HFBR-0528 Avago Technologies US Inc., HFBR-0528 Datasheet - Page 8

• Manufacturer Part Number: HFBR-0528
• Description: KIT EVAL FIBER OPTIC 10MBD
• Manufacturer: Avago Technologies US Inc.

Specifications of HFBR-0528

• Main Purpose: Interface, Fiber Optics
• Embedded: No
• Utilized Ic / Part: HFBR-1528, HFBR-2528
• Primary Attributes: 10MBd, Communication up to 50m using 1mm POF
• Secondary Attributes: Crimpless Connectors
• Silicon Core Number: HFBR-1528, HFBR-2528
• Kit Contents: TX/RX Mods, Cable, Pol Kit, SW, Pwr. Sup
• Silicon Family Name: Versatile Link
• Features: Fiber Optic Transmitter And Receiver
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 516-2144; HFBR-0528

Figure 13. Typical Normalized Spectral Attenuation of 1 mm POF.
Because of the complexity of the receiver circuit IC, a
detailed discussion about sensitivity temperature drift is
beyond the scope of this application note. Drift effects
are specified in the product data sheet and one should
not be concerned about them.
1.4. Reliability Considerations
The service lifetime of the fiber-optic link is, however,
quite often a concern. One can separate link reliability
into transmitter, receiver, connector and fiber reliabil-
ity. HCS fibers are known to be very stable under harsh
ambient conditions and have been qualified for 30-year
lifetimes. POFs are estimated for up to 20-year lifetimes.
Short-term and long-term bend radius, tensile load, flex-
ing, as well as the mechanical properties of the connec-
tors are specified in the cable data sheet
discussion about fiber
beyond the scope of this application note.
More of a concern is the useful lifetime of short-wave-
length LED transmitters, which must be taken into ac-
count in power budget calculations. It can be assumed
that the receiver sensitivity will not change over time.
The transmitter light output reduction is a function of
junction temperature, drive current, and endurance
time. The useful lifetime of the LED transmitter is typi-
cally defined when the initial light output is reduced
by 3 dB. Reliability tests of the HFBR-528Z transmitter
project a median useful life of 9 years at -3dB, 85°C, 50 %
duty cycle, and forward current equal to 60 mA. There-
fore, the optical power budget must be decreased by
the expected reduction in light output at the end-of-life
specification. More detailed information can be found in
the reliability data sheet
8
-0.2
-0.4
1.0
0.8
0.6
0.4
0.2
0
640
NORMALIZED AT 660 nm
650
WAVELENGTH (nm)
650
[,2]
[6]
.
and connector
670
680
[8]
[8]
reliability is
. A detailed
Table III/1: Projected useful life for various temperatures, where
end of life is defined as a 50% drop (-3dB) in light output.
1.5. Connector Loss
Connector coupling losses at the transmitter and receiv-
er are already included in the data sheet specifications.
Connector coupling losses due to connections through
bulkhead adapters need to be determined. The follow-
ing table shows the minimum and maximum insertion
loss spec-ifications for Avago Technologies'  mm POF
bulkhead connections. As the number of bulkhead con-
nections increases, the range of losses increases, as does
the magnitude of the losses. Coupling loss char-acteriza-
tion of special bulkhead connectors for the 200 µm HCS
fiber was not completed when this application note was
printed.
Table III/2. Feed Through Loss Specifications.
1.6. Coupling Loss
If light from a larger-core fiber is coupled into a smaller-
core fiber, a significant loss of optical power can be mea-
sured. The loss is a function of the difference in area (d)
and the numerical aperture (NA), and is expressed by the
following formula:
Equation III/5:
d: Emitting fiber diameter
d2: Receiving fiber diameter
NA: Numerical Aperture emitting fiber
NA2: Numerical Aperture receiving fiber
Light from a smaller core fiber will be coupled into a
larger core fiber without area and NA losses.
Part
HFBR-
45X5Z
IL(dB) = 20
l(max) =
No.
P (T) = P (25) –
P (dBm) = 10
I
l(min) =
F
l =
V (T) = V (25)
R1 =
50%
T
[mA]
DC
60
60
60
60
F
P (min)
T
vp =
Vcc - Vce - V
 mm
Fiber
POF
[°C]
Size
T
•
85
70
55
40
T
Pt(max) - P
−
P (min) - P
I
A
F
log
F
•
T
c
n
P
log
in m/s
RL, min
a(min)
a(max)
Median
Min.
Loss
−
Life [y]
d1
d2
F
Useful
0.7
dB
7
33
68
P(mW)
9
+ 20
−
a(max)
∆
∆
RL, max
∆
∆
RL, min
P
V
IL(max)
T
T
Loss
Typ. Max.
T
F
•
.5
dB
•
log
• (T – 25)
(T – 25)
Survival
(in m)
Life [y]
- IL - OPM
90%
−
5
32
4
8
Loss
OPM
2.8
dB
NA2
NA1
(m)