The HCPL-7840 isolation amplifier family was designed for current sensing in electronic motor drive applications. 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. 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/ms).
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 environments, 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 conditions. For general applications, we recommend the HCPL-7840 (gain tolerance of /- 5%). The HCPL-7840 utilizes sigma delta (S-D) analog-to-digital converter technology, chopper stabilized amplifiers, and a fully differential circuit topology fabricated using Broadcom'ss 0.8 mm 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 worldwide regulatory safety standards. (A gull-wing surface mount option #300 is also available).
- Motor Phase and Rail Current Sensing
- Inverter Current Sensing
- DC Bus Voltage Sensing
- Switched Mode Power Supply Signal Isolation
- General Purpose Current Sensing and Monitoring
- General Purpose Analog Signal Isolation
- Traditional Hall Effect Sensor Replacement
- 15 kV/ms Common-Mode Rejection at VCM = 1000 V
- Compact, Auto-Insertable Standard 8-pin DIP Package
- 0.00025 V/V/ degrees 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 (pending), IEC/EN/DIN EN 60747-5-2 (option 060 only)
- Advanced Sigma-Delta (S-D) A/D Converter Technology
- Fully Differential Circuit Topology
- 0.8 mm CMOS IC Technology
- Options available are:
No Option = Standard DIP package, 50 per tube 060 = IEC/EN/DIN EN 60747-5-2 Option 300 = Surface Mount Option 500 = Tape/Reel Packaging Option, 1 k min. per reel XXXE = Lead Free Option