Precision Miniature Isolation Amplifiers

By Broadcom Limited 257

Precision Miniature Isolation Amplifiers

Broadcom Limited ACPL-C79B/C79A/C790 isolation amplifiers were designed for current and voltage sensing in electronic power converters in applications including motor drives and renewable energy systems. In a typical motor drive implementation, current flows through an external resistor and the resulting analog voltage drop is sensed by the isolation amplifier. A differential output voltage that is proportional to the current is created on the other side of the optical isolation barrier.

For general applications, the ACPL-C79A (±1% gain tolerance) and the ACPL-C790 (±3% gain tolerance) are recommended. For high precision applications, the ACPL-C79B (±0.5% gain tolerance) can be used. The product operates from a single 5 V supply and provides excellent linearity and dynamic performance of 60 dB SNR. With 200 kHz bandwidth, 1.6 µs fast response time, the product captures transients in short circuit and overload conditions. The high common-mode transient immunity (15 kV/µs) of the ACPL-C79B/C79A/C790 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.

  • ±0.5% high gain accuracy (ACPL-C79B)
  • -50 ppm/°C low gain drift
  • 0.6 mV input offset voltage
  • 60 dB SNR
  • 200 kHz wide bandwidth
  • 3 V to 5.5 V wide supply range for output side
  • -40°C to +105°C operating temperature range
  • Fully differential isolation amplifier
  • Advanced sigma-delta (Σ–Δ) A/D converter technology
  • 15 kV/μs common-mode transient immunity
  • Compact, auto-insertable stretched SO-8 package
  • Safety and regulatory approvals:
    • IEC/EN/DIN EN 60747-5-5: 1230 VPEAK working insulation voltage
    • UL 1577: 5000 VRMS/1min double protection rating
    • CSA: component acceptance notice #5
  • Current/voltage sensing in AC and servo motor drives
  • Solar inverters, wind turbine inverters
  • Industrial process control
  • Data acquisition systems
  • Switching power supply signal isolation
  • General purpose analog signal isolation
  • Traditional current transducer replacements