ADE7854AACPZ View Datasheet(PDF) - Analog Devices
Part Name
Description
MFG CO.
'ADE7854AACPZ' PDF : 96 Pages View PDF
ADE7854A/ADE7858A/ADE7868A/ADE7878A
Data Sheet
TERMINOLOGY
Measurement Error
The error associated with the energy measurement made by
the ADE7854A/ADE7858A/ADE7868A/ADE7878A is defined
as follows:
Measurement Error =
Energy Registered by Device − True Energy ×100%
(1)
True Energy
where Device represents the ADE7854A, ADE7858A,
ADE7868A, or ADE7878A.
Power Supply Rejection (PSR)
PSR quantifies the ADE7854A/ADE7858A/ADE7868A/
ADE7878A measurement error as a percentage of reading when
the power supplies are varied. For the ac PSR measurement, a
reading at nominal supplies (3.3 V) is taken. A second reading
is obtained with the same input signal levels when an ac signal
(120 mV rms at twice the fundamental frequency) is introduced
onto the supplies. Any error introduced by this ac signal is
expressed as a percentage of reading.
For the dc PSR measurement, a reading at nominal supplies
(3.3 V) is taken. A second reading is obtained with the same input
signal levels when the power supplies are varied by ±10%. Any
error introduced is expressed as a percentage of the reading.
ADC Offset
ADC offset refers to the dc offset associated with the analog
inputs to the ADCs. It means that with the analog inputs
connected to AGND, the ADCs still see a dc analog input signal.
The magnitude of the offset depends on the gain and input range
selection. The high-pass filter (HPF) removes the offset from the
current and voltage channels; therefore, the power calculation
remains unaffected by this offset.
Gain Error
The gain error in the ADCs of the ADE7854A/ADE7858A/
ADE7868A/ADE7878A is defined as the difference between the
measured ADC output code (minus the offset) and the ideal output
code (see the Current Channel ADC and Voltage Channel ADC
sections). The difference is expressed as a percentage of the
ideal code.
CF Jitter
The period of pulses at one of the CF1, CF2, or CF3/HSCLK
pins is continuously measured. The maximum, minimum, and
average values of four consecutive pulses are computed, as
follows:
Maximum = max(Period0, Period1, Period2, Period3)
Minimum = min(Period0, Period1, Period2, Period3)
Average = Period0 + Period1 + Period2 + Period3
4
The CF jitter is then computed as follows:
CFJITTER
=
Maximum − Minimum
Average
× 100%
(2)
Signal-to-Noise Ratio (SNR)
SNR is the ratio of the rms value of the actual input signal
to the rms sum of all other spectral components below 2 kHz,
excluding harmonics and dc. The input signal contains only
the fundamental component. The spectral components are
calculated over a 2 sec window. The value for SNR is expressed
in decibels.
Signal-to-Noise-and-Distortion (SINAD) Ratio
SINAD is the ratio of the rms value of the actual input signal
to the rms sum of all other spectral components below 2 kHz,
including harmonics but excluding dc. The input signal contains
only the fundamental component. The spectral components are
calculated over a 2 sec window. The value for SINAD is expressed
in decibels.
Rev. C | Page 20 of 96
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