ADE7768ARZ-RL Analog Devices Inc, ADE7768ARZ-RL Datasheet - Page 15

• Manufacturer Part Number: ADE7768ARZ-RL
• Description: IC,Power Metering,CMOS,SOP,16PIN,PLASTIC
• Manufacturer: Analog Devices Inc

Specifications of ADE7768ARZ-RL

• Input Impedance: 320 KOhm
• Measurement Error: 0.1%
• Voltage - I/o High: 2.4V
• Voltage - I/o Low: 0.8V
• Current - Supply: 5mA
• Voltage - Supply: 4.75 V ~ 5.25 V
• Operating Temperature: -40°C ~ 85°C
• Mounting Type: Surface Mount
• Package / Case: 16-SOIC (0.154", 3.90mm Width)
• Meter Type: Single Phase
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

Table 5. F
S1
0
0
1
1
1
2
Example
In this example, with ac voltages of ±30 mV peak applied to
V1 and ±165 mV peak applied to V2, the expected output
frequency is calculated as follows:
F
V1
V2
V
Note that if the on-chip reference is used, actual output
frequencies may vary from device to device due to the
reference tolerance of ±200 mV.
Table 6. Maximum Output Frequency on F1 and F2
S1
0
0
1
1
1
Frequency Output CF
The pulse output CF (calibration frequency) is intended for
calibration purposes. The output pulse rate on CF can be up
to 2048 times the pulse rate on F1 and F2. The lower the F
frequency selected, the higher the CF scaling (except for the
high frequency mode SCF = 0, S1 = S0 = 1). Table 7 shows
how the two frequencies are related, depending on the states
of the logic inputs S0, S1, and SCF. Due to its relatively high
pulse rate, the frequency at the CF logic output is proportional
to the instantaneous positive-only real power. As with F1 and
F2, CF is derived from the output of the low-pass filter after
multiplication. However, because the output frequency is
high, this positive-only real power information is accumulated
over a much shorter time. Therefore, less averaging is carried
out in the digital-to-frequency conversion. With much less
averaging of the positive-only real power signal, the CF output
is much more responsive to power fluctuations (see the signal
processing block diagram in Figure 15).
F
Values are generated using the nominal frequency of 450 kHz.
Values are generated using the nominal frequency of 450 kHz.
1–4
REF
1–4
Freq
rms
rms
= OSC/2
is a binary fraction of the internal oscillator frequency.
= 2.45 V (nominal reference value)
= 0.03/√2 V
= 0.165/√2 V
S0
0
1
0
1
=
S0
0
1
0
1
494
1–4
OSC Relation
0.204 × F
0.204 × F
0.204 × F
0.204 × F
19
.
Frequency Selection
75
Hz, S0 = S1 = 0
2
OSC Relation
OSC/2
OSC/2
OSC/2
OSC/2
×
×
. 0
03
2
1
2
3
4
×
19
18
17
16
×
. 0
. 2
165
45
2
×
Max Frequency
0.175
0.35
0.70
1.40
1
F
1
=
F
0.86
1.72
3.43
6.86
. 0
1–4
204
at Nominal OSC (Hz)
×
F
1
1
=
or AC Inputs (Hz)
. 0
175
(11)
1–4
Rev. A | Page 15 of 20
2
Table 7. Maximum Output Frequency on CF
SCF
1
0
1
0
1
0
1
0
1
SELECTING A FREQUENCY FOR AN ENERGY
METER APPLICATION
As shown in Table 5, the user can select one of four frequencies.
This frequency selection determines the maximum frequency
on F1 and F2. These outputs are intended for driving an energy
register (electromechanical or other). Because only four
different output frequencies can be selected, the available
frequency selection has been optimized for a meter constant
of 100 imp/kWh with a maximum current of between 10 A
and 120 A. Table 8 shows the output frequency for several
maximum currents (I
cases, the meter constant is 100 imp/kWh.
Table 8. F1 and F2 Frequency at 100 imp/kWh
I
12.5
25.0
40.0
60.0
80.0
120.0
The F
output frequencies (F1, F2). When designing an energy meter,
the nominal design voltage on Channel V2 (voltage) should be
set to half-scale to allow calibration of the meter constant. The
current channel should also be no more than half scale when
the meter sees maximum load. This allows overcurrent signals
and signals with high crest factors to be accommodated. Table 9
shows the output frequency on F1 and F2 when both analog
inputs are half scale. The frequencies in Table 9 align very well
with those in Table 8 for maximum load.
Table 9. F1 and F2 Frequency with Half-Scale AC Inputs
S1
0
0
1
1
1
MAX
Values are generated using the nominal frequency of 450 kHz.
Values are generated using the nominal frequency of 450 kHz.
(A)
S0
0
1
0
1
1–4
S1
0
0
0
0
1
1
1
1
frequencies allow complete coverage of this range of
F
0.86
1.72
3.43
6.86
1–4
(Hz)
F1 and F2 (Hz)
0.076
0.153
0.244
0.367
0.489
0.733
S0
0
0
1
1
0
0
1
1
MAX
Frequency on F1 and F2—
CH1 and CH2 Half-Scale AC Input
0.051 × F
0.051 × F
0.051 × F
0.051 × F
CF Max for AC Signals (Hz)
128 × F1, F2 = 22.4
64 × F1, F2 = 11.2
64 × F1, F2 = 22.4
32 × F1, F2 = 11.2
32 × F1, F2 = 22.4
16 × F1, F2 = 11.2
16 × F1, F2 = 22.4
2048 × F1, F2 = 2.867 kHz
) with a line voltage of 220 V. In all
1
2
3
4
0.044 Hz
0.088 Hz
0.176 Hz
0.352 Hz
ADE7768
1
1