Energy Metering IC with Integrated Oscillator and No-Load Indication ADE7769 FEATURES The ADE7769 specifications surpass the accuracy require- On-chip oscillator as clock source ments of the IEC62053-21 standard. The AN-679 Application High accuracy, supports 50 Hz/60 Hz IEC62053-21 Note can be used as a basis for a description of an IEC61036 Less than 0.1% error over a dynamic range of 500 to 1 (equivalent to IEC62053-21) low cost, watt-hour meter reference design. Supplies average real power on frequency outputs F1 and F2 High frequency output CF calibrates and supplies The only analog circuitry used in the ADE7769 is in the - instantaneous real power ADCs and reference circuit. All other signal processing, such as CF output remains logic high when ADE7769 is under multiplication and filtering, is carried out in the digital domain. no-load threshold This approach provides superior stability and accuracy over Logic output REVP indicates a potential miswiring or negative power time and extreme environmental conditions. Direct drive for electromechanical counters and 2-phase The ADE7769 supplies average real power information on the stepper motors (F1 and F2) low frequency outputs, F1 and F2. These outputs can be used to Proprietary ADCs and DSPs provide high accuracy over directly drive an electromechanical counter or interface with an large variations in environmental conditions and time MCU. The high frequency CF logic output, ideal for calibration On-chip power supply monitoring purposes, provides instantaneous real power information. On-chip creep protection (no-load threshold) On-chip reference 2.45 V (20 ppm/C typical) with external The ADE7769 includes a power supply monitoring circuit on overdrive capability the VDD supply pin. The ADE7769 remains inactive until the Single 5 V supply, low power (20 mW typical) supply voltage on VDD reaches approximately 4 V. If the supply Low cost CMOS process falls below 4 V, the ADE7769 also remains inactive and the F1, GENERAL DESCRIPTION F2, and CF outputs are in their nonactive modes. 1 The ADE7769 is a high accuracy electrical energy metering IC. Internal phase matching circuitry ensures that the voltage and It is a pin reduction version of the ADE7755 with an enhanced, current channels are phase matched, while the HPF in the precise oscillator circuit that serves as a clock source to the chip. current channel eliminates dc offsets. An internal no-load The ADE7769 eliminates the cost of an external crystal or threshold ensures that the ADE7769 does not exhibit creep resonator, thus reducing the overall cost of a meter built with when no load is present. During a no-load condition, the CF this IC. The chip directly interfaces with the shunt resistor. pin stays logic high. 1 The ADE7769 has a 16-lead, narrow body SOIC package. U.S. Patents 5,745,323 5,760,617 5,862,069 5,872,469 others pending. FUNCTIONAL BLOCK DIAGRAM V AGND DGND DD 1 6 13 ADE7769 POWER SUPPLY MONITOR SIGNAL PROCESSING BLOCK V2P 2 ...110101... + - ADC MULTIPLIER V2N 3 PHASE LPF CORRECTION 4 ...11011001... V1N - ADC HPF V1P 5 + DIGITAL-TO-FREQUENCY INTERNAL CONVERTER OSCILLATOR 2.5V 4k REFERENCE 7 11 8 10 9 12 14 16 15 REF RCLKIN SCF S0 S1 REVP CF F1 F2 IN/OUT Figure 1. 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 rights of third parties that may result from its use. One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A. Specifications subject to change without notice. No license is granted by implication Tel: 781.329.4700 www.analog.com or otherwise under any patent or patent rights of Analog Devices. Trademarks and registered trademarks are the property of their respective owners. Fax: 781.461.3113 2005 Analog Devices, Inc. All rights reserved. 05332-001ADE7769 TABLE OF CONTENTS Specifications..................................................................................... 3 Internal Oscillator (OSC).......................................................... 14 Timing Characteristics ................................................................ 4 Transfer Function....................................................................... 14 Absolute Maximum Ratings............................................................ 5 Selecting a Frequency for an Energy Meter Application ...... 15 ESD Caution.................................................................................. 5 No-Load Threshold.................................................................... 16 Terminology ...................................................................................... 6 Negative Power Information..................................................... 16 Pin Configuration and Function Descriptions............................. 7 Evaluation Board and Reference Design Board..................... 16 Typical Performance Characteristics ............................................. 8 Outline Dimensions....................................................................... 17 Functional Description .................................................................. 10 Ordering Guide .......................................................................... 17 Theory of Operation .................................................................. 10 Analog Inputs.............................................................................. 11 Power Supply Monitor ............................................................... 12 REVISION HISTORY 8/05Sp0 to Rev. A Rev. A Page 2 of 20