Energy Metering IC with Integrated
Oscillator and Positive Power Accumulation
ADE7768
The ADE7768 specifications surpass the accuracy requirements of the IEC62053-21 standard. The AN-679 Application
Note can be used as a basis for a description of an IEC61036
(equivalent to IEC62053-21) low cost, watt-hour meter
reference design.
FEATURES
On-chip oscillator as clock source
High accuracy, supports 50 Hz/60 Hz IEC62053-21
Less than 0.1% error over a dynamic range of 500 to 1
Supplies positive-only average real power on frequency
outputs F1 and F2
High frequency output CF calibrates and supplies
instantaneous, positive-only real power
Logic output REVP indicates potential miswiring or negative
power
Direct drive for electromechanical counters and 2-phase
stepper motors (F1 and F2)
Proprietary ADCs and DSPs provide high accuracy over
large variations in environmental conditions and time
On-chip power supply monitoring
On-chip creep protection (no-load threshold)
On-chip reference 2.45 V (20 ppm/°C typical) with
external overdrive capability
Single 5 V supply, low power (20 mW typical)
Low cost CMOS process
The only analog circuitry used in the ADE7768 is in the Σ-Δ
ADCs and reference circuit. All other signal processing, such as
multiplication and filtering, is carried out in the digital domain.
This approach provides superior stability and accuracy over
time and extreme environmental conditions.
The ADE7768 supplies positive-only average real power
information on the low frequency outputs, F1 and F2. These
outputs can be used to directly drive an electromechanical
counter or interface with an MCU. The high frequency CF logic
output, ideal for calibration purposes, provides instantaneous
positive-only, real power information.
The ADE7768 includes a power supply monitoring circuit on
the VDD supply pin. The ADE7768 remains inactive until the
supply voltage on VDD reaches approximately 4 V. If the supply
falls below 4 V, the ADE7768 also remains inactive and the F1,
F2, and CF outputs are in their nonactive modes.
GENERAL DESCRIPTION
The ADE77681 is a high accuracy, electrical energy metering IC.
It is a pin reduction version of the ADE7755, enhanced with a
precise oscillator circuit that serves as a clock source to the chip.
The ADE7768 eliminates the cost of an external crystal or
resonator, thus reducing the overall cost of a meter built with
this IC. The chip directly interfaces with the shunt resistor.
Internal phase matching circuitry ensures that the voltage and
current channels are phase matched, while the HPF in the
current channel eliminates dc offsets. An internal no-load
threshold ensures that the ADE7768 does not exhibit creep
when no load is present. When REVP is logic high, the
ADE7768 does not generate any pulse on F1, F2, and CF.
1
U.S. Patents 5,745,323; 5,760,617; 5,862,069; 5,872,469; others pending.
The ADE7768 comes in a 16-lead, narrow body SOIC package.
FUNCTIONAL BLOCK DIAGRAM
VDD
AGND
1
6
DGND
13
ADE7768
POWER
SUPPLY MONITOR
+
V2N 3
Σ-Δ
ADC
SIGNAL
PROCESSING
BLOCK
...110101...
MULTIPLIER
PHASE
CORRECTION
V1N 4
V1P 5
+
Σ-Δ
ADC
...11011001...
Φ
HPF
DIGITAL-TO-FREQUENCY
CONVERTER
INTERNAL
OSCILLATOR
2.5V
REFERENCE
LPF
4kΩ
7
REFIN/OUT
11
RCLKIN
8
10
SCF
S0
14
16
15
S1 REVP CF
9
12
F1
F2
05331-001
V2P 2
Figure 1.
Rev. A
Information furnished by Analog Devices is believed to be accurate and reliable.
However, no responsibility is assumed by Analog Devices for its use, nor for any
infringements of patents or other rights of third parties that may result from its use.
Specifications subject to change without notice. No license is granted by implication
or otherwise under any patent or patent rights of Analog Devices. Trademarks and
registered trademarks are the property of their respective owners.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700
www.analog.com
Fax: 781.461.3113
© 2005 Analog Devices, Inc. All rights reserved.
ADE7768
TABLE OF CONTENTS
Specifications..................................................................................... 3
Power Supply Monitor ............................................................... 12
Timing Characteristics ................................................................ 4
Internal Oscillator (OSC).......................................................... 14
Absolute Maximum Ratings............................................................ 5
Transfer Function....................................................................... 14
ESD Caution.................................................................................. 5
Selecting a Frequency for an Energy Meter Application ...... 15
Terminology ...................................................................................... 6
No-Load Threshold.................................................................... 16
Pin Configuration and Function Descriptions............................. 7
Negative Power Information..................................................... 16
Typical Performance Characteristics ............................................. 8
Evaluation Board and Reference Design Board ..................... 16
Functional Description .................................................................. 10
Outline Dimensions ....................................................................... 17
Theory of Operation .................................................................. 10
Ordering Guide .......................................................................... 17
Analog Inputs.............................................................................. 11
Revision History
8/05—Sp0 to Rev. A
Rev. A | Page 2 of 20
ADE7768
SPECIFICATIONS
VDD = 5 V ± 5%, AGND = DGND = 0 V, on-chip reference, RCLKIN = 6.2 kΩ, 0.5% ± 50 ppm/°C, TMIN to TMAX = −40°C to +85°C,
unless otherwise noted.
Table 1.
Parameter
ACCURACY 1 , 2
Measurement Error on Channel V1
Phase Error1 Between Channels
V1 Phase Lead 37° (PF = 0.8 Capacitive)
V1 Phase Lag 60° (PF = 0.5 Inductive)
AC Power Supply Rejection1
Output Frequency Variation (CF)
DC Power Supply Rejection1
Output Frequency Variation (CF)
ANALOG INPUTS
Channel V1 Maximum Signal Level
Channel V2 Maximum Signal Level
Input Impedance (DC)
Bandwidth (–3 dB)
ADC Offset Error1, 2
Gain Error1
OSCILLATOR FREQUENCY (OSC)
Oscillator Frequency Tolerance1
Oscillator Frequency Stability1
REFERENCE INPUT
REFIN/OUT Input Voltage Range
Input Capacitance
ON-CHIP REFERENCE
Reference Error
Temperature Coefficient
LOGIC INPUTS 3
SCF, S0, S1
Input High Voltage, VINH
Input