Description
The HCPL-7840 isolation ampli er family was designed
for current sensing in electronic motor drives. In a typical
implementation, motor currents ow through an external
resistor and the resulting analog voltage drop is sensed by
the HCPL-7840. A di erential output voltage is created on
the other side of the HCPL-7840 optical isolation barrier.
This di erential 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).
The high CMR capability of the HCPL-7840 isolation
ampli er 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.
The product can also be used for general analog signal
isolation applications requiring high accuracy, stability,
and linearity under similarly severe noise con-ditions. 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 ampli ers, and a fully di erential circuit topol-
ogy fabricated using Avago’s 0.8 µm CMOS IC process.
Together, these features deliver unequaled isolation-
mode noise rejection, as well as excellent o set and gain
accuracy and stability over time and temperature. This
performance is delivered in a compact, auto-insertable,
industry standard 8-pin DIP package that meets world-
wide regulatory safety standards. (A gull-wing surface
mount option #300 is also available).
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.
1
2
3
4
8
7
6
5
I
DD1
V
DD1
V
IN+
V
IN–
GND1
I
DD2
V
DD2
V
OUT+
V
OUT–
GND2
+
–
+
–
SHIELD
HCPL-7840
Isolation Ampli er
Data Sheet
Features
15 kV/µs common-mode rejection at V
CM
= 1000 V
Compact, auto-insertable standard 8-pin DIP package
0.00025 V/V/°C gain drift vs. temperature
0.3 mV input o set 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
Advanced Sigma-Delta (∑-∆) A/D converter technol-
ogy
Fully di erential circuit topology
0.8 µm CMOS IC technology
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
Functional Diagram
A 0.1 µF bypass capacitor must be connected
between pins 1 and 4 and between pins 5 and 8.
Lead (Pb) Free
RoHS 6 fully
compliant
RoHS 6 fully compliant options available;
-xxxE denotes a lead-free product
