ade7761a Analog Devices, Inc., ade7761a Datasheet
ade7761a
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ade7761a Summary of contents
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... The part specifications surpass the accuracy requirements as quoted in the IEC 62053-21 standard. The only analog circuitry used on the ADE7761A 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 extremes in environmental conditions and over time ...
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... ADE7761A TABLE OF CONTENTS Features .............................................................................................. 1 General Description ......................................................................... 1 Functional Block Diagram .............................................................. 1 Revision History ............................................................................... 2 Specifications..................................................................................... 3 Timing Characteristics ................................................................ 4 Absolute Maximum Ratings............................................................ 5 Performance Issues That May Affect Billing Accuracy........... 5 ESD Caution.................................................................................. 5 Pin Configuration and Function Descriptions............................. 6 Terminology ...................................................................................... 8 Typical Performance Characteristics ............................................. 9 Test Circuit ...................................................................................... 10 Operation......................................................................................... 11 Power Supply Monitor ............................................................... 11 REVISION HISTORY 7/06— ...
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... Rev Page ADE7761A = −40°C to +85°C. MAX = V = ±100 mV rms ±100 mV rms 2P active active , V − − ...
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... ADE7761A Parameter 5 LOGIC INPUTS PGA, SCF, S1, and S0 Input High Voltage, V INH Input Low Voltage, V INL Input Current Input Capacitance LOGIC OUTPUTS CF, REVP, and FAULT Output High Voltage Output Low Voltage and F2 Output High Voltage Output Low Voltage, V ...
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... Billing active energy in Case 1 is consistent with the understanding of the quantity represented by pulses on CF, F1, and F2 outputs (watt-hour). • Billing active energy while the ADE7761A is in Case 2 must be decided knowing that the entity measured by the ADE7761A in this case is ampere-hour and not watt-hour. ...
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... AGND This pin provides the ground reference for the analog circuitry in the ADE7761A, that is, ADCs and reference. This pin should be tied to the analog ground plane of the PCB. The analog ground plane is the ground reference for all analog circuitry, such as antialiasing filters, and current and voltage transducers. For good noise suppression, the analog ground plane should be connected only to the digital ground plane at the DGND pin ...
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... DGND This pin provides the ground reference for the digital circuitry in the ADE7761A, that is, multiplier, filters, and digital-to-frequency converters. This pin should be tied to the digital ground plane of the PCB. The digital ground plane is the ground reference for all digital circuitry, such as counters (mechanical and digital), MCUs, and indicator LEDs ...
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... Gain Error The gain error in the ADE7761A ADCs is defined as the difference between the measured output frequency (minus the offset) and the ideal output frequency measured with a ...
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... Figure 8. Active Power Error as a Percentage of Reading over Power Supply with Gain = 1 and Internal Reference ON-CHIP REFERENCE +85°C 0 +25°C –40°C 0.1 1.0 10.0 CURRENT (% of Full Scale) Figure 9. Ampere Hour Error as a Percentage of Reading in Missing Neutral Mode with Gain = 1 and Internal Reference ADE7761A 100 100.0 100.0 ...
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... ADE7761A TEST CIRCUIT 40A TO 80mA 18Ω 1MΩ 220V 1kΩ 33nF 10µF 100nF 1kΩ 33nF ADE7761A 1kΩ FAULT RB 33nF RCLKIN 1kΩ 33nF 1kΩ 33nF S1 SCF REF V 6 IN/OUT 2P 560kΩ MISCAL 7 100kΩ ...
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... The ADE7761A continuously monitors the power supply (V with its on-chip, power supply monitor. If the supply is less than 4 V ± 5%, the ADE7761A goes into an inactive state, that is, no energy is accumulated and the CF, F1, and F2 outputs are disabled. This is useful to ensure correct device operation at power-up and during power-down ...
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... The first option uses a potential transformer (PT) to provide complete isolation from the main voltage. In the second option, the ADE7761A is biased around the neutral wire, and a resistor divider is used to provide a voltage signal that is proportional to the line voltage. Adjusting the ratio of RA and convenient way to carry out a gain calibration on the meter ...
