858020AK

9

REV. A DECEMBER 10, 2007

ICS858020

Figure 3 shows a schematic example of the ICS858020. This

schematic provides examples of input and output handling.The

ICS858020 input has built-in 50

Ω termination resistors.The in-

put can directly accept various types of differential signal with-

out AC couple. If AC couple termination is used, the ICS858020

also provides VREF_AC pin for proper offset level after the AC

Zo = 50

Zo = 50

3.3V

Zo = 50

U1

ICS858020

1

2

3

4

9

10

11

12

IN

VT

VREF_AC

nIN

nQ2

Q2

nQ1

Q1

Zo = 50

100 Ohm Dif f erential

+

-

LVPECL

R2

100

R4

100

3.3V

C1

0.1u

Zo = 50

3.3V

C2

0.1u

2.5V

R1

100

C6

C5

Zo = 50

R3

100

3.3V

100 Ohm Dif f erential

+

-

couple. This example shows the ICS858020 input driven by a

2.5V LVPECL driver with AC couple. The ICS858020 outputs

are CML driver with built-in 50

Ω pull up resistors. In this ex-

ample, we assume the traces are long transmission line and the

receiver is high input impedance without built-in matched load.

An external 100

Ω resistor across the receiver input is required.