Energy Metering IC with Integrated Oscillator and Reverse Polarity Indication AD71056 FEATURES The AD71056 specifications surpass the accuracy requirements On-chip oscillator as clock source as quoted in the IEC62053-21 standard. High accuracy, supports 50 Hz/60 Hz IEC62053-21 The only analog circuitry used in the AD71056 is in the - Less than 0.1% error over a dynamic range of 500 to 1 ADCs and reference circuit. All other signal processing, such as Supplies average real power on frequency outputs (F1, F2) multiplication and filtering, is carried out in the digital domain. High frequency output (CF) calibrates and supplies This approach provides superior stability and accuracy over instantaneous real power time and in extreme environmental conditions. Logic output (REVP) indicates potential miswiring or negative power The AD71056 supplies average real power information on F1 Direct drive for electromechanical counters and 2-phase and F2, the low frequency outputs. These outputs either directly stepper motors (F1, F2) drive an electromechanical counter or interface with an MCU. Proprietary ADCs and DSP provide high accuracy over large The high frequency CF logic output, ideal for calibration variations in environmental conditions and time purposes, provides instantaneous real power information. On-chip power supply monitoring On-chip creep protection (no load threshold) The AD71056 includes a power supply monitoring circuit on On-chip reference 2.45 V (20 ppm/C typical) with external the V supply pin. The AD71056 remains inactive until the DD overdrive capability supply voltage on VDD reaches approximately 4 V. If the supply Single 5 V supply, low power (20 mW typical) falls below 4 V, the AD71056 also remains inactive and the F1, Low cost CMOS process F2, and CF outputs are in their nonactive modes. GENERAL DESCRIPTION Internal phase matching circuitry ensures that the voltage and current channels are phase matched, and the HPF in the current 1 The AD71056 is a high accuracy, electrical energy metering IC channel eliminates dc offsets. An internal no load threshold with a precise oscillator circuit that serves as a clock source to ensures that the AD71056 does not exhibit creep when no load the chip. The AD71056 eliminates the need for an external is present. crystal or resonator, thus reducing the overall cost of building a meter with this IC. The chip directly interfaces with the shunt The part is available in a 16-lead, narrow body SOIC package. resistor. FUNCTIONAL BLOCK DIAGRAM V AGND DGND DD 1 6 13 AD71056 POWER SUPPLY MONITOR SIGNAL PROCESSING BLOCK V2P 2 ...110101... + - ADC MULTIPLIER V2N 3 PHASE LPF CORRECTION ...11011001... 4 V1N - ADC HPF V1P 5 + DIGITAL-TO-FREQUENCY INTERNAL CONVERTER OSCILLATOR 4k 2.5V REFERENCE 7 11 8 10 9 12 14 16 15 RCLKIN REF SCF S0 S1 REVP CF F1 F2 IN/OUT Figure 1. 1 U.S. Patents 5,745,323 5,760,617 5,862,069 5,872,469 others pending. Rev. A Information furnished by Analog Devices is believed to be accurate and reliable. However, no responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. rights of third parties that may result from its use. Specifications subject to change without notice. No Tel: 781.329.4700 www.analog.com license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Fax: 781.461.3113 2006 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. 05636-001AD71056 TABLE OF CONTENTS Features .............................................................................................. 1 Power Factor Considerations.................................................... 10 General Description ......................................................................... 1 Nonsinusoidal Voltage and Current........................................ 10 Functional Block Diagram .............................................................. 1 Applications..................................................................................... 12 Revision History ............................................................................... 2 Analog Inputs ............................................................................. 12 Specifications..................................................................................... 3 Power Supply Monitor............................................................... 13 Timing Characteristics ................................................................ 4 Internal Oscillator (OSC).......................................................... 15 Absolute Maximum Ratings............................................................ 5 Transfer Function....................................................................... 15 ESD Caution.................................................................................. 5 Selecting a Frequency for an Energy Meter Application...... 16 Terminology ...................................................................................... 6 No Load Threshold .................................................................... 17 Pin Configuration and Function Descriptions............................. 7 Negative Power Information..................................................... 17 Typical Performance Characteristics ............................................. 8 Outline Dimensions ....................................................................... 18 Theory of Operation ...................................................................... 10 Ordering Guide .......................................................................... 18 REVISION HISTORY 8/06Revision A: Initial Version Rev. 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