74OL6011W View Datasheet(PDF) - Fairchild Semiconductor
Part Name
Description
Manufacturer
74OL6011W Datasheet PDF : 15 Pages
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Application
Local area data communication systems can greately improve their noise immunity by including OPOTOLOGIC gates
in the design.
The Optologic input amplifier offers the feature of very high input impedance that permits their use as bridged line
receivers. The system show above illustrates an optically isolated transmitter and multidrop receiver system. The net-
work uses a 74OL6000 and buffer (Figure D) to isolate the transmitter and drive the 75Ω coax cable. This application
uses a 1000 ft. aerial suspension 75Ω CATV coax cable with data taps at 250 ft. intervals. The 74OL6001s function as
bridged receivers, and as many as 30 receivers could be placed along the line with minimal signal degradation. The
communication cable is terminated with a single 75Ω load at the far end of the line.
Signal quality "Eye Pattern" is shown in Figures A, B and C with a 10MBaud NRZ Psuedo-Random Sequence (PRS).
Traces 1-3 in Figure A describes the transmitter section. Traces 4-7 in Figure B show the output of the four Optologic
bridged terminations. Traces 8-11 in Figure C illustrate "Eye Pattern" as seen at the output of a 74LS04 logic gate. The
data quality is well preserved in that only a 30% Eye closure is seen at the receiver located 1000 ft. from the transmit-
ter.
The data communication system is completely optically isolated from all of the terminal equipments. Power for the
transmitter (VCCO) and receiver (VCCI) is taken from an isolated power supply and distributed through a drain or mes-
senger wire.
Figure A
Figure B
Figure C
HORIZONTAL = 20ns/DIV 42-11
VERTICAL = 2V/DIV
HORIZONTAL = 20ns/DIV 42-12, 02
VERTICAL = 2V/DIV
HORIZONTAL = 20ns/DIV 42-13/03
VERTICAL = 2V/DIV
0.1 µF
100 µF
1.1 KΩ
1.1 KΩ
2N4252
ALL DIODES
1N6263
1 KΩ
10 Ω
2N4252
PRSG
100 ns BIT
INTERVAL
1
2
3
74OL6000 BUFFER
250 FT.
1000 FT.
250 FT.
250 FT.
250 FT.
75 Ω
TERMINAION
2N2222
74 OL6001
74 OL6001
74 OL6001
74 OL6001
4
5
6
7
8 LS04
9 LS04
10 LS04
11 LS04
Figure D Buffer
©2000 Fairchild Semiconductor Corporation
74OL60XX Rev. 1.0.4
14
www.fairchildsemi.com
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