Power Supplies and Bypassing
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.
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)
The recommended PROFIBUS
application circuit is shown in
Figure 24. Since the HCPL-x710
are 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
Being very similar to multi-station
RS485 systems, the HCPL-061N
optocoupler provides a transmit
disable function which is
essential in industrial
communication interfaces.
necessary to make the bus free
HCPL-x710. For each capacitor,
GALVANIC
ISOLATION
BOUNDARY
5 V
ISO 5 V
V
V
V
8
7
1
2
ISO 5 V
DD2
DD1
V
0.01 µF
IN
8
HCPL-x710
V
CC
0.01
µF
1
R
6
5
3
4
Rx
O
6
7
+
A
B
0.01
µF
RT
SHIELD
SN75176B
GND
GND
1
2
4
3
2
D
–
DE
RE
5 V
ISO 5 V
GND
5
V
V
DD2
1
2
8
7
DD1
0.01
µF
1 M
0.01 µF
V
Tx
IN
HCPL-x710
V
O
3
4
6
5
0.01 µF
GND
GND
2
1
ISO 5 V
V
1
2
8
7
CC
5 V
V
E
ANODE
680 Ω
0.01
µF
1, 0 kΩ
V
3
4
CATHODE
6
5
Tx ENABLE
O
GND
HCPL-061N
Figure 24. Recommended PROFIBUS application circuit.
16
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