The component is designed to provide cost effective, high
performance fiber optic communication links for infor-
mation systems and industrial applications with link dis-
tances of up to 2 km. The receivers are directly compatible
with popular “industry-standard” connectors: ST and SMA.
They are designed for use with 50/125 μm, 62.5/125 μm,
and 200 μm multimode fiber.
Features
•
RoHS-compliant
•
Work with Avago HFBR-14xxZ (820nm LED) transmitter
•
Data transmission at signal rates from DC up to 50 MBd
•
Receiver: Integrated PIN diode and digitalizing IC with
CMOS/TTL output logic
•
Up to 2 km distance with Multimode Glass Fiber Cable
•
Operating temperature range of -40°C to +85°C
•
3.3 V and 5 V supply voltage operation
•
RSSI output
AFBR-24x8xZ Available Part Numbers
Part Number
AFBR-2408Z
AFBR-2418Z
AFBR-2418TZ
AFBR-2418MZ
Description
Receiver with SMA port
Receiver with ST port
Receiver with threaded ST port
Receiver with metal ST port
Applications
•
Optical transmission from DC up to 50 MBd
•
Industrial control and factory automation
•
High voltage isolation
•
Elimination of ground loops
Transmitter
HFBR-1414Z
HFBR-1414Z
HFBR-1414Z
Link Length
Data Rate
(MBd)
50
50
50
Max. Distance
(m)
900
2000
100
Fiber Size
(µm)
50/125
62.5/125
200
•
Reduces voltage transient susceptibility
•
Power substation automation
Note:
Verified with PRBS7 pattern using HFBR-1414Z transmitter, respecting its
worst case LOP conditions but assuming a proper fiber connection (direct
connection without add. connectors). Multiple or weak connections may
reduce the achievable link length.
Package and Handling Information
Package Information
The receiver is housed in a low-cost, dual-inline package
that is made of high strength, heat resistant, chemically
resistant, and UL 94V-O flame retardant ULTEM® plastic
(UL File #E121562). The receivers (suffix Z, TZ) are easily
identified by the dark grey color connector port. A metal
port option is also available (suffix MZ). The metal port op-
tion components have an internal electrical connection
between the metal port and the four grounding pins, as
shown in the package outline drawing. Signal ground is
separate from the four grounding pins to give flexibility in
connecting the port to signal or chassis ground. The pack-
age is designed for auto-insertion and wave soldering so
it is ideal for high volume production applications.
AFBR-24x8xZ Low-Cost 50 MBd Receiver
Description
The AFBR-24x8xZ fiber optic receiver is designed to oper-
ate with the Avago Technologies HFBR-14xxZ fiber optic
trans-mitters and multimode glass fiber cable. Consistent
coupling into the receiver is assured by the optical system
with lens. The receiver output is a digital CMOS/TTL signal.
The AFBR-24x8xZ receiver contains an IC with integrated
photodiode which directly converts the incoming opti-
cal signal to a digital output signal without the requisite
for additional external circuitry. Because of its integrated
design, the receiver has very high EMC resistance. A wide
receiver dynamic range and high sensitivity over tempera-
ture is achievable. The data rate typically goes from DC to
50MBd. A monitor (RSSI) output, which delivers an output
current proportional to the average incoming light power,
is available.
For an almost noise-free RSSI-signal smoothing compo-
nents are recommended. A capacitor in parallel to the re-
sistor on the RSSI output reduces potential high frequency
signal parts. The use of a single 100 nF capacitor for signal
smoothing is sufficient in most common applications, as
shown in the Recommended Receiver Circuitry section. If
this RSSI function is not required, the output pin can be
left floating. The RSSI-signal is derived from internal con-
trolling loops; therefore, the typical time constant of pure
RSSI output current without an external filter can be up to
1 ms. This time constant also depends on the actual aver-
age incoming light power.
Handling and Design Information
Each part comes with a protective port cap or plug cov-
ering the optics. These caps/plugs will vary by port style.
When soldering, it is advisable to leave the protective cap
on the unit to keep the optics clean. Good system per-
formance requires clean port optics and cable ferrules to
avoid obstructing the optical path. Clean compressed air
often is sufficient to remove particles of dirt; methanol on
a cotton swab also works well.
Absolute Maximum Ratings
Parameter
Storage Temperature
Operating Temperature
Supply Voltage
Maximum DC Output Current
Voltage at RSSI Output
Lead Soldering Cycle - Temp
Lead Soldering Cycle - Time
Symbol
T
S
T
A
V
CC
I
O
V
RSSI
T
SOLD
t
SOLD
Min
-40
-40
-0.3
-0.3
Max
+85
+85
5.5
10
V
CC
+0.3
260
10
Unit
°C
°C
V
mA
V
°C
s
Notes
1.6 mm below seating plane
2
Electrical/Optical Characteristics
-40° C to +85° C, 3.135 V < V
CC
< 5.25 V
Parameter
Optical Input Peak Power Range
(50 MBd proprietary)
Optical Spectrum Range
Data Rate
Supply Voltage
Supply Current
High Level Output Voltage
Low Level Output Voltage
Output Rise Time (10-90%)
Output Fall Time (90-10%)
Pulse Width Distortion
Pulse Width Distortion
1st to 3rd pulse
Propagation Delay
RSSI Output Responsivity
Voltage at RSSI Output
Symbol
P
IN-50
λ
IN
DR
V
CC
I
CC
V
OH
V
OL
t
R
t
F
PWD
PWD
INIT
t
RD
I
RSSI
/P
IN
V
RSSI
Min
-24
792
DC
3.135
Typ
[1]
Max
+1
Unit
dBm
nm
MBd
V
mA
V
V
ns
ns
ns
ns
ns
A/W
V
Condition
DR=50MBd
peak wavelength
Notes
2, 3, 4
820
865
50
5.25
20
2.4
V
CC
-0.3
0.2
30
VCC
0.4
5
5
R
L
=2kΩ
R
L
=2kΩ
R
L
=2kΩ
C
L
=10pF
C
L
=10pF
2, 4
2, 4
4, 8
6, 7, 8
8
5
-4
-5
+4
+8
40
0.72
0
V
CC
-1
Notes:
1. Typical data are at 25° C, V
CC
= 5.0 V.
2. In recommended receiver circuit, with an optical signal from the recommended transmitter circuit, transmitted via 62.5/125μm MM fiber.
3. Condition for sensitivity limit: Total Jitter ≤ 0.6 UI (unit intervals). The sensitivity was characterized by usage of transmitter HFBR-1414Z, an optical
attenuator for the particular power setting and a short piece of fiber (a few meters). The use of long fiber connections up to max. link length, as
specified in the table “Link Length” on page 1, may reduce the sensitivity.
4. Verified with a PRBS7 signal with mark ratio = ½ running at 50 MBd (in this case, the optical input average power levels are 3dB less than the
specified peak power levels).
5. Verified with an external resistor R
RSSI
=2 kΩ
6. If the data rate was below 1 MBd, the pulse width distortion would be equal to the pulse width distortion of the 1st to 3rd pulses for higher data
rates.
7. The threshold of the 1st pulse of a data sequence is difficult to adjust and therefore the pulse width distortion up to the 3rd pulse is higher than
for all other pulses (worst case for the 1st pulse). This strongly depends on the quality of the rising and falling edge of the optical input. The faster
the edges the smaller the pulse width variation. Furthermore lower data rates would result in the same issue as all the pulse become 1st pulses
8. The AFBR-24x8xZ is an inverting receiver, hence a logic high at the input (light on) causes a logic low at the electrical data output. Respectively, a
rising input edge causes a falling output edge and vice versa.
1000
85°C
25°C
-40°C
I
RSSI
/P
IN
- A/W
1
0.9
0.8
0.7
0.6
0.5
V
RSSI
- mV
100
10
1
-30
-20
-10
P
IN
- OPTICAL INPUT POWER - dBm
0
0.4
-50
0
50
T - TEMPERATURE - °C
100
Figure 1. Typical RSSI output voltage across R
RSSI
= 2 kΩ
Figure 2. Typical Responsivity vs. Temperature
Note:
To provide a suitable monitoring voltage, choose the value of RRSSI according to the particular optical power situation. For the characterization of
the responsivity, 2 kΩ was used. The lower the power, the higher the resistor value should be. Do not, however, override the max. limit of V
RSSI
.
3
Pin Description
Pin
1
2
3
4
5
6
7
8
Name
NC
/DO
VCC
NC
NC
RSSI
GND
NC
Function
NC
Data Out inverted (CMOS/TTL logic)
5V/3.3V Supply Voltage
NC
NC
Received Signal Strength Indicator Output
Ground
NC
Notes
1
2
1
1
4
3
2
1
5
6
7
8
PIN NO. 1 INDICATOR
1
BOTTOM VIEW
Notes
1. Pins 1, 4, 5 and 8 are connected together internally. The metal port option components (suffix MZ) have an internal electrical connection between
the metal port and the four grounding pins
2. The data output provides an inverted signal, thus an electrical low in case of light on and vice versa.
Recommended Circuitry
RXVCC
1
µH
C1
10
µF
GND
AFBR-24x8xZ
LL
L1
C2
100 nF
GND
V
CC
RSSI
DO
GND
3
6
2
7
R
RSSI
C3
100 nF
GND
GND GND
GND
V
RSSI
Monitoring
Rx
DO
2k
PHY
Recommended Transmitter Driver Circuitry for AFBR-24x8xZ receivers using HFBR-14x4xxZ
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