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... The first is oversampling, which means that the signal is sampled at a rate (frequency) that is many times higher than the bandwidth of interest. For example, the sampling rate in the ADE7761A is CLKIN (450 kHz) and the band of interest kHz. Oversampling has the effect of spreading the quantization noise (noise due to sampling) over a wider bandwidth ...
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... TIME Figure 22. Signal Processing Block Diagram The low frequency output of the ADE7761A is generated by accumulating this active power information. This low frequency inherently means a long accumulation time between output pulses. The output frequency is, therefore, proportional to the average active power. This average active power information can, in turn, be accumulated (for example counter) to generate active energy information ...
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... This problem is easily avoided in the ADE7761A with the HPF in Channel 1. By removing the offset from at least one channel, no error component can be generated the multiplication. Error terms at cos(ωt) are removed by the LPF and the digital-to-frequency conversion (see the Digital-to-Frequency Conversion section) ...
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... F1 frequency output. TRANSFER FUNCTION Frequency Outputs F1 and The ADE7761A calculates the product of two voltage signals TIME (on Channel 1 and Channel 2) and then low-pass filters this FOUT product to extract active power information. This active power CF information is then converted to a frequency. The frequency information is output on F1 and F2 in the form of active high pulses ...
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... A fault is indicated when these currents differ by more than 6.25%. However, even during a fault, the output pulse rate on F1 and F2 is generated using the larger of the two currents. Because the ADE7761A looks for a difference between the voltage signals on V important that both current transducers be closely matched. ...
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... A COMPARE TO The ADE7761A integrates a novel fault detection that warns MULTIPLIER and allows the ADE7761A to continue to bill in case a meter is B connected to only one wire (see Figure 31). For correct operation of the ADE7761A in this mode, the V ADE7761A must be maintained within the specified range (5 V ± 5%). The missing neutral detection algorithm is designed to work over a line frequency ...
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... Billing active energy in Case 1 is consistent with the V understanding of the quantity represented by pulses on CF F1, and F2 outputs (watt-hour • Billing active energy while the ADE7761A is in Case 2 must decided knowing that the entity measured by the C ADE7761A in this case is ampere-hour and not watt-hour. ...
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... In missing neutral mode, the ac voltage of ±330 mV peak is applied to V1, no signal is connected on V2, and a 330 mV dc and F (Hz input is applied to MISCAL. With the ADE7761A in the same configuration as the previous example, the expected output frequencies on CF Frequency = F Rev Page 1.7 Hz, SCF = 1– ...
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... APPLICATIONS INTERFACING TO A MICROCONTROLLER FOR ENERGY MEASUREMENT The easiest way to interface the ADE7761A to a microcontroller is to use the CF high frequency output with the output frequency scaling set to 2048 × F1, F2. This is done by setting SCF = 0 and (see Table 8). With full-scale ac signals on the analog inputs, the output frequency approximately 5 ...
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... Note that the no-load threshold is not enabled when using the high CF frequency mode: SCF = NEGATIVE POWER INFORMATION The ADE7761A detects when the current and voltage channels have a phase shift greater than 90 ° . This mechanism can detect a wrong connection of the meter or the generation of negative power ...
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... OUTLINE DIMENSIONS 2.00 MAX 0.05 MIN COPLANARITY 0.10 ORDERING GUIDE Model Temperature Range ADE7761AARS –40°C to +85°C ADE7761AARS-RL –40°C to +85°C 1 ADE7761AARSZ –40°C to +85°C 1 ADE7761AARSZ-RL –40°C to +85°C ADE7761AARS-REF Pb-free part. 7.50 7.20 6. 5.60 5.30 8.20 5.00 7.80 7. 1.85 1.75 1.65 8° 0.38 SEATING 4° 0.22 PLANE 0° ...
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... ADE7761A NOTES ©2006 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. D05040-0-7/06(0) Rev Page ...