HCPL-7840#500 Avago Technologies US Inc., HCPL-7840#500 Datasheet - Page 15

• Manufacturer Part Number: HCPL-7840#500
• Description: OPTOCOUPLER AMP 100KHZ 8-SMD
• Manufacturer: Avago Technologies US Inc.

Specifications of HCPL-7840#500

• Amplifier Type: Isolation
• Number Of Circuits: 1
• Output Type: Differential
• -3db Bandwidth: 100kHz
• Current - Input Bias: 500nA
• Voltage - Input Offset: 300µV
• Current - Supply: 10.9mA
• Current - Output / Channel: 15.5mA
• Voltage - Supply, Single/dual (±): 4.5 V ~ 5.5 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 8-SMD Gull Wing
• Operating Supply Voltage (typ): 5V
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant
• Slew Rate: -
• Gain Bandwidth Product: -
• Lead Free Status / RoHS Status: Not Compliant, Contains lead / RoHS non-compliant

• • •
As shown in Figure 18, 0.1 µF bypass capacitors (C1, C2)
should be located as close as possible to the pins of the
HCPL-7840. The bypass capacitors are required because
of the high-speed digital nature of the signals inside the
HCPL-7840. A 0.01 µF bypass capacitor (C2) is also rec-
ommended at the input due to the switched-capacitor
Figure 18: Recommended application circuit.
PC Board Layout
The design of the printed circuit board (PCB) should follow
good layout practices, such as keeping bypass capacitors
close to the supply pins, keeping output signals away
from input signals, the use of ground and power planes,
etc. In addition, the layout of the PCB can also affect the
isolation transient immunity (CMTI) of the HCPL-7840,
due primarily to stray capacitive coupling between the
input and the output circuits. To obtain optimal CMTI
performance, the layout of the PC board should minimize
any stray coupling by maintaining the maximum possible
distance between the input and output sides of the circuit
and ensuring that any ground or power plane on the PC
board does not pass directly below or extend much wider
than the body of the HCPL-7840.
15
MOTOR
R
+
SENSE
–
HV+
HV–
C1
0.1
µF
GATE DRIVE
• • •
FLOATING
POSITIVE
CIRCUIT
SUPPLY
IN
78L05
U1
OUT
R5
68
C2
0.1
µF
• • •
C3
0.01
µF
1
2
3
4
HCPL-7840
HCPL-7840 fig 18
U2
also forms part of the anti-aliasing filter, which is recom-
mended to prevent high-frequency noise from aliasing
down to lower frequencies and interfering with the input
signal. The input filter also performs an important reliabil-
ity function—it reduces transient spikes from ESD events
flowing through the current sensing resistor.
Figure 19. Example printed circuit board layout.
TO R
TO R
SENSE+
SENSE–
8
7
6
5
TO V
+5 V
C4
0.1 µF
DD1
150 pF
R5
2.00 K
2.00 K
C6
R1
R2
C3
R4
10.0 K
–
+
+15 V
-15 V
U3
150 pF
C2
10.0 K
C5
MC34081
R3
0.1 µF
C7
0.1 µF
C4
C8
TO V
V
V
OUT+
OUT–
V
DD2
OUT