ade7768 Analog Devices, Inc., ade7768 Datasheet
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ade7768 Summary of contents
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... IEC61036 (equivalent to IEC62053-21) low cost, watt-hour meter reference design. The only analog circuitry used in the ADE7768 is in the Σ-Δ ADCs and reference circuit. All other signal processing, such as multiplication and filtering, is carried out in the digital domain. ...
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... ADE7768 TABLE OF CONTENTS Specifications..................................................................................... 3 Timing Characteristics ................................................................ 4 Absolute Maximum Ratings............................................................ 5 ESD Caution.................................................................................. 5 Terminology ...................................................................................... 6 Pin Configuration and Function Descriptions............................. 7 Typical Performance Characteristics ............................................. 8 Functional Description .................................................................. 10 Theory of Operation .................................................................. 10 Analog Inputs.............................................................................. 11 Revision History 8/05—Sp0 to Rev. A Power Supply Monitor ............................................................... 12 Internal Oscillator (OSC).......................................................... 14 Transfer Function....................................................................... 14 Selecting a Frequency for an Energy Meter Application ...... 15 No-Load Threshold ...
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... SOURCE 0.5 V max 4 V min I SOURCE 0.5 V max ±10 % ideal typ External 2.5 V reference 21.2 mV rms 116.7 mV rms Rev Page ADE7768 −40°C to +85°C, MIN MAX of 200 mV rms @ 100 ± 250 ± ± mA, V ...
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... ADE7768 Parameter POWER SUPPLY See the Terminology section for an explanation of specifications. 2 See the figures in the Typical Performance Characteristics section. 3 Sample tested during initial release and after any redesign or process change that may affect this parameter. TIMING CHARACTERISTICS ± 5%, AGND = DGND = 0 V, on-chip reference, RCLKIN = 6.2 kΩ, 0.5% ± 50 ppm/° unless otherwise noted ...
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... maximum rating conditions for extended periods may affect −0 0.3 V device reliability. DD −0 0 −0 0 −40°C to +85°C −65°C to +150°C 150°C 350 mW 124.9°C/W See J-STD-20 Rev Page ADE7768 ...
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... The ideal frequency is obtained from the ADE7768 transfer function. Gain Error The gain error of the ADE7768 is defined as the difference between the measured output of the ADCs (minus the offset) and the ideal output of the ADCs. The difference is expressed as a percentage of the ideal of the ADCs ...
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... AGND This pin provides the ground reference for the analog circuitry in the ADE7768, that is, the 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, current and voltage sensors, and so forth. ...
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... CURRENT CHANNEL (% of Full Scale) Figure 6. Error Reading over Temperature with On-Chip Reference (PF = 0.5 IND 100nF 602kΩ V2P 2 150nF 200Ω ADE7768 CF 14 200Ω 3 V2N 150nF 40mA REVP 12 200Ω 6.2kΩ 5 V1P + RCLKIN 11 150nF 200Ω ...
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... MEAN = 0% SDs = 1.55% MIN = –11.79% 800 MAX = +6.08% NO. OF POINTS = 3387 600 400 200 0 100 –10 –8 –6 Figure 14. Part-to-Part CF Deviation from Mean Rev Page ADE7768 EXTERNAL REFERENCE TEMPERATURE = 25° CHANNEL V1 OFFSET (mV) EXTERNAL REFERENCE TEMPERATURE = 25°C – ...
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... ADE7768 FUNCTIONAL DESCRIPTION THEORY OF OPERATION The two ADCs in the ADE7768 digitize the voltage signals from the current and voltage sensors. These ADCs are 16-bit Σ-Δs with an oversampling rate of 450 kHz. This analog input structure greatly simplifies sensor interfacing by providing a wide dynamic range for direct connection to the sensor and by simplifying the antialiasing filter design ...
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... ANALOG INPUTS Channel V1 (Current Channel) The voltage output from the current sensor is connected to the ADE7768 here. Channel fully differential voltage input. V1P is the positive input with respect to V1N. The maximum peak differential signal on Channel V1 should be less than ±30 mV (21 mV rms for a pure sinusoidal signal) ) for specified operation ...
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... The ADE7768 contains an on-chip power supply monitor. The power supply ( continuously monitored by the DD ADE7768. If the supply is less than 4 V, the ADE7768 becomes inactive. This is useful to ensure proper device operation at power-up and power-down. The power supply monitor has built-in hysteresis and filtering, which provide a high degree of immunity to false triggering from noisy supplies ...
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... The accumulation of the signal suppresses or averages out any non-dc components in the instantaneous positive-only real power signal. The average value of a sinusoidal signal is 0. Thus, the frequency generated by the ADE7768 is proportional to the average positive-only real power. Figure 26 shows the digital-to- frequency conversion for steady load conditions, that is, the constant voltage and current ...
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... ADE7768 output frequency is running asynchro- nously to the MCU timer. This results in a 1-in- error in the power measurement. When REVP is logic high, the ADE7768 does not generate any pulse on F1, F2, and CF. INTERNAL OSCILLATOR (OSC) The nominal internal oscillator frequency is 450 kHz when used with RCLKIN, with a nominal value of 6.2 kΩ ...
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... Frequency on F1 and F2— F (Hz) CH1 and CH2 Half-Scale AC Input 1–4 0.86 0.044 Hz 0.051 × 1.72 0.051 × F 0.088 Hz 2 3.43 0.051 × F 0.176 Hz 3 6.86 0.051 × F 0.352 Hz 4 ADE7768 1 1 ...
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... NO-LOAD THRESHOLD The ADE7768 includes a no-load threshold and start-up current feature that eliminates any creep effects in the meter. The ADE7768 is designed to issue a minimum output frequency. Any load generating a frequency lower than this minimum frequency does not cause a pulse to be issued on F1, F2 ...
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... REFERENCE ONLY AND ARE NOT APPROPRIATE FOR USE IN DESIGN ORDERING GUIDE Model Temperature Range ADE7768AR −40°C to +85°C ADE7768AR-RL −40°C to +85°C 1 ADE7768ARZ −40°C to +85°C 1 ADE7768ARZ-RL −40°C to +85°C ADE7768AR-REF EVAL-ADE7768EB Pb-free part. 10.00 (0.3937) 9.80 (0.3858 6.20 (0.2441) 4.00 (0.1575) 5.80 (0.2283) 3.80 (0.1496 1.75 (0.0689) 1.27 (0.0500) BSC 1 ...
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... ADE7768 NOTES Rev Page ...
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... NOTES Rev Page ADE7768 ...
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... ADE7768 NOTES © 2005 Analog Devices, Inc. All rights reserved. Trademarks and registered trademarks are the property of their respective owners. D05331–0–8/05(A) Rev Page ...