4

Package

The overall package concept

for the device consists of the

following basic elements; two

optical subassemblies, two

electrical subassemblies and

the housing as illustrated in

the block diagram in Figure 3.

The package outline drawing

and pin out are shown in

Figures 4 and 5. The details of

this package outline and pin

out are compliant with the

multisource definition of the 2

x 10 DIP.

A metallic nose clip provides

connection to chassis ground

for both EMI and thermal

dissipation.

The electrical subassemblies

consist of high volume

multilayer printed circuit

boards on which the IC and

various surface-mounted

passive circuit elements are

attached.

The receiver electrical

subassembly includes an

internal shield for the

electrical and optical

subassembly to ensure high

immunity to external EMI

fields.

The optical subassemblies are

each attached to their

respective transmit or receive

electrical subassemblies. These

two units are then fitted

within the outer housing of the

transceiver that is molded of

filled nonconductive plastic to

provide mechanical strength.

The housing is then encased

with a metal EMI protective

shield. The case is signal

ground and we recommend

soldering the four ground tabs

to host card signal ground.

The pcb’s for the two electrical

subassemblies both carry the

signal pins that exit from the

bottom of the transceiver. The

solder posts are fastened into

the molding of the device and

are designed to provide the

mechanical strength required

to withstand the loads

imposed on the transceiver by

mating with the LC

connectored fiber cables.

Although they are not

connected electrically to the

transceiver, it is recommended

to connect them to chassis

ground.

Figure 3. Block Diagram

DATA OUT

SIGNAL

DETECT

DATA IN

DATA IN

Tx DISABLE

B

B

P

P

QUANTIZER IC

LASER DRIVER

AND CONTROL

CIRCUIT

PIN PHOTODIODE

PREAMPLIFIER

SUBASSEMBLY

LASER

OPTICAL

SUBASSEMBLY

DATA OUT

LC

RECEPTACLE

R

T

R

T

PHOTO DETECTOR

BIAS

LASER BIAS

MONITORING

LASER DIODE

OUTPUT POWER

MONITORING

CASE

*

* NOSE CLIP PROVIDES CONNECTION TO CHASSIS GROUND FOR BOTH EMI AND THERMAL DISSIPATION.