uses a low cost 800 nm AlGaAs
LED. These LEDs are packaged in
the optical subassembly portion
of the transmitter section. They
are driven by a custom silicon IC
which converts differential PECL
logic signals, ECL referenced
(shifted) to a +5 Volt supply, into
an analog LED drive current.
Receiver Sections
The receiver sections of the
HFBR-5204 and HFBR-5205
series utilize InGaAs PIN photo-
diodes coupled to a custom
silicon transimpedance preampli-
fier IC. The HFBR-5203 series
uses the same preamplifier IC in
conjunction with an inexpensive
silicon PIN photodiode. These are
packaged in the optical subassem-
bly portion of the receiver.
These PIN/preamplifier combina-
tions are coupled to a custom
quantizer IC which provides the
final pulse shaping for the logic
output and the Signal Detect
function. The data output is
differential. The signal detect
output is single-ended. Both data
and signal detect outputs are
PECL compatible, ECL referenced
(shifted) to a +5 volt power
supply.
Package
The overall package concept for
the HP transceivers consists of
three basic elements; the two
optical subassemblies, an
electrical subassembly, and the
housing as illustrated in the block
diagrams in Figure 1 and
Figure 1a.
The package outline drawing and
pin out are shown in Figures 2,
2a, and 3. The details of this
package outline and pin out are
compliant with the multisource
definition of the 1x9 SIP. The low
profile of the Hewlett-Packard
108
transceiver design complies with
the maximum height allowed for
the duplex SC connector over the
entire length of the package.
The optical subassemblies utilize
a high volume assembly process
together with low cost lens
elements which result in a cost
effective building block.
The electrical subassembly con-
sists of a high volume multilayer
printed circuit board on which the
IC chips and various surface-
mounted passive circuit elements
are attached.
The package includes internal
shields for the electrical and
optical subassemblies to insure
low EMI emissions and high
immunity to external EMI fields.
The outer housing including the
duplex SC connector or the
duplex ST ports is molded of filled
non-conductive plastic to provide
mechanical strength and electrical
isolation. The solder posts of the
Hewlett-Packard design are
isolated from the circuit design of
the transceiver and do not require
connection to a ground plane on
the circuit board.
The transceiver is attached to a
printed circuit board with the nine
signal pins and the two solder
posts which exit the bottom of the
housing. The two solder posts
provide the primary mechanical
strength to withstand the loads
imposed on the transceiver by
mating with the duplex or simplex
SC or ST connectored fiber
cables.
Note: The “T” in the product
numbers indicates a transceiver
with a duplex ST connector
receptacle. Product numbers
without a “T” indicate transceivers
with a duplex SC connector
receptacle.
Application Information
The Applications Engineering
group in the Hewlett-Packard
Optical Communication Division
is available to assist you with the
technical understanding and
design trade-offs associated with
these transceivers. You can con-
tact them through your Hewlett-
Packard sales representative.
ELECTRICAL SUBASSEMBLY
DIFFERENTIAL
DATA OUT
SINGLE-ENDED
SIGNAL
DETECT OUT
QUANTIZER IC
PREAMP IC
DUPLEX SC
RECEPTACLE
PIN PHOTODIODE
OPTICAL
SUBASSEMBLIES
DIFFERENTIAL
DATA IN
DRIVER IC
LED
TOP VIEW
Figure 1. Block Diagram.
AGILENT [ AGILENT TECHNOLOGIES, LTD. ]
