ADE7878ACPZ Analog Devices Inc, ADE7878ACPZ Datasheet - Page 54

• Manufacturer Part Number: ADE7878ACPZ
• Description: IC ENERGY METERING 3PH 40LFCSP
• Manufacturer: Analog Devices Inc

Specifications of ADE7878ACPZ

• Input Impedance: 400 KOhm
• Measurement Error: 0.1%
• Voltage - I/o High: 2.4V
• Voltage - I/o Low: 0.4V
• Current - Supply: 22mA
• Voltage - Supply: 3 V ~ 3.6 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 40-WFQFN, CSP Exposed Pad
• Meter Type: 3 Phase
• Supply Voltage Range: 3V To 3.6V
• Operating Temperature Range: -40°C To +85°C
• Digital Ic Case Style: LFCSP
• No. Of Pins: 40
• Msl: MSL 1 - Unlimited
• Peak Reflow Compatible (260 C): Yes
• Supply Voltage Min: 3V
• Rohs Compliant: Yes
• Leaded Process Compatible: Yes
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

ADE7854/ADE7858/ADE7868/ADE7878
APPARENT POWER CALCULATION
Apparent power is defined as the maximum power that can be
delivered to a load. One way to obtain the apparent power is by
multiplying the voltage rms value by the current rms value (also
called the arithmetic apparent power)
where:
S is the apparent power.
V rms and I rms are the rms voltage and current, respectively.
The ADE7854/ADE7858/ADE7868/ADE7878 compute the
arithmetic apparent power on each phase. Figure 68 illustrates
the signal processing in each phase for the calculation of the
apparent power in the ADE78xx. Because V rms and I rms con-
tain all harmonic information, the apparent power computed by
the ADE78xx is total apparent power. The ADE7878 does not
compute fundamental apparent power because it does not measure
the rms values of the fundamental voltages and currents.
S = V rms × I rms
AVRMS
AIRMS
Figure 68. Apparent Power Data Flow and Apparent Energy Accumulation
AVAGAIN
2
4
AVA
DIGITAL SIGNAL PROCESSOR
(39)
Rev. D | Page 54 of 96
ACCUMULATOR
VATHR[47:0]
The ADE7854/ADE7858/ADE7868/ADE7878 store the instan-
taneous phase apparent powers into the AVA, BVA, and CVA
registers. Their expression is
where:
U, I are the rms values of the phase voltage and current.
U
the ADC inputs are at full scale.
PMAX = 33,516,139, the instantaneous power computed when
the ADC inputs are at full scale and in phase.
The xVA[23:0] waveform registers may be accessed using
various serial ports. Refer to the Waveform Sampling Mode
section for more details.
The ADE7854/ADE7858/ADE7868/ADE7878 can compute the
apparent power in an alternative way by multiplying the phase
rms current by an rms voltage introduced externally. See the
Apparent Power Calculation Using VNOM section for details.
FS
, I
FS
xVA
are the rms values of the phase voltage and current when
=
U
U
FS
×
32-BIT REGISTER
I
I
FS
AVAHR[31:0]
×
PMAX
×
2
1
4
(40)