ADE7878ACPZ Analog Devices Inc, ADE7878ACPZ Datasheet - Page 26

• 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

ADE7878
Current Waveform Gain Registers
There is a multiplier in the signal path of each phase and
neutral current. The current waveform can be changed by
±100% by writing a correspondent twos complement number to
the 24-bit signed current waveform gain registers (AIGAIN[23:0],
BIGAIN[23:0], CIGAIN[23:0], and NIGAIN[23:0]). For
example, if 0x400000 is written to those registers, the ADC
output is scaled up by 50%. To scale the input by −50%, write
0xC00000 to the registers. Equation 3 describes mathematically
the function of the current waveform gain registers.
Changing the content of AIGAIN[23:0], BIGAIN[23:0],
CIGAIN[23:0], or INGAIN[23:0] affects all calculations based
on its current; that is, it affects the corresponding phase active/
reactive/apparent energy and current rms calculation. In
addition, waveform samples scale accordingly.
Note that the serial ports of the ADE7878 work on 32-, 16-, or
8-bit words, and the DSP works on 28 bits. The 24-bit AIGAIN,
BIGAIN, CIGAIN, and NIGAIN registers are accessed as 32-bit
Current Waveform =
ADC
V
+0.5V/GAIN
–0.5V/GAIN
IN
IAN
IAP
Output
×1, ×2, ×4, ×8, ×16
PGA1
0V
V
PGA1 BITS
GAIN[2:0]
IN
×
ANALOG INPUT RANGE
⎛
⎜ ⎜
⎝
1
V
IN
+
INP
INN
Content
REFERENCE
PGA2
×1, ×2, ×4, ×8, ×16
ADC
PGA2 BITS
GAIN[5:3]
of
Current
0xA58AC0 =
2
0x5A7540 =
DSP
AIGAIN[23:0]
+5,928,256
–5,928,256
23
Gain
REFERENCE
0V
ADC
Register
ANALOG OUTPUT RANGE
CURRENT CHANNE L
HPFDIS
[23:0]
Figure 30. Current Channel Signal Path
HPF
Figure 31. Neutral Current Signal Path
DATA RANGE
DSP
NIGAIN[23:0]
⎞
⎟ ⎟
⎠
Rev. 0 | Page 26 of 92
(3)
INTEGRATOR
CONFIG[0]
INTEN BIT
DIGITAL
HPF
registers with the four most significant bits (MSBs) padded with
0s and sign extended to 28 bits. See Figure 32 for details.
Current Channel HPF
The ADC outputs can contain a dc offset. This offset can create
errors in power and rms calculations. High-pass filters (HPFs)
are placed in the signal path of the phase and neutral currents
and of the phase voltages. If enabled, the HPF eliminates any dc
offset on the current channel. All filters are implemented in the
DSP and, by default, they are all enabled: the 24-bit HPFDIS[23:0]
register is cleared to 0x00000000. All filters are disabled by
setting HPHDIS[23:0] to any non zero value.
As previously stated, the serial ports of the ADE7878 work on
32-, 16- or 8-bit words. The HPFDIS register is accessed as a
32-bit register with eight MSBs padded with 0s. See Figure 33
for details.
0xA58AC0 =
0x5A7540 =
+5,928,256
–5,928,256
INTEGRATOR
CURRENT PEAK,
OVERCURRENT
DETECT
CURRENT RMS (IRMS)
CALCULATION
IAWV WAVEFORM
SAMPLE REGISTER
TOTAL/FUNDAMENTAL
ACTIVE AND REACTIVE
POWER CALCULATION
LPF1
CONFIG[0]
INTEN BIT
Figure 33. 24-Bit HPFDIS Register Transmitted as 32-Bit Word
DIGITAL
31
31
Figure 32. 24-Bit xIGAIN Transmitted as 32-Bit Words
0V
0000
0000
ZX DETECTION
CURRENT CHANNE L
DATA RANGE AFTER
28 27
EQUAL TO BIT 23
BITS[27:24] ARE
INTEGRATION
0000
CURRENT RMS (IRMS)
CALCULATION
INWV WAVEFORM
SAMPLE REGISTER
0xA58AC0 =
24 23
24
0x5A7540 =
+5,928,256
–5,928,256
23
BIT 23 IS A SIGN BIT
0V
24-BIT NUMBER
24-BIT NUMBER
ZX SIGNAL
DATA RANGE
0
0