843002AGI

www.icst.com/products/hiperclocks.html

REV. A JANUARY 4, 2006

11

Integrated

Circuit

Systems, Inc.

ICS843002I

Figure 5A shows a schematic example of the ICS843002I. An

example of LVEPCL termination is shown in this schematic.

Additional LVPECL termination approaches are shown in the

LVPECL Termination Application Note. In this example, an

18pF parallel resonant 26.5625MHz crystal is used. The

C1=27pF and C2=33pF are recommended for frequency ac-

curacy. For different board layout, the C1 and C2 may be

slightly adjusted for optimizing frequency accuracy.

Figure 5B shows an example of ICS843002I P.C. board layout.

The crystal X1 footprint shown in this example allows installa-

tion of either surface mount HC49S or through-hole HC49 pack-

age.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 capacitors 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

8

C

,

7

C

,

6

C

,

5

C

,

4

C3

0

6

0

2

R3

0

6

0

s

e

z

i

s

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

ICS843002I

C7

0.1u

C1

27pF

Zo = 50 Ohm

C4

0.01u

C9

0.1u

To Logic

Input

pins

VCC

U1

ICS843002i

R9

50

Logic Control Input Examples

VCC

Set Logic

Input to

'0'

R3

133

Set Logic

Input to

'1'

R8

50

Zo = 50 Ohm

RU2

Not Install

Zo = 50 Ohm

R2

10

C6

0.1u

R4

82.5

R7

50

R5

133

C3

10uF

VCCO=3.3V

+

-

Optional Termination

RD1

Not Install

VCC

VCCO

VCC=3.3V

+

-

VCCA

3.3V

RD2

1K

To Logic

Input

pins

VCCO

C2

33pF

C8

0.1u

RU1

1K

Zo = 50 Ohm

VCC

18pF

X1

26.5625MHz

R6

82.5