DESCRIPTION The ADE7761 is a high accuracy, fault tolerant, electrical energy measurement IC intended for use with 2-wire distribution systems. The part specifications surpass the accuracy require-ments as quoted in the IEC61036 standard. The only analog circuitry used on the ADE7761 is in the ADCs and reference circuit. All other signal processing (such as multi-plication 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 ADE7761 incorporates a fault detection scheme similar to the ADE7751 by continuously monitoring both the phase and neutral currents. A fault is indicated when these currents differ by more than 6.25%. (continued on Page 3) FUNCTIONAL BLOCK DIAGRAM MISCALADC65V2PV2NADCADC437V1BADC2V1AAGNDFAULTVDDV1N2.5VREFERENCEINTERNALOSCILLATORMISSING NEUTRALGAIN ADJUSTMISSING NEUTRALDETECTION91417101112B>AA<>BA>BZERO CROSSINGDETECTIONADE7761SIGNAL PROCESSINGBLOCK151 FEATURES High accuracy active energy measurement IC, supports IEC 687/61036 Less than 0.1% error over a dynamic range of 500 to 1 Supplies active power on the frequency outputs F1 and F2 supplies instantaneous active power Continuous monitoring of the phase and neutral current allows fault detection in 2-wire distribution systems Current channels input level best suited for current transformer sensors Uses the larger of the two currents (phase or neutral) to bill even during a fault condition Continuous monitoring of the voltage and current inputs allows missing neutral detection Uses one current input (phase or neutral) to bill when missing neutral is detected Two logic outputs (FAULT and REVP) can be used to indicate a potential miswiring, fault, or missing neutral condition Direct drive for electromechanical counters and 2-phase stepper motors (F1 and F2) Proprietary ADCs and DSP provide high accuracy over large variations in environmental conditions and time Reference 2.5 V 8% (dri Specifications subject to change w