Datasheet ADE7854A, ADE7858A, ADE7868A, ADE7878A (Analog Devices)

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Polyphase Multifunction Energy Metering IC Data Sheet ADE7854A/ ADE7858A/ ADE7868A/ ADE7878A FEATURES
The ADE7878A can also perform fundamental-only active and
Highly accurate; supports EN 50470-1, EN 50470-3,
reactive energy measurement and rms calculations. A fixed function
IEC 62053-21, IEC 62053-22, and IEC 62053-23 standards
digital signal processor (DSP) executes the signal processing. The
Compatible with 3-phase, 3- or 4-wire (delta or wye) meters,
DSP program is stored in the internal ROM memory.
and other 3-phase services
The ADE7854A/ADE7858A/ADE7868A/ADE7878A can
Supplies total (fundamental and harmonic) active, reactive,
measure active, reactive, and apparent energy in various 3-phase
and apparent energy and fundamental active/reactive
configurations, such as wye or delta services, with both three and
energy on each phase and on the overall system
four wires. Aside from regular rms measurements, which are
0.1% error (typical) in active and reactive energy over a
updated every 8 kHz, these devices measure low ripple rms values,
dynamic range of 1000 to 1 at TA = 25°C
which are averaged internally and updated every 1.024 sec. The
0.2% error (typical) in active and reactive energy over a
devices provide system calibration features for each phase, that
dynamic range of 3000 to 1 at TA = 25°C
is, rms offset correction, phase calibration, and gain calibration.
Averaged rms measurements available in low ripple rms
The CF1, CF2, and CF3 logic outputs provide a wide selection
registers
of power information. All four devices provide total active and
Supports current transformer and di/dt current sensors
apparent powers, as well as the sum of the current rms values;
Dedicated ADC channel for neutral current input
the ADE7858A, ADE7868A, and ADE7878A also provide total
Estimated neutral current measurement by calculating the
reactive powers; whereas the ADE7878A provides fundamental
rms of the sum of the phase currents in all 3 phases
active and reactive powers.
0.1% error (typical) in voltage and current rms over a dynamic range of 1000 to 1 at T
The ADE7854A/ADE7858A/ADE7868A/ADE7878A contain
A = 25°C Supplies sampled waveform data on all 3 phases and on
waveform sampling registers that al ow access to al ADC outputs.
neutral current
The devices also incorporate power quality measurements, such
Selectable no load thresholds for total and fundamental
as short duration low or high voltage detection, short duration
active and reactive powers, as well as for apparent powers
high current variation, line voltage period measurement, and
Highly accurate low power battery mode phase current
angles between phase voltages and currents.
monitoring for antitampering detection
Two serial interfaces, serial peripheral interface (SPI) and I2C,
Battery supply input for missing neutral operation
can communicate with the devices. A dedicated high speed
Phase angle measurements in current and voltage channels
interface, the high speed data capture (HSDC) port, can be used
Calibration frequency (CF) output directly drives LED and
in conjunction with I2C to provide access to the ADC outputs
opto-isolators
and real-time power information.
Reference: 1.2 V (drift of ±5 ppm/°C typical) with external overdrive capability
The devices have two interrupt request pins, IRQ0 and IRQ1,
Single 3.3 V supply
to indicate that an enabled interrupt event has occurred. For the
40-lead, Pb-free lead frame chip scale package (LFCSP)
ADE7868A/ADE7878A, three specially designed low power
Operating temperature: −40°C to +85°C
modes ensure the continuity of energy accumulation when the
Flexible I2C, SPI, and HSDC serial interfaces
ADE7868A/ADE7878A are in a tampering situation.
