ADE7768

The ADE77681 is a high accuracy, electrical energy metering IC. It is a pin reduction version of the ADE7755, enhanced with a precise oscillator circuit that serves as a clock source to the chip. The ADE7768 eliminates the cost of an external crystal or resonator, thus reducing the overall cost of a meter built with this IC. The chip directly interfaces with the shunt resistor.

The ADE7768 specifications surpass the accuracy require-ments of the IEC62053-21 standard. The AN-679 Application Note can be used as a basis for a description of an IEC61036 (equivalent to IEC62053-21) low cost, watt-hour meter reference design.

The only analog circuitry used in the ADE7768 is in the - ADCs and reference circuit. All other signal processing, such as multiplication and filtering, is carried out in the digital domain. This approach provides superior stability and accuracy over time and extreme environmental conditions.

The ADE7768 supplies positive-only average real power information on the low frequency outputs, F1 and F2. These outputs can be used to directly drive an electromechanical counter or interface with an MCU. The high frequency CF logic output, ideal for calibration purposes, provides instantaneous positive-only, real power information.

The ADE7768 includes a power supply monitoring circuit on the V_DD supply pin. The ADE7768 remains inactive until the supply voltage on V_DD reaches approximately 4 V. If the supply falls below 4 V, the ADE7768 also remains inactive and the F1, F2, and CF outputs are in their nonactive modes.

Internal phase matching circuitry ensures that the voltage and current channels are phase matched, while the HPF in the current channel eliminates dc offsets. An internal no-load threshold ensures that the ADE7768 does not exhibit creep when no load is present. When REVP is logic high, the ADE7768 does not generate any pulse on F1, F2, and CF.

The ADE7768 comes in a 16-lead, narrow body SOIC package.