HFBR-53D5FM HP [Agilent(Hewlett-Packard)], HFBR-53D5FM Datasheet - Page 5

• Manufacturer Part Number: HFBR-53D5FM
• Description: 1 x 9 Fiber Optic Transceivers for Gigabit Ethernet
• Manufacturer: HP [Agilent(Hewlett-Packard)]

intrinsically eye safe and does not
require shut down circuitry.
Signal Detect
The Signal Detect circuit provides
a deasserted output signal that
implies the link is open or the
transmitter is OFF as defined by
the Gigabit Ethernet specification
IEEE 802.3z, Table 38.1. The
Signal Detect threshold is set to
transition from a high to low state
between the minimum receiver
input optional power and –30 dBm
avg. input optical power
indicating a definite optical fault
(e.g. unplugged connector for the
receiver or transmitter, broken
fiber, or failed far-end transmitter
or data source). A Signal Detect
indicating a working link is
functional when receiving
encoded 8B/10B characters. The
Signal Detect does not detect
receiver data error or error-rate.
Data errors are determined by
Signal processing following the
transceiver.
Electromagnetic
Interference (EMI)
One of a circuit board designer’s
foremost concerns is the control
of electromagnetic emissions
from electronic equipment.
Success in controlling generated
Electromagnetic Interference
(EMI) enables the designer to
pass a governmental agency’s
EMI regulatory standard; and
more importantly, it reduces the
possibility of interference to
neighboring equipment. There
are three options available for the
HFBR-53D5 and two options for
the HFCT-53D5 with regard to
EMI shielding which provide the
designer with a means to achieve
good EMI performance. The EMI
performance of an enclosure
using these transceivers is
dependent on the chassis design.
Agilent encourages using
standard RF suppression
practices and avoiding poorly
EMI-sealed enclosures.
The first configuration is a
standard HFBR-53D5 fiber-optic
transceiver that has no external
EMI shield. This unit is for
applications where EMI is either
not an issue for the designer, or
the unit resides completely inside
a shielded enclosure, or the
module is used in low density,
extremely quiet applications. The
HFCT-53D5 is not available for
use without an external shield.
The second configuration, option
EM, is for EMI shielding
applications where the position of
the transceiver module will
extend outside the equipment
enclosure. The metallized plastic
package and integral external
metal shield of the transceiver
helps locally to terminate EM
fields to the chassis to prevent
their emissions outside the
enclosure. This metal shield
contacts the panel or enclosure
on the inside of the aperture on
all but the bottom side of the
shield and provides a good RF
connection to the panel. This
option can accommodate various
panel or enclosure thickness, i.e.,
.04 in. min. to 0.10 in. max. The
reference plane for this panel
thickness variation is from the
front surface of the panel or
enclosure. The recommended
length for protruding the
HFBR/HFCT-53D5EM transceiver
beyond the front surface of the
panel or enclosure is 0.25 in.
With this option, there is
flexibility of positioning the
module to fit the specific need of
the enclosure design. (See Figure
6 for the mechanical drawing
dimensions of this shield.)
5
The third configuration, option
FM, is for applications that are
designed to have a flush
mounting of the module with
respect to the front of the panel
or enclosure. The flush-mount
design accommodates a large
variety of panel thickness, i.e.,
0.04 in. min. to 0.10 in. max.
Note the reference plane for the
flush-mount design is the interior
side of the panel or enclosure.
The recommended distance from
the centerline of the transceiver
front solder posts to the inside
wall of the panel is 0.55 in. This
option contacts the inside panel
or enclosure wall on all four sides
of this metal shield. See Figure 8
for the mechanical drawing
dimensions of this shield.
The two metallized designs are
comparable in their shielding
effectiveness. Both design
options connect only to the
equipment chassis and not to the
signal or logic ground of the
circuit board within the
equipment closure. The front
panel aperture dimensions are
recommended in Figures 7 and 9.
When layout of the printed circuit
board is done to incorporate
these metal-shielded transceivers,
keep the area on the printed
circuit board directly under the
metal shield free of any
components and circuit board
traces. For additional EMI
performance advantage, use
duplex SC fiber-optic connectors
that have low metal content
inside them. This lowers the
ability of the metal fiber-optic
connectors to couple EMI out
through the aperture of the panel
or enclosure.
Evaluation Kit
To help you in your preliminary
transceiver evaluation, Agilent
offers a 1250 MBd Gigabit