843011CG

www.icst.com/products/hiperclocks.html

REV. A JANUARY 25, 2006

6

Integrated

Circuit

Systems, Inc.

ICS843011C

PRELIMINARY

Figure 3A shows a schematic example of the ICS843011C.

An example of LVEPCL termination is shown in this sche-

matic. Additional LVPECL termination approaches are shown

in the LVPECL Termination Application Note. In this example,

an 18 pF 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 optimizing frequency accuracy.

Figure 3B shows an example of ICS843011C P.C. board lay-

out. The crystal X1 footprint shown in this example allows

installation of either surface mount HC49S or through-hole

HC49 package. The footprints of other components in this

example are listed in the Table 6. There should be at least one

decoupling capacitor per power pin. The decoupling capaci-

tors should be located as close as possible to the power pins.

The layout assumes that the board has clean analog power

ground plane.

e

c

n

e

r

e

f

e

Re

z

i

S

2

C

,

1

C2

0

4

0

3

C5

0

8

0

5

C

,

4

C3

0

6

0

2

R3

0

6

0

t

n

e

n

o

p

m

o

c

s

t

s

il

,

6

e

l

b

a

T

:

E

T

O

N

.

e

l

p

m

a

x

e

t

u

o

y

a

l

s

i

h

t

n

i

n

w

o

h

s

s

e

z

i

s

R5

50

Zo = 50 Ohm

C4

0.1u

C2

33pF

XTAL_IN

Q

nQ

18pF

VCCA

R5

133

R2

10

Zo = 50 Ohm

C5

0.1u

R6

50

Zo = 50 Ohm

R4

82.5

+

-

Optional

Y-Termination

Q

XTAL_OUT

X1

26.5625MHz

Zo = 50 Ohm

nQ

VCC

VCC

C1

27pF

+

-

R7

50

U2

843011C

1

2

3

4

8

7

6

5

VCCA

VEE

XTAL_OUT

XTAL_IN

VCC

Q

nQ

nc

R6

82.5

C3

10uF

VCC

R3

133