Isolation Amplifier
Technical Data
HCPL-7840
Features
Description
• 15 kV/µs Common-Mode
Rejection at VCM = 1000 V
• Compact, Auto-Insertable
Standard 8-pin DIP Package
• 0.00025 V/V/°C Gain Drift vs.
Temperature
• 0.3 mV Input Offset Voltage
• 100 kHz Bandwidth
• 0.004% Nonlinearity
• Worldwide Safety Approval:
UL 1577 (3750 Vrms/1 min.)
and CSA, IEC/EN/DIN EN
60747-5-2 (Option #060
only)
• Advanced Sigma-Delta (Σ−∆)
A/D Converter Technology
• Fully Differential Circuit
Topology
• 0.8 µm CMOS IC Technology
The HCPL-7840 isolation amplifier
family was designed for current
sensing in electronic motor drives.
In a typical implementation, motor
currents flow through an external
resistor and the resulting analog
voltage drop is sensed by the
HCPL-7840. A differential output
voltage is created on the other
side of the HCPL-7840 optical
isolation barrier. This differential
output voltage is proportional to
the motor current and can be converted to a single-ended signal by
using an op-amp as shown in the
recommended application circuit.
Since common-mode voltage
swings of several hundred volts in
tens of nanoseconds are common
in modern switching inverter
motor drives, the HCPL-7840
was designed to ignore very high
common-mode transient slew
rates (of at least 10 kV/µs).
Applications
• Motor Phase and Rail
Current Sensing
• Inverter Current Sensing
• Switched Mode Power
Supply Signal Isolation
• General Purpose Current
Sensing and Monitoring
• General Purpose Analog
Signal Isolation
The high CMR capability of the
HCPL-7840 isolation amplifier
provides the precision and
stability needed to accurately
monitor motor current in high
noise motor control environ-
ments, providing for smoother
control (less “torque ripple”) in
various types of motor control
applications.
Functional Diagram
IDD1
VDD1
VIN+
2
+
VIN–
3
–
GND1
4
IDD2
1
8
VDD2
+
7
VOUT+
–
6
VOUT–
5
GND2
SHIELD
The product can also be used for
general analog signal isolation
applications requiring high
accuracy, stability, and linearity
under similarly severe noise conditions. For general applications,
we recommend the HCPL-7840
(gain tolerance of ± 5%). The
HCPL-7840 utilizes sigma delta
(∑-∆ ) analog-to-digital converter
technology, chopper stabilized
amplifiers, and a fully differential
circuit topology fabricated using
CAUTION: It is advised that normal static precautions be taken in handling and assembly of this component to
prevent damage and/or degradation which may be induced by ESD.
3
Gull Wing Surface Mount Option 300
LAND PATTERN RECOMMENDATION
9.80 ± 0.25
(0.386 ± 0.010)
8
7
6
1.016 (0.040)
5
A 7840
6.350 ± 0.25
(0.250 ± 0.010)
YYWW
1
2
3
10.9 (0.430)
4
2.0 (0.080)
1.27 (0.050)
9.65 ± 0.25
(0.380 ± 0.010)
1.780
(0.070)
MAX.
1.19
(0.047)
MAX.
7.62 ± 0.25
(0.300 ± 0.010)
0.20 (0.008)
0.33 (0.013)
3.56 ± 0.13
(0.140 ± 0.005)
1.080 ± 0.320
(0.043 ± 0.013)
0.635 ± 0.25
(0.025 ± 0.010)
2.54
(0.100)
BSC
0.635 ± 0.130
(0.025 ± 0.005)
DIMENSIONS IN MILLIMETERS (INCHES).
TOLERANCES (UNLESS OTHERWISE SPECIFIED): xx.xx = 0.01
xx.xxx = 0.005
NOTE: FLOATING LEAD PROTRUSION IS 0.5 mm (20 mils) MAX.
12° NOM.
LEAD COPLANARITY
MAXIMUM: 0.102 (0.004)
