Optically Isolated Sigma-Delta Modulator


  • Superior Optical Isolation and Insulation
  • 20MHz internal clock
  • 1-bit, second-order sigma-delta modulator
  • 16 bits resolution no missing codes (12 bits ENOB)

The ACPL-C740 is a 1-bit, second-order sigma-delta (Ʃ-∆) modulator that converts an analog input signal into a high-speed data stream with galvanic isolation based on optical coupling technology. The ACPL-C740 operates from a 5 V power supply with a dynamic range of 80 dB with an appropriate digital filter. The differential inputs of ±200 mV (full scale ±320 mV) are ideal for direct connection to shunt resistors or other low-level signal sources in applications such as motor phase current measurement.

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  • 80 dB SNR
  • TBD μV/°C maximum offset drift
  • ±1% gain error
  • Internal reference voltage
  • ±200 mV linear range with single 5 V supply (±320 mV full scale)
  • 3V to 5.5V wide supply range for digital interface
  • –40°C to +110°C operating  temperature  range
  • SSO-8 package
  • 25 kV/μs common-mode transient immunity
  • Safety and regulatory approval:
    • IEC/EN/DIN EN 60747-5-5: 1414 Vpeak working insulation voltage
    • UL 1577: 5000 Vrms/1 min isolation voltage
    • CSA: Component Acceptance Notice #5
  • Motor phase and rail current sensing
  • Power Inverter current and voltage sensing
  • Industrial process control
  • Data acquisition systems
  • General purpose current and voltage sensing
  • Traditional current transducer replacements