Description

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).

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.

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

(∑-Δ) analog-to-digital converter technology, chopper

stabilized amplifiers, and a fully differential 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 offset 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

IDD1

VDD1

VIN+

VIN–

GND1

IDD2

VDD2

VOUT+

VOUT–

GND2

+

–

+

–

SHIELD

HCPL-7840

Isolation Amplifier

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 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

 Advanced Sigma-Delta (∑-Δ) A/D converter technol-

ogy

 Fully differential 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