HFCT-5005 Avago Technologies US Inc., HFCT-5005 Datasheet - Page 2

• Manufacturer Part Number: HFCT-5005
• Description: Fiber Optics, Evaluation Kit
• Manufacturer: Avago Technologies US Inc.

Specifications of HFCT-5005

• Silicon Core Number: HFBR-5911L, HFCT-5911ATL
• Kit Contents: LC Evaluation Board, Associated Technical Literature
• Main Purpose: Interface, Fiber Optics
• Embedded: No
• Utilized Ic / Part: HFCT-59xx, HFBR-59xx
• Primary Attributes: Singlemode OC-48 SFF PTH Transceiver Applications
• Secondary Attributes: Short or Intermediate Reach
• Description/function: Fiber Optic Kit
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With/related Products: HFCT-59x
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Contains lead / RoHS non-compliant

Overview
Avago Technologies’ HFBR-5911L/AL optical transceiver
supports high-speed serial links over multimode optical
fiber at signaling rates of up to 1.25 Gb/s. Compliant
with the Small Form Factor (SFF) Multi Source
Agreement (MSA) for 2 x 5 pin LC Duplex transceivers
and IEEE 802.3 specification for Gigabit Ethernet (GbE)
links (1000BASE-SX), the part is interoperable and
interchangeable with other conformant devices.
Supported Gigabit Ethernet link lengths are described
in Table 1, but the transceiver can also be used for
other high-speed serial applications, such as iSCSI.
The SFF package of the HFBR-5911L/AL allows
designers of Gigabit Ethernet networking equipment
to maximize their use of available board space. The
footprint of the HFBR-5911L/AL is significantly smaller
than those of other GbE transceivers formats - 25%
smaller than SFP cage assemblies, 30% smaller than
traditional 1 x 9 transceivers and 70% smaller than GBIC
rail assemblies. The HFBR-5911L/AL trace keep-out area
is less than 10% as large as that required by SFP
transceivers. For applications not requiring hot-
pluggability, the HFBR-5911L/AL offers a more space-
efficient package without the additional cost and
complexity imposed by pluggable architecture.
Module Diagrams
The major functional components of the HFBR-5911L/
AL are illustrated in Figure 2 page 9. The external
configuration of the transceiver is depicted in Figure 3
page 10 while the host board and front panel layouts
defined by the SFF MSA are shown in Figure 4, page
11.
Transmitter Section
The transmitter section consists of the Transmitter
Optical Subassembly (TOSA) and laser driver circuitry.
The TOSA, containing an 850 nm VCSEL (Vertical Cavity
Surface Emitting Laser) light source, is located at the
optical interface and mates with the LC optical
connector. The TOSA is driven by a custom IC which
uses the incoming differential PECL logic signals to
modulate the laser diode drive current. This Tx laser
driver circuit regulates the optical output power at a
constant level provided that the incoming data pattern
is dc balanced (8B10B code for example).
2
Tx_Disable
The HFBR-5911L/AL accepts a TTL transmit disable
control signal input which shuts down the transmitter.
A high signal implements this function while a low
signal allows normal transceiver operation. In the event
of a fault (e.g., eye safety circuit activated), cycling this
control signal resets the module as depicted in Figure
5 page 12. A pull-down resistor enables the laser if the
line is not connected on the host board.
Host systems should allow a 10 ms interval between
successive assertions of this control signal.
Eye Safety Circuit
The HFBR-5911L/AL provides Class 1 eye safety by
design and has been tested for compliance with the
requirements listed in Table 11. The eye safety circuit
continuously monitors optical output power levels and
will disable the transmitter upon detecting an unsafe
condition. Such unsafe conditions can be due to inputs
from the host board (V
or faults within the transceiver.
Receiver Section
The receiver section includes the Receiver Optical
Subassembly (ROSA) and the amplification/quantization
circuitry. The ROSA, containing a PIN photodiode and
custom transimpedance preamplifier, is located at the
optical interface and mates with the LC optical
connector. The ROSA output is fed to a custom IC that
provides post-amplification and quantization.
Signal Detect
The post-amplification/quantizer IC also includes
transition detection circuitry that monitors the ac level
of the incoming optical signal and provides a TTL status
signal to the host. An adequate optical input results in
a high output while a low Signal Detect output indicates
an unusable optical input. The Signal Detect thresholds
are set so that a low output indicates a definite optical
fault has occurred (e.g., disconnected or broken fiber
connection to receiver, failed transmitter, etc.).
CC
fluctuation, unbalanced code)