Power Supplies and
Bypassing
The recommended PROFIBUS
application circuit is shown in
Figure 23. Since the HCPL-0710
is fully compatible with CMOS
logic level signals, the
optocoupler 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-
0710. 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
capacitors are required because
of the high-speed digital nature of
the signals inside the optocoupler.
sary to make the bus free after
each master/slave transmission
cycle. Specifically, 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 offers HCMOS
compatibility and the high CMR
performance (1 kV/µs at VCM =
1000 V) essential in industrial
communication interfaces.
Being very similar to multi-station
RS485 systems, the HCPL-061N
optocoupler provides a transmit
disable function which is neces-
GALVANIC
ISOLATION
BOUNDARY
ISO 5 V
5 V
V
V
V
DD1
8
7
1
2
5 V
8
DD2
V
0.01 µF
IN
HCPL-0710
V
CC
0.01
µF
1
R
6
5
3
4
Rx
O
6
+
–
A
B
0.01
µF
RT
SN75176B
GND
GND
1
2
4
2
3
7
D
RE
DE
ISO 5 V
5 V
GND
5
V
V
DD2
1
2
8
7
DD1
0.01
µF
1 M
0.01 µF
V
Tx
IN
HCPL-0710
V
O
3
4
6
5
0.01 µF
GND
GND
2
1
5 V
V
1
2
8
7
CC
ISO 5 V
V
E
ANODE
1 kΩ
0.01
µF
1, 5 kΩ
V
3
4
CATHODE
6
5
Tx ENABLE
O
GND
HCPL-061N
Figure 23. Recommended PROFIBUS Application Circuit.
AGILENT [ AGILENT TECHNOLOGIES, LTD. ]