GENERAL DESCRIPTION
Table 1 lists each device and its functions. These devices are available in 40-lead, Pb-free LFCSP packages. The ADE7854A/ADE7858A/ADE7868A/ADE7878A are high accuracy, 3-phase electrical energy measurement ICs with serial
Table 1. Device Comparison
interfaces and three flexible pulse outputs. The devices incorporate
Tamper
second-order Σ-∆ analog-to-digital converters (ADCs), a digital
I RMS, Fundamental Detect and V RMS, WATT and Low Power
integrator, reference circuitry, and all signal processing required
Part No. WATT VAR and VA di/dt VAR Modes
to perform total (fundamental and harmonic) active, reactive ADE7854A Yes No Yes Yes No No (ADE7858A, ADE7868A, and ADE7878A), and apparent energy ADE7858A Yes Yes Yes Yes No No measurement and rms calculations. ADE7868A Yes Yes Yes Yes No Yes ADE7878A Yes Yes Yes Yes Yes Yes
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Document Outline FEATURES GENERAL DESCRIPTION TABLE OF CONTENTS REVISION HISTORY FUNCTIONAL BLOCK DIAGRAMS SPECIFICATIONS TIMING CHARACTERISTICS I2C Interface Timing SPI Interface Timing HSDC Interface Timing Load Circuit for Timing Specifications ABSOLUTE MAXIMUM RATINGS THERMAL RESISTANCE ESD CAUTION PIN CONFIGURATION AND FUNCTION DESCRIPTIONS TYPICAL PERFORMANCE CHARACTERISTICS TEST CIRCUIT TERMINOLOGY POWER MANAGEMENT PSM0 NORMAL POWER MODE (ALL DEVICES) PSM1 REDUCED POWER MODE (ADE7868A AND ADE7878A ONLY) PSM2 LOW POWER MODE (ADE7868A AND ADE7878A ONLY) PSM2 Interrupt Mode (Default) Setting the Measurement Period Setting the Threshold PSM2 IRQ1/ Only Mode PSM3 SLEEP MODE (ALL DEVICES) POWER-UP PROCEDURE HARDWARE RESET SOFTWARE RESET THEORY OF OPERATION ANALOG INPUTS ANALOG-TO-DIGITAL CONVERSION Antialiasing Filter ADC Transfer Function CURRENT CHANNEL ADC Current Waveform Gain Registers Current Channel High-Pass Filter Current Channel Sampling di/dt CURRENT SENSOR AND DIGITAL INTEGRATOR VOLTAGE CHANNEL ADC Voltage Waveform Gain Registers Voltage Channel HPF Voltage Channel Sampling CHANGING THE PHASE VOLTAGE DATAPATH POWER QUALITY MEASUREMENTS Zero-Crossing Detection Zero-Crossing Timeout Phase Sequence Detection Time Interval Between Phases Delays Between Voltages and Currents Delays Between Phase Voltages Delays Between Phase Currents Power Factor Period Measurement Phase Voltage Sag Detection Sag Level Set Peak Detection Overvoltage and Overcurrent Detection Overvoltage and Overcurrent Level Set Neutral Current Mismatch—ADE7868A and ADE7878A PHASE COMPENSATION REFERENCE CIRCUIT DIGITAL SIGNAL PROCESSOR ROOT MEAN SQUARE MEASUREMENT Current RMS Calculation Low Ripple Current RMS Current RMS Offset Compensation Current Mean Absolute Value Calculation—ADE7868A and ADE7878A Only Current MAV Gain and Offset Compensation Voltage RMS Calculation Low Ripple Voltage RMS Voltage RMS Offset Compensation Voltage RMS in 3-Phase, 3-Wire Delta Configurations ACTIVE POWER CALCULATION Total Active Power Calculation Fundamental Active Power Calculation—ADE7878A Only Active Power Gain Calibration Active Power Offset Calibration Sign of Active Power Calculation Active Energy Calculation Integration Time Under Steady Load Energy Accumulation Modes Line Cycle Active Energy Accumulation Mode REACTIVE POWER CALCULATION—ADE7858A, ADE7868A, ADE7878A ONLY Reactive Power Gain Calibration Reactive Power Offset Calibration Sign of Reactive Power Calculation Reactive Energy Calculation Integration Time Under Steady Load Energy Accumulation Modes Line Cycle Reactive Energy Accumulation Mode APPARENT POWER CALCULATION Apparent Power Gain Calibration Apparent Power Offset Calibration Apparent Power Calculation Using VNOM Apparent Energy Calculation Integration Time Under Steady Load Energy Accumulation Mode Line Cycle Apparent Energy Accumulation Mode WAVEFORM SAMPLING MODE ENERGY TO FREQUENCY CONVERSION Synchronizing Energy Registers with the CFx Outputs CFx Outputs for Various Accumulation Modes Sign of Sum-of-Phase Powers in the CFx Datapath NO LOAD CONDITION No Load Detection Based on Total Active and Reactive Powers No Load Detection Based on Fundamental Active and Reactive Powers—ADE7878A Only No Load Detection Based on Apparent Power CHECKSUM REGISTER INTERRUPTS Using the Interrupts with an MCU APPLICATIONS INFORMATION QUICK SETUP OF DEVICES AS ENERGY METERS CRYSTAL CIRCUIT LAYOUT GUIDELINES ADE7878A EVALUATION BOARD DIE VERSION SILICON ANOMALY ADE7854A/ADE7858A/ADE7868A/ADE7878A FUNCTIONALITY ISSUES FUNCTIONALITY ISSUES SERIAL INTERFACES SERIAL INTERFACE SELECTION COMMUNICATION VERIFICATION I2C-COMPATIBLE INTERFACE I2C Write Operation I2C Read Operation SPI-COMPATIBLE INTERFACE SPI Write Operation SPI Read Operation SPI Burst Read Operation HSDC INTERFACE REGISTER LIST OUTLINE DIMENSIONS ORDERING GUIDE