HCPL-0720-500E Datasheet, PDF (18/18 Pages) AVAGO TECHNOLOGIES LIMITED – 40 ns Propagation Delay, CMOS Optocoupler

Power Supplies and Bypassing
The recommended PROFIBUS application circuit is
shown in Figure 23. Since the HCPL-772X/072X are fully
compatible 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-
772X/072X. For each capacitor, the total lead length be-
tween 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.
Being very similar to multi-station RS485 systems, the
HCPL-061N optocoupler provides a transmit disable
function which is necessary 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 V_CM = 1000 V) es-
sential in industrial communication interfaces.
GALVANIC
ISOLATION
BOUNDARY
5V
ISO 5 V
8 VDD2
VDD1 1
ISO 5 V
0.01 µF
7
VIN ₂
Rx
HCPL-772x
6 VO ^HCPL-072x
3
0.01
µF
5 GND2
GND1 4
8
0.01
1R
VCC
A6
+
µF
SN75176B
RT
SHIELD
4D
B7
–
5V
ISO 5 V
1 VDD1
VDD2 8
Tx
2 VIN
0.01
7
µF
3 _DE
2 _RE
GND
5
0.01 µF
1M
HCPL-772x
0.01 µF
3
HCPL-072x VO ₆
4 GND1
GND2 5
Tx ENABLE
5V
1, 0 kΩ
ISO 5 V
1
VCC 8
2 ANODE
VE ₇
HCPL-061N
0.01
µF
3 CATHODE
VO 6
4
GND 5
680 Ω
Figure 23. Recommended PROFIBUS application circuit
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Data subject to change. Copyright © 2005-2013 Avago Technologies. All rights reserved. Obsoletes AV01-0565EN
AV02-0876EN - April 5, 2013