Datasheet AD71056 (Analog Devices)

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 Σ-Δ
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 instantaneous real power
This approach provides superior stability and accuracy over
Logic output (REVP) indicates potential miswiring or
time and in extreme environmental conditions.
negative power
The AD71056 supplies average real power information on F1
Direct drive for electromechanical counters and 2-phase stepper motors (F1, F2)
and F2, the low frequency outputs. These outputs either directly
Proprietary ADCs and DSP provide high accuracy over large
drive an electromechanical counter or interface with an MCU.
variations in environmental conditions and time
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)
The AD71056 includes a power supply monitoring circuit on
On-chip reference 2.45 V (20 ppm/°C typical) with external
the V
overdrive capability
DD supply pin. The AD71056 remains inactive until the supply voltage on V
Single 5 V supply, low power (20 mW typical)
DD reaches approximately 4 V. If the supply 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 The AD710561 is a high accuracy, electrical energy metering IC current channels are phase matched, and the HPF in the current 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 VDD AGND DGND 1 6 13 AD71056 POWER SUPPLY MONITOR SIGNAL PROCESSING BLOCK V2P 2 + ...110101... Σ-Δ V2N ADC 3 MULTIPLIER PHASE CORRECTION LPF V1N 4 ...11011001... Σ-Δ Ф ADC HPF V1P 5 + INTERNAL DIGITAL-TO-FREQUENCY OSCILLATOR CONVERTER 2.5V 4kΩ REFERENCE
01 0 6- 63
7 11 8 10 9 12 14 16 15
05
REF RCLKIN SCF S0 S1 REVP IN/OUT CF F1 F2
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 license is granted by implication or otherwise under any patent or patent rights of Analog Devices. Tel: 781.329.4700 www.analog.com Trademarks and registered trademarks are the property of their respective owners. Fax: 781.461.3113 ©2006 Analog Devices, Inc. All rights reserved.
Document Outline FEATURES GENERAL DESCRIPTION FUNCTIONAL BLOCK DIAGRAM TABLE OF CONTENTS REVISION HISTORY SPECIFICATIONS TIMING CHARACTERISTICS Timing Diagram ABSOLUTE MAXIMUM RATINGS ESD CAUTION TERMINOLOGY PIN CONFIGURATION AND FUNCTION DESCRIPTIONS TYPICAL PERFORMANCE CHARACTERISTICS THEORY OF OPERATION POWER FACTOR CONSIDERATIONS NONSINUSOIDAL VOLTAGE AND CURRENT APPLICATIONS ANALOG INPUTS Channel V1 (Current Channel) Channel V2 (Voltage Channel) Typical Connection Diagrams POWER SUPPLY MONITOR HPF and Offset Effects Digital-to-Frequency Conversion Connecting to a Microcontroller for Energy Measurement Power Measurement Considerations INTERNAL OSCILLATOR (OSC) TRANSFER FUNCTION Frequency Outputs F1 and F2 Frequency Output CF SELECTING A FREQUENCY FOR AN ENERGY METER APPLICATION Frequency Outputs NO LOAD THRESHOLD NEGATIVE POWER INFORMATION OUTLINE DIMENSIONS ORDERING GUIDE