Avago Technologies ACPL-224-500E - Manual (Page 37)

AV02-4387EN 34 Avago Technologies
Description
Profibus (Process Fieldbus) is essen-
tially a twisted wire pair serial link
very similar to RS-485 or 422. Profi-
bus speed standard is either lower
speed (1.5 MBd) or higher speed
(12 MBd). In this isolated multipoint
transmission application circuit, two
different optoisolators are utilized
(HCPL-0721 and HCPL-061N).
Performance of Circuit
• Typical data rate (NRZ): Up to 12
Mbit/s
• Multipoint bus transmission line
application
• Compatible with 5 V CMOS and
TTL logic gates
• Maximum propagation delay of
optoisolator: 0.04 µsec
• Minimum common mode tran-
sient immunity: 10 kV/ µsec at V
CM
= 1000 V
Isolated PROFIBUS/RS-485 12 MB/s Communication Application
Benefits
• Low input drive current maximiz-
es LED lifetime/reliability
• Speed optimized for Profibus and
RS-485
• Performance guaranteed over
temperature (-40 to 85°C)
Data Communications Applications
8
5 V ISO 5 V
7
1
2
3
4
6
5
SHIELD
HCPL-0721
0.01 µF
0.01 µF
R X
1
5 V ISO 5 V
2
8
7
6
5
3
4
SHIELD
HCPL-0721
0.01 µF
0.01 µF
T X
1
2
8
7
6
5
3
4
SHIELD
HCPL-061N
1 k Ω
T X
ENABLE
5 V
ISO 5 V
0.01 µF
680
Ω
1M
ISO 5 V
REG
0.01 µF
+
6
75ALS176D
8
–
R T
7
A
R
D
DE
RE
B
0.01
µF
GND
V CC
1
4
3
2
5
ISO 5 V