HFBR-0571 Avago Technologies US Inc., HFBR-0571 Datasheet - Page 3

• Manufacturer Part Number: HFBR-0571
• Description: Fiber Optics, Evaluation Kit
• Manufacturer: Avago Technologies US Inc.

Specifications of HFBR-0571

• Silicon Core Number: HFBR-5710LP, HFBR-5730LP, HFCT-5710LP
• Kit Contents: Evaluation PC Board, Associated Technical Literature
• Development Tool Type: Hardware / Software - Eval/Demo Board
• Main Purpose: Interface, Ethernet
• Embedded: No
• Utilized Ic / Part: HFCT-57xx, HFBR-57xx
• Primary Attributes: SFP Gigabit Ethernet and Fibre Channel Applications
• Secondary Attributes: Small Form Factor Pluggable (SFP)
• Tool / Board Applications: Optical Transceivers
• Rohs Compliant: Yes
• Description/function: Fiber Optic Kit
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• For Use With/related Products: HFBR-57x, HFCT-57x
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant, Contains lead / RoHS non-compliant

Transmitter Section
The transmitter section includes 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 converts differential
logic signals into an analog laser diode drive current. This
Tx driver circuit regulates the optical power at a constant
level provided the data pattern is DC balanced (8B10B
code for example).
Tx Disable
The HFBR-5701L accepts a transmit disable control signal
input which shuts down the transmitter. A high signal
implements this function while a low signal allows normal
laser operation. In the event of a fault (e.g., eye safety
circuit activated), cycling this control signal resets the
module as depicted in Figure 6.
Eye Safety Circuit
The HFBR-5701L provides Class 1 eye safety by design and
has been tested for compliance with the requirements
listed in Table 1. The eye safety circuit continuously
monitors optical output power levels and will disable the
transmitter and assert a TX_FAULT signal upon detecting
an unsafe condition. Such unsafe conditions can be created
by inputs from the host board (Vcc fluxuation, unbalanced
code) or faults within the module.
Receiver Section
The receiver section includes the Receiver Optical Subas-
sembly (ROSA) and amplification/quantization circuitry.
The ROSA, containing a PIN photodiode and custom trans-
impedance preamplifier, is located at the optical interface
and mates with the LC optical connector. The ROSA is
mated to a custom IC that provides post-amplification
and quantization. Also included is a Loss Of Signal (LOS)
detection circuit.
Figure 3. MSA required power supply filter.
3
SFP MODULE
V
V
CC
CC
R
T
0.1 µF
0.1 µF
HOST BOARD
10 µF
1 µH
1 µH
0.1 µF
10 µF
Loss of Signal
The Loss Of Signal (LOS) output indicates an unusable
optical input power level. A high LOS output signal
indicates a loss of signal while a low LOS output signal
indicates normal operation. The Loss Of Signal thresholds
are set to indicate a definite optical fault has occurred (e.g.,
disconnected or broken fiber connection to receiver, failed
transmitter, etc.).
Functional I/O
The HFBR-5701L accepts industry standard differential
signals such as LVPECL and CML within the scope of the
SFP MSA. To simplify board requirements, transmitter bias
resistors and coupling capacitors are incorporated into
the transceiver module. The module is “ac-coupled” and
internally terminated.
Figure 4 illustrates a recommended interface circuit to
link the HFBR-5701L to the supporting Physical Layer in-
tegrated circuits.
Timing diagrams for the MSA compliant control signals
implemented in this module are depicted in Figure 6.
Required Host Board Components
The MSA power supply noise rejection filter is required on
the host PCB to meet data sheet performance. The MSA
filter incorporates an inductor which should be rated 400
mADC and
should not be replaced with a ferrite. The required filter is
illustrated in Figure 3.
The MSA also specifies that 4.7 K to 10 KΩ pull-up resistors
for TX_FAULT, LOS, and MOD_DEF0,1,2 are required on the
host PCB.
3.3 V
1 Ω series resistance or better. It