74OL6000 Fairchild Optoelectronics Group, 74OL6000 Datasheet - Page 14

• Manufacturer Part Number: 74OL6000
• Description: OPTOCOUPLER TTL BUFFER 6-DIP
• Manufacturer: Fairchild Optoelectronics Group
• Series: OPTOLOGIC™ OPTOPLANAR®r

Specifications of 74OL6000

• Voltage - Isolation: 5300Vrms
• Number Of Channels: 1, Unidirectional
• Current - Output / Channel: 40mA
• Data Rate: 15MBd
• Propagation Delay High - Low @ If: 60ns
• Input Type: Logic
• Output Type: Push-Pull, Totem-Pole
• Mounting Type: Through Hole
• Package / Case: 6-DIP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 740L6000; 740L6000GI; 740L6000QT; 740L6000QT; 74OL6000GI; 74OL6000QT; 74OL6000QT

© 2003 Fairchild Semiconductor Corporation
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 network 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 transmitter.
The data communication system is completely optically isolated from all of the terminal equipments. Power for the transmitter
(V
HORIZONTAL = 20 ns/DIV
VERTICAL = 2 V/DIV
ALL DIODES
CCO
1N6263
) and receiver (V
1.1 K Ω
100 µ F
0.1 µ F
Figure D Buffer
Figure A
2N4252
1 K Ω
1.1 K Ω
CCI
) is taken from an isolated power supply and distributed through a drain or messenger wire.
42-11
2N4252
2N2222
10 Ω
HORIZONTAL = 20 ns/DIV
VERTICAL = 2 V/DIV
LSTTL TO
100 ns BIT
INTERVAL
PRSG
LOGIC-TO-LOGIC OPTOCOUPLERS
Page 14 of 15
Figure B
74
1
OL
6000
2
OPTOPLANAR
BUFFER
3
42-12, 02
250 FT.
TTL BUFFER
TTL INVERTER
CMOS BUFFER
CMOS INVERTER
4
8
74
LS04
OL
250 FT.
6001
1000 FT.
5
9
HORIZONTAL = 20 ns/DIV
VERTICAL = 2 V/DIV
74
LS04
OL
250 FT.
6001
®
10
6
HIGH-SPEED
74
LS04
OL
250 FT.
Figure C
6001
11
7
74
LS04
OL
74OL6000
74OL6001
74OL6010
74OL6011
6001
75
TERMINAION
Ω
10/1/03
42-13/03