ADE7751*

Features:

High Accuracy, Surpasses 50 Hz/60 Hz IEC 687/1036
Less than 0.1% Error over a Dynamic Range of 500 to 1
Supplies Average Real Power on the Frequency Outputs F1 and F2
High-Frequency Output CF Is Intended for Calibration and Supplies Instantaneous Real Power
Continuous Monitoring of the Phase and Neutral Current Allows Fault Detection in 2-Wire Distribution Systems
ADE7751 Uses the Larger of the Two Currents (Phase or Neutral) to Bill-Even During a Fault Condition
Two Logic Outputs (FAULT and REVP) Can Be Used to Indicate a Potential Miswiring or Fault Condition
Direct Drive for Electromechanical Counters and 2-Phase Stepper Motors (F1 and F2)
A PGA in the Current Channel Allows the Use of Small Values of Shunt and Burden Resistance
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)
Single 5 V Supply, Low Power (15 mW Typical)
Low-Cost CMOS Process


Pinout




Specifications

AV_DD to AGND  . . . . . . . . . . . . . . . . . . . . . . .  0.3 V to +7 V
DV_DD to DGND  . . . . . . . . . . . . . . . . . . . . . . . 0.3 V to +7 V
DV_DD  to AVDD  . . . . . . . . . . . . . . . . . . . . . 0.3 V to +0.3 V
Analog Input Voltage to AGND
V1A, V1B, V1N, V2P, and V2N  . . . . . . . . . .      6 V to +6 V
Reference Input Voltage to AGND  . 0.3 V to AVDD + 0.3 V
Digital Input Voltage to DGND  . . . .  0.3 V to DVDD + 0.3 V
Digital Output Voltage to DGND  . . 0.3 V to DVDD + 0.3 V
Operating Temperature Range
Industrial  . . . . . . . . . . . . . . . . . . . . . . . .  40°C to +85°C
Storage Temperature Range  . . . . . . . . .65°C to +150°C
Junction Temperature  . . . . . . . . . . . . . . . . . . . . . . .150°C
24-Lead Plastic DIP, Power Dissipation  . . . . . . . .450 mW
JA Thermal Impedance  . . . . . . . . . . . . . . . . . . .105°C/W
Lead Temperature, (Soldering 10 sec)  . . . . . . . . . .260°C
24-Lead SSOP, Power Dissipation  . . . . . . . . . . . .450 mW
_JA Thermal Impedance  . . . . . . . . . . . . . . . . . . .112°C/W
Lead Temperature, Soldering
Vapor Phase (60 sec)  . . . . . . . . . . . . . . . . . . . . . . 215°C
Infrared (15 sec)  . . . . . . . . . . . . . . . . . . . . . . . . . .220°C


Description

The ADE7751 is a high-accuracy, fault-tolerant electrical energy measurement IC that is intended for use with 2-wire distribution systems. The part specifications surpass the accuracy requirements as quoted in the IEC1036 standard.The only analog circuitry used in the ADE7751 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 ADE7751 incorporates a novel fault detection scheme that warns of fault conditions and allows the ADE7751 to continue accurate billing during a fault event. The ADE7751 does this by continuously monitoring both the phase and neutral (return) currents. A fault is indicated when these currents differ by more than 12.5%. Billing is continued using the larger of the two currents. The ADE7751 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. The ADE7751 includes a power supply monitoring circuit on the AVDD supply pin. The ADE7751 will remain in a reset condition until the supply voltage on AVDD reaches 4 V. If the supply falls below 4 V, the ADE7751 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 matched whether the HPF in Channel 1 is on or off. The ADE7751 also has anticreep protection. The ADE7751 is available in 24-lead DIP and SSOP packages.