For product information and a complete list of distributors, please go to our website: www.avagotech.com
Avago, Avago Technologies, and the A logo are trademarks of Avago Technologies in the United States and other countries.
Data subject to change. Copyright © 2005-2015 Avago Technologies. All rights reserved. Obsoletes AV01-0564EN
AV02-0641EN - July 21, 2015
Figure 24. Recommended PROFIBUS application circuit
Power Supplies and Bypassing
The recommended PROFIBUS application circuit is
shown in Figure 24. Since the HCPL-x710 are fully com-
patible with CMOS logic level signals, the optocoup-
ler is connected directly to the transceiver. Two bypass
capacitors (with values between 0.01 and 0.1 µF) are
required and should be located as close as possible to
the input and output power-supply pins of the HCPL-
x710. For each capacitor, the total lead length between
both ends of the capacitor and the power supply pins
should not exceed 20 mm. The bypass capac itors are
required because of the high-speed digital nature of
the signals inside the optocoupler.
Being very similar to multi-station RS485 systems, the
HCPL-061N optocoupler provides a transmit disable
function that is necessary to make the bus free after
each master/slave transmission cycle. Specically, the
HCPL-061N disables the transmitter of the line driver
by putting it into a high state mode. In addition, the
HCPL-061N switches the RX/TX driver IC into the listen
mode. The HCPL-061N oers HCMOS compatibility and
the high CMR performance (1 kV/µs at V
CM
= 1000 V)
essential in industrial communication interfaces.
1
2
3
8
6
4
7
5
V
DD2
V
O
GND
2
V
DD1
V
IN
GND
1
HCPL-x710
8
7
6
1
3
5
2
4
V
DD1
V
IN
GND
1
V
DD2
V
O
GND
2
HCPL-x710
5 V
0.01 µF
0.01 µF
0.01
µF
0.01
µF
R
A
SN75176B
V
CC
GND
DE
B
0.01
µF
ISO 5 V
1 M
0.01 µF
+
–
GALVANIC
ISOLATION
BOUNDARY
5 V ISO 5 V
RE
D
1
4
3
2
Rx
ISO 5 V
Tx
8
7
6
1
3
5
2
4
ANODE
V
CC
V
O
GND
5 V
0.01
µF
ISO 5 V
Tx ENABLE
CATHODE
V
E
680 Ω
HCPL-061N
1, 0 kΩ
5
7
6
8
RT
SHIELD
