products/hiperclocks.html

REV. A OCTOBER 15, 2004

7

Integrated

Circuit

Systems, Inc.

ICS840011

Figure 3A shows a schematic example of the ICS840011. An

example of LVCMOS termination is shown in this schematic.

Additional LVCMOS termination approaches are shown in the

LVCMOS Termination Application Note. In this example, an 18pF

parallel resonant 26.5625MHz crystal is used for generating

106.25MHz output frequency. The C1 = 27pF and C2 = 33pF

are recommended for frequency accuracy. For different board

layout, the C1 and C2 values may be slightly adjusted for opti-

mizing frequency accuracy.

Figure 3B shows an example of P.C. board layout. The crystal

X1 footprint in this example allows either surface mount (HC49S)

or through hole (HC49) package. C3 is 0805. C1 and C2 are

0402. Other resistors and capacitors are 0603. This layout as-

sumes that the board has clean analog power and ground planes.

R3

43

Zo = 50 Ohm

R2

10

OE

C5

0.1u

VDD

U1

ICS840011

1

2

3

4

8

7

6

5

VDDA

OE

XTAL_OUT

XTAL_IN

VDD

Q0

GND

NC

C4

0.1u

C3

10uF

C1

27pF

C2

33pF

VDD=3.3V

X1

VDDA

VDD

Q

LVCMOS