ADI AD7755AARS

The AD7755 is a high accuracy electrical energy measurement IC. The part specifications surpass the accuracy requirements as quoted in the IEC1036 standard. The only analog circuitry used in the AD7755 is in the ADCs and reference circuit. All other signal processing (e.g., multiplication and filtering) is carried out in the digital domain. This approach provides superior stability and accuracy over extremes in environmental conditions and over time. The AD7755 supplies average real power information on the low frequency outputs F1 and F2. These logic outputs may be used to directly drive an electromechanical counter or interface to an MCU. The CF logic output gives instantaneous real power information. This output is intended to be used for calibration purposes, or interfacing to an MCU. The AD7755 includes a power supply monitoring circuit on the AVDD supply pin. The AD7755 will remain in a reset condition until the supply voltage on AVDD reaches 4 V. If the supply falls below 4 V, the AD7755 will also be reset and no pulses will be issued on F1, F2 and CF. Internal phase matching circuitry ensures that the voltage and current channels are phase matched whether the HPF in Channel 1 is on or off. An internal no-load threshold ensures that the AD7755 does not exhibit any creep when there is no load. The AD7755 is available in 24-lead DIP and SSOP packages.

• High Accuracy, Supports 50 Hz/60 Hz IEC 687/1036
• Less than 0.1% Error Over a Dynamic Range of 500 to 1
• The AD7755 Supplies Average Real Power on the Frequency Outputs F1 and F2
• The High Frequency Output CF Is Intended for Calibration and Supplies Instantaneous Real Power
• The Logic Output REVP Can Be Used to Indicate a Potential Miswiring or Negative Power
• Direct Drive for Electromechanical Counters and Two Phase Stepp Motors (F1 and F2)
• A PGA on the Current Input Allows the Use of Small Value Shunt Resistors
• Proprietary ADCs and DSP Provide High Accuracy over Large Variations in Environmental Conditions and Time
• On-Chip Power Supply Monitoring
• On-Chip Creep Protection (No Load Threshold)
• On-Chip Reference 2.5 V ± 8% (30 ppm/°C Typical) with External Overdrive Capability
• Single 5 V Supply, Low Power (15 mW Typical)
• Low Cost CMOS Process