Datasheet

16
Power Supplies and Bypassing
The recommended DeviceNet application circuit is
shown in Figure 22. Since the HCPL-x710 are fully com-
patible with CMOS logic level signals, the optocoupler is
connected directly to the CAN transceiver. Two bypass
capacitors (with values between 0.01 and 0.1 µF) are
required and should be located as close as possible to
Figure 22. Recommended DeviceNet application circuit.
Implementing PROFIBUS with the HCPL-x710
An acronym for Process Fieldbus, PROFIBUS is essen-
tially a twisted-pair serial link very similar to RS-485
capable of achieving high-speed communication up to
12 MBd. As shown in Figure 23, a PROFIBUS Controller
(PBC) establishes the connection of a eld automation
unit (control or central processing station) or a eld
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.
Figure 23. PROFIBUS Controller (PBC).
PROFIBUS USER:
CONTROL STATION
(CENTRAL PROCESSING)
OR FIELD DEVICE
USER INTERFACE
FDL/APP
PROCESSOR
TRANSCEIVER
OPTICAL ISOLATION
UART
PBC
MEDIUM
HCPL-0710 fig 22
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 capacitors are
required because of the high-speed digital nature of the
signals inside the optocoupler.
HCPL-0710 fig 21
8
7
6
1
3
5
2
4
V
DD1
V
IN
GND
1
V
DD2
V
O
GND
2
HCPL-0710
4
3
2
5
7
1
6
8
GND
2
V
O
V
DD2
GND
1
V
IN
V
DD1
HCPL-0710
GND
ISO 5 V
ISO 5 V
0.01 µF
RX0
0.01 µF
TX0
0.01
µF
0.01
µF
TxD
CANH
REF
RXD
82C250
V
CC
GND
Rs
CANL
C4
0.01 µF
+
VREF
LINEAR OR
SWITCHING
REGULATOR
5 V
5 V
+ +
R1
1 M
C1
0.01 µF
500 V
D1
30 V
5 V+
4 CAN+
3 SHIELD
2 CAN–
1 V–
GALVANIC
ISOLATION
BOUNDARY