HFBR-1402C HP [Agilent(Hewlett-Packard)], HFBR-1402C Datasheet - Page 11

• Manufacturer Part Number: HFBR-1402C
• Description: Components is Designed to Provide cost effective, High performance fiber optic communication links
• Manufacturer: HP [Agilent(Hewlett-Packard)]

5 MBd Logic Link Design
If resistor R1 in Figure 2 is 70.4
W, a forward current I
is applied to the HFBR-14x4
LED transmitter. With I
mA the HFBR-14x4/24x2 logic
link is guaranteed to work with
62.5/125 µm fiber optic cable
over the entire range of 0 to
1750 meters at a data rate of dc
to 5 MBd, with arbitrary data
format and pulse width
distortion typically less than
25%. By setting R
transmitter can be driven with
I
economize on power or achieve
lower pulse distortion.
Figure 2. Typical Circuit Configuration.
11
+5 V
F
DATA IN
NOTE:
IT IS ESSENTIAL THAT A BYPASS CAPACITOR (0.01 µF TO 0.1 µF
CERAMIC) BE CONNECTED FROM PIN 2 TO PIN 7 OF THE RECEIVER.
TOTAL LEAD LENGTH BETWEEN BOTH ENDS OF THE CAPACITOR
AND THE PINS SHOULD NOT EXCEED 20 MM.
= 30 mA, if it is desired to
1 KΩ
SELECT R
½ 75451
R
1
1
TO SET I
I
F
1
F
= 115 W, the
2
6
7
3
TRANSMITTER
F
HFBR-14xx
T
of 48 mA
F
= 48
The following example will
illustrate the technique for
selecting the appropriate value
of I
Maximum distance required =
400 meters. From Figure 3 the
drive current should be 15 mA.
From the transmitter data V
1.5 V (max.) at I
shown in Figure 9.
R
R
1
1
=
=
F
233
V
and R
CC
I
−
F
Ω
V
1
F
.
=
TRANSMISSION
5V
DISTANCE =
F
−
= 15 mA as
1.5V
15
mA
F
=
The curves in Figures 3, 4, and 5
are constructed assuming no
inline splice or any additional
system loss. Should the link
consists of any in-line splices,
these curves can still be used to
calculate link limits provided
they are shifted by the
additional system loss expressed
in dB. For example, Figure 3
indicates that with 48 mA of
transmitter drive current, a 1.75
km link distance is achievable
with 62.5/125 µm fiber which
has a maximum attenuation of 4
dB/km. With 2 dB of additional
system loss, a 1.25 km link
distance is still achievable.
HFBR-24x2
RECEIVER
R
7 & 3
2
6
TTL DATA OUT
R
L
0.1 µF
V
CC