Power Supplies and Bypassing
transceiver. Two bypass
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.
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
The recommended DeviceNet
application circuit is shown in
Figure 22. Since the HCPL-x710
are fully compatible with CMOS
logic level signals, the optocoupler
is connected directly to the CAN
GALVANIC
ISOLATION
BOUNDARY
ISO 5 V
5 V
LINEAR OR
SWITCHING
REGULATOR
+
V
V
V
DD2
1
2
8
7
DD1
IN
+
0.01
µF
TX0
HCPL-x710
V
CC
5 V+
TxD
Rs
V
O
0.01 µF
3
4
6
5
CANH
4 CAN+
3 SHIELD
2 CAN–
1 V–
82C250
GND
GND
GND
+
1
2
2
C4
0.01 µF
CANL
REF
GND
VREF
RXD
GND
GND
5
6
4
3
1
C1
0.01 µF
500 V
0.01
µF
D1
R1
1 M
RX0
V
O
30 V
HCPL-x710
V
0.01 µF
7
8
2
1
IN
V
V
DD1
DD2
ISO 5 V
5 V
Figure 22. Recommended DeviceNet application circuit.
Implementing PROFIBUS with the
HCPL-x710
PROFIBUS USER:
CONTROL STATION
(CENTRAL PROCESSING)
OR FIELD DEVICE
An acronym for Process Fieldbus,
PROFIBUS is essentially a
twisted-pair serial link very
USER INTERFACE
FDL/APP
PROCESSOR
similar to RS-485 capable of
achieving high-speed communi-
cation up to 12 MBd. As shown in
Figure 23, a PROFIBUS Controller
UART
PBC
(PBC) establishes the connection
of a field automation unit (control
or central processing station) or a
field device to the transmission
medium. The PBC consists of the
line transceiver, optical isolation,
frame character transmitter/
receiver (UART), and the FDL/
APP processor with the interface
to the PROFIBUS user.
OPTICAL ISOLATION
TRANSCEIVER
MEDIUM
Figure 23. PROFIBUS Controller (PBC).
15
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