2
FDDI PMD standard. Likewise,
the Fast Ethernet Alliance defines
the Physical Layer for the 100
Base-FX Version of IEEE 802.3u
to be the FDDI PMD standard.
differential. Also, both Data and
Signal Detect outputs are PECL
compatible, ECL referenced
Each transceiver package
includes internal shields for the
electrical and optical subassem-
blies to ensure low EMI emissions
and high immunity to external
EMI fields.
(shifted) to a +5 V power supply.
Package
Agilent also provides several
other FDDI products compliant
with the FDDI Low Cost Fiber
(LCF) -PMD and Single Mode
(SM) -PMD standards. These
products are available with ST,
SC, and FC connector styles.
They are available in the 1x9
transceiver and 14- and 16-pin
transmitter/receiver package
styles for those designs that
require these alternate
The overall package concept for
the Agilent transceiver consists of
the following basic elements: two
optical subassemblies, an
electrical subassembly, and the
housing with full compliance to
the FDDI PMD standard. A block
diagram is illustrated in Figure 1.
The outer housings including the
MIC receptacles are molded of
filled non-conductive plastic to
provide mechanical strength and
electrical isolation. The solder
posts of each package design are
isolated from the circuit design of
the transceiver and do not require
connection to a ground plane on
the circuit board.
The package outline drawings
and pin-outs are shown in Figures
2 and 3. These are compliant with
the industry standard 2x11 and
1x13 pin configurations.
configurations. Contact your
Agilent sales representative for
information on these alternative
FDDI products.
Each transceiver is attached to its
printed circuit boards with the
2x11 or 1x13 signal pins and the
solder posts which exit the
bottom of the housing. The solder
posts provide the primary
mechanical strength to withstand
the loads imposed on the
transceiver when mating with
MIC-connectored fiber cables.
The optical subassemblies utilize
a high-volume assembly process
together with low-cost lens
elements which result in a cost-
effective building block.
Transmitter Section
The transmitter section of the
HFBR-511X Series utilizes a 1300
nm surface emitting InGaAsP
LED. The LED is packaged in the
optical subassembly portion of
the transmitter section. It is dc-
coupled to a custom IC which
converts differential-input, PECL
logic signals, ECL referenced
(shifted) to a +5 V power supply,
into an analog LED drive current.
The electrical subassemblies
consist of a high-volume, multi-
layer printed circuit board on
which the IC chips and various
surface-mounted passive circuit
elements are attached.
Application Information
The Applications Engineering
group of the Optical Communica-
tion Division is available to assist
you with the technical under-
Receiver Section
The receiver section of the
HFBR-511X Series utilizes an
InGaAs PIN photodiode coupled
to a custom silicon transimped-
ance preamplifier IC. They are
packaged in the optical sub-
assembly portion of the receiver.
ELECTRICAL SUBASSEMBLY
DIFFERENTIAL
DATA OUT
DIFFERENTIAL
SIGNAL
PIN PHOTODIODE
OPTICAL
QUANTIZER IC
DETECT OUT
PREAMP
IC
TOP VIEW
SUBASSEMBLIES
The PIN/preamplifier combina-
tion is ac-coupled to a custom
quantizer IC which provides the
final pulse shaping for the logic
output and the Signal Detect
function. Both the Data and
Signal Detect outputs are
DIFFERENTIAL
DATA IN
LED
DRIVER IC
Figure 1. HFBR-5111/-5112/-5113 Block Diagram.