HFBR-0566 Avago Technologies US Inc., HFBR-0566 Datasheet - Page 6

• Manufacturer Part Number: HFBR-0566
• Description: Fiber Optic Development Tools MT-RJ 622Mb/s Fast E Evaluation Kit
• Manufacturer: Avago Technologies US Inc.

Specifications of HFBR-0566

• Description/function: Fiber Optic Kit
• For Use With/related Products: HFBR-5908E, HFCT-5908E
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Application Information
The Applications Engineering Group at Avago is available
to assist you with technical understanding and design
trade-offs associated with these transceivers. You can
contact them through your Avago sales representative.
The following information is provided to answer some of
the most common questions about the use of the parts.
Optical Power Budget and Link Penalties
The worst-case Optical Power Budget (OPB) in dB for a
fiber-optic link is determined by the difference between
the minimum transmitter output optical power (dBm avg)
and the lowest receiver sensitivity (dBm avg). This OPB
provides the necessary optical signal range to establish a
working fiber-optic link. The OPB is allocated for the fiber-
optic cable length and the corre-sponding link penalties.
For proper link performance, all penalties that affect the
link performance must be accounted for within the link
optical power budget.
Figure 5. +3.3 V Transceiver Interface with +3.3 V LVPECL Device
6
Note: C1 = C2 = C3 = 10 nF or 100 nF
T
R
X
X
TTL T
X
D
IS
10
1
V
CC
9
2
(+3.3 V)
8
3
130
7
4
82
130
5
6
V
130
CC
(+3.3 V)
130
82
C2
C1
1 µH
1 µH
100 nF
100 nF
C3
V
CC
Z = 50
Z = 50
Z = 50
(+3.3 V)
10 µF
Electrical and Mechanical Interface
Recommended Circuit
Figure 5 shows the recommended interface for deploying
the Avago transceiver in a +3.3 V system. Also present are
power supply filtering arrangements which comply with
the recommendations of the small form factor multisource
agreement. This configuration ensures noise rejection
compatibility between transceivers from various vendors.
Data Line Interconnections
Avago’s HFBR/HFCT-5908E fiber-optic transceiver is
designed to couple to +3.3 V PECL signals. Figure 5 depicts
the circuit options. The transmitter driver circuit regulates
the output optical power. The regulated light output will
maintain a constant output optical power provided the
data pattern is reasonably balanced in duty factor. If the
data duty factor has long, continuous state times (low or
high data duty factor), then the output optical power will
gradually change its average output optical power level
to its preset value.
Z = 50
Z = 50
100 nF
100 nF
10 k
V
V
CC
CC
130
(+3.3 V)
(+3.3 V)
130
82
V
130
CC
(+3.3 V)
130
82
TD-
TD+
RD+
RD-
SD
TTL
V
PHY DEVICE
CC
LVPECL
(+3.3 V)
LVPECL
V
CC
(+3.3 V)