8442AYI

www.icst.com/products/hiperclocks.html

REV. C MAY 10, 2005

9

Integrated

Circuit

Systems, Inc.

ICS8442I

A crystal can be characterized for either series or parallel mode

operation. The ICS8442I has a built-in crystal oscillator circuit.

This interface can accept either a series or parallel crystal without

additional components and generate frequencies with accuracy

suitable for most applications. Additional accuracy can be

achieved by adding two small capacitors C1 and C2 as shown in

Figure 3. Typical results using parallel 18pF crystals are shown

in Table 10.

A general LVDS interface is shown in

Figure 4. In a 100

Ω differ-

ential transmission line environment, LVDS drivers require a

matched load termination of 100

Ω across near the receiver in-

put. For a multiple LVDS outputs buffer, if only partial outputs

are used, it is recommended to terminate the un-used outputs.

100

Ω

Ω

Ω

Ω

Ω Differential Transmission Line

The schematic below is recommended for applications using the

÷1 output configuration for improving the differential duty cycle.

3.3V

3.3V

LVDS_DRIVER

R1

100

HiPerClockS

Zo = 50 Ohm

Zo = 50 Ohm

nCLK

CLK

R1

100

C1

.1uf

Vcc = 3.3V

R3

800

LVDS Driv er

R2

1.3k

Zo = 50

R4

1.3k

C2

.1uf

Receiv er_dif

+

-

Zo = 50

R5

800

C1

18p

X1

18pF Parallel Crystal

C2

22p

XTAL_IN

XTAL_OUT