ACPL-C797

Optically Isolated Sigma-Delta Modulator

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The ACPL-C797 is a 1-bit, second-order sigma-delta modulator that converts an analog input signal into a high-speed data stream through integration of galvanic isolation based on optical coupling technology. The ACPL-C797 uses a 5 V power supply with dynamic range of 80 dB and 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.

The analog input is continuously measured by  the sigma-delta modulator  by over-sampling using an on-board clock. The signal information is contained in the modulator data, as a density of ones with data rate of 10 MHz. Data is then encoded and transmitted across the isolation boundary where it is recovered and decoded into high-speed data stream of digital ones and zeros. The original signal information can be reconstructed with a digital filter. The serial interface for data and clock has a wide supply range of 3 V to 5.5 V.

Combined with superior optical coupling technology, the modulator delivers high noise margins and excellent immunity against isolation-mode transients. With 0.5 mm minimum distance through insulation (DTI), the ACPL C797 provides reliable reinforced insulation and high working insulation voltage, which is suitable for fail-safe designs. This isolation performance is superior to alternatives including devices based on capacitive- or magnetic-coupling with DTI in micro-meter range. Offered in a   SO-16 package, the isolated ADC delivers the reliability, small size, superior isolation and over-temperature performance motor drive designers need to accurately measure current. This design alternative delivers a lower price when compared to traditional current transducers.

An external clock version modulator ACPL-796J (SO-16 package) is also available.

Features

  • 10 MHz internal clock
  • 1-bit, second-order sigma-delta modulator
  • 16 bits resolution no missing codes (12 bits ENOB)
  • TBD dB minimum SNR
  • 3.5 µV/°C maximum offset drift
  • ±1% maximum gain error
  • Internal reference voltage
  • ±200 mV linear range with single 5 V supply (±320 mV full scale)
  • 3 V to 5.5 V wide supply range for digital interface
  • –40°C to +105°C operating temperature range
  • Stretched SO-8 package
  • 25 kV/µs common-mode transient immunity
  •  Safety and regulatory Approval (pending): 
    • UL 1577 (5000 Vrms/1 min.)
    • CSA
    • IEC/EN/DIN EN 60747-5-5
       
  • Options available are :
    • 000E: Lead Free Option
    • 060E: IEC/EN/DIN EN 60747-5-5 Option
    • 500E: Tape and Reel Packaging Option

Applications

  • 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

Lifecycle Status

Active

Certifications

  • RoHS6
    Fully Compliant

Lifecycle Status

Active

Substance Compliance

  • RoHS6
    Fully Compliant
Specification Value
Lifecycle Active
Distrib. Inventory Yes
Samples Available Yes
RoHS6 Compliant Y
Max Qty of Samples 20
Product Type Isolated Modulator
Package Stretched SO8
Gain Error at 25 Deg C (%) Max ±1
VDD2 (V) 3 - 5.5
CMR (min.) (V/µs) 25000.0
Vcm (V) 1000.0
UL Insulation Rating Viso (VRMS) 5000.0
IEC Maximum Working Insulation Voltage Viorm (VPEAK) 1414.0
IEC Highest Allowable Overvoltage Viotm (VPEAK) 8000

Documentation

Application Note (1) i
Data Sheet (1) i
Product Change Notice (PCN) (2) i
White Papers (1) i