HFBR-24X6 Low-Cost 125 MHz
Receiver
Description
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
receiver from noisy host systems.
Refer to AN 1038, 1065, or AB 78
for details.
The HFBR-24X6 fiber optic
receiver is designed to operate
with the Avago HFBR-14XX fiber
optic transmitters and 50/125
µm, 62.5/125 µm, 100/140 µm
amplitude from the HFBR-24X6
receiver is much larger than from a
simple PIN photodiode, it is less
susceptible to EMI, especially at
high signaling rates. For very noisy
environments, the conductive or
metal port option is recommended.
A receiver dynamic range of 23 dB
over temperature is achievable
Housed Product
6
V
CC
ANALOG
SIGNAL
2
®
and 200 µm HCS fiber optic
3 & 7
cable. Consistent coupling into
the receiver is assured by the
lensed optical system (Figure 1).
Response does not vary with fiber
size for core diameters of 100 µm
or less.
V
EE
4
3
2
1
5
6
7
8
-9
(assuming 10 BER).
BOTTOM VIEW
PIN NO. 1
INDICATOR
The frequency response is typically
dc to 125 MHz. Although the
HFBR-24X6 is an analog receiver,
it is compatible with digital
The receiver output is an analog
signal which allows follow-on
circuitry to be optimized for a
variety of distance/data rate
requirements. Low-cost external
components can be used to convert
the analog output to logic
PIN FUNCTION
1†
N.C.
2
SIGNAL
3*
4†
5†
6
7*
8†
V
N.C.
N.C.
V
V
N.C.
EE
systems. Please refer to
CC
EE
Application Bulletin 78 for simple
and inexpensive circuits that
operate at 155 MBd or higher.
compatible signal levels for various
data formats and data rates up to
175 MBd. This distance/data rate
tradeoff results in increased optical
power budget at lower data rates
which can be used for additional
distance or splices.
* PINS 3 AND 7 ARE ELECTRICALLY
CONNECTED TO THE HEADER.
The recommended ac coupled
receiver circuit is shown in Figure
12. It is essential that a 10 ohm
resistor be connected between pin
6 and the power supply, and a 0.1
µF ceramic bypass capacitor be
connected between the power
supply and ground. In addition, pin
6 should be filtered to protect the
† PINS 1, 4, 5, AND 8 ARE ISOLATED FROM
THE INTERNAL CIRCUITRY, BUT ARE
ELECTRICALLY CONNECTED TO EACH OTHER.
Unhoused Product
PIN FUNCTION
The HFBR-24X6 receiver contains
a PIN photodiode and low noise
transimpedance pre-amplifier
1
2*
3
SIGNAL
V
EE
V
CC
V
EE
4*
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 11. Simplified schematic diagram.
CAUTION: The sma ll junction sizes inher ent to the design of these components incr ea se the components’
susceptibility to da ma ge fr om electr osta tic discha r ge (ESD). It is a dvised tha t nor ma l sta tic pr eca utions be
ta ken in ha ndling a nd a ssembly of these components to pr event da ma ge a nd/ or degr a da tion which ma y be
induced by ESD.
21