HFBR-24x6 Low-Cost 125 MHz
Receiver
preamplifier integrated circuit.
The HFBR-24x6 receives an
optical signal and converts it to
an analog voltage. The output is
a buffered emitter follower.
Because the signal amplitude
from the HFBR-24x6 receiver is
much larger than from a simple
PIN photodiode, it is less
receiver from noisy host
systems. Refer to AN 1038, 1065,
or AB 78 for details.
Description
The HFBR-24x6 fiber optic
receiver is designed to operate
with the Agilent HFBR-14xx
fiber optic transmitters and 50/
125 µm, 62.5/125 µm, 100/140
Housed Product
6
Vcc
2
ANALOG SIGNAL
3 & 7
VEE
µm and 200 µm HCS® fiber optic susceptible to EMI, especially at
4
3
2
1
5
6
7
8
cable. Consistent coupling into
the receiver is assured by the
high signaling rates. For very
noisy environments, the
lensed optical system (Figure 1). conductive or metal port option
BOTTOM VIEW
PIN 1 INDICATOR
Response does not vary with
fiber size for core diameters of
100 mm or less.
is recommended. A receiver
dynamic range of 23 dB over
temperature is achievable
(assuming 10-9 BER).
PIN
11
2
FUNCTION
NC
SIGNAL
VEE
NC
NC
VCC
VEE
NC
32
41
51
6
72
81
The receiver output is an analog
signal which allows follow-on
circuitry to be optimized for a
variety of distance/data rate
NOTES:
The frequency response is
typically dc to 125 MHz.
Although the HFBR-24x6 is an
1. PINS 1, 4, 5 AND 8 ARE ISOLATED FROM THE INTERNAL
CIRCUITRY, BUT ARE ELECTRICALLY CONNECTED TO EACH
OTHER.
2. PINS 3 AND 7 ARE ELECTRICALLY CONNECTED TO HEADER
requirements. Low-cost external analog receiver, it is compatible
components can be used to
convert the analog output to
with digital systems. Please refer
to Application Bulletin 78 for
Unhoused Product
logic compatible signal levels for simple and inexpensive circuits
various data formats and data
rates up to 175 MBd. This
distance/data rate trade-off
results in increased optical
power budget at lower data
rates which can be used for
additional distance or splices.
that operate at 155 MBd or
higher.
PIN FUNCTION
1
2
3
4
SIGNAL
VEE
VCC
1
4
2
3
VEE
The recommended ac coupled
receiver circuit is shown in
Figure 14. It is essential that a
10 ohm resistor be connected
between pin 6 and the power
supply, and a 0.1 mF ceramic
bypass capacitor be connected
between the power supply and
ground. In addition, pin 6
BOTTOM VIEW
The HFBR-24x6 receiver
contains a PIN photodiode and
low noise transimpedance
should be filtered to protect the
6
POSITIVE
SUPPLY
BIAS & FILTER
CIRCUITS
V
CC
300 pF
2
ANALOG
SIGNAL
V
OUT
5.0
mA
3, 7
NEGATIVE
SUPPLY
V
EE
Figure 13. Simplified Schematic Diagram.
CAUTION: The small junction sizes inherent to the design of these components increase the components’ susceptibility to damage
from electrostatic discharge (ESD). It is advised that normal static precautions be taken in handling and assembly of these
components to prevent damage and/or degradation which may be induced by ESD.
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