6

Agere Systems Inc.

R480-Type Lightwave Receiver with CML Data Output

Data Sheet, Rev. 1

for up to 2.488 Gbits/s Applications

September 2001

PWB Layout Guidelines

s

The data outputs are designed to drive 50

Ω loads.

s

Data output traces must be controlled-impedance lines and the termination impedance must match the line

impedance. Avoid 90

° bends in the traces. Paired lines (i.e., DATA and DATA) must be equal in length.

s

Data output lines should be as short and straight as possible and should be shielded from noise sources to pre-

vent noise from feeding back into the receiver.

s

Use high-quality multilayer printed-wiring boards. A ground plane should occupy the area directly beneath the

receiver.

1-934(C)d

Note 1: Data outputs must be ac-coupled on customer board. Use a 0.1

µF chip capacitor with a low ESR. For optimum receiver performance,

both data outputs must be terminated in equivalent loads, even if one of the outputs is not being used.

Note 2: The 0.1

the appropriate power supply leads and should provide a low-inductance path to the ground plane.

Figure 1. Biasing and Interfacing to the R480-Type 2.5 Gbits/s Receiver

8, 22

10

11

23

DATA

DATA

OILV

50

Ω TRANSMISSION

LOS (FLAG)

4, 7, 9, 12,

3

2.2

µF

15

µF

+5 V

0.1

µF

50

Ω

+

14—17, 19, 20

LINE (2X)

1

µH

0.1

µF

NOTE 2

NOTE 1