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Analog Devices Inc. ADE7932/ADE7933 Isolated, Sigma Delta ADCs

Analog Devices Inc. ADE7932/ADE7933 Isolated Sigma-Delta Analog-to-Digital Converters (Σ-Δ ADCs) for polyphase energy metering applications that use shunt current sensors. ADE7932 features two 24-bit ADCs, while the ADE7933 features three 24-bit ADCs. One channel is dedicated to measuring the voltage across the shunt when a shunt is used for current sensing. This channel has a signal-to-noise ratio (SNR) of 67dB over a 3.3kHz signal bandwidth. Up to two additional channels are dedicated to measuring voltages, which are usually sensed using resistor dividers. These channels provide an SNR of 75dB over a 3.3kHz signal bandwidth. One voltage channel can be used to measure the temperature of the die via an internal sensor. 

Based on proprietary iCoupler® technology, this DC-to-DC converter provides the regulated power required by the first stage of the ADCs at a 3.3V input supply. The ADE7933/ADE7932 eliminate the need for an external DC-to-DC isolation block. The iCoupler chip scale transformer technology is used to isolate the logic signals between the first and second stages of the ADC. The result is a small form factor, total isolation solution.

Features

  • Enables shunt current sensors in polyphase energy meters
  • Immune to magnetic tampering
  • Highly accurate; supports EN 50470-1, EN 50470-3, IEC 62053-21, IEC 62053-22, IEC 62053-23, ANSI C12.20, and IEEE 1459 standards
  • Compatible with 3-phase, 3- or 4-wire (delta or wye) meters and other 3-phase services
  • Computes active, reactive, and apparent energy on each phase and on the overall system
  • Less than 0.2% error in active and reactive energy over a dynamic range of 2000 to 1 at TA = 25°C
  • Less than 0.1% error in voltage rms over a dynamic range of 500 to 1 at TA = 25°C
  • Power quality measurements including THD
  • Single 3.3V supply

Applications

  • Shunt-based polyphase meters
  • Power quality monitoring
  • Solar inverters
  • Process monitoring
  • Protective devices
  • Isolated sensor interfaces
Published: 2014-04-14 | Updated: 2022-03-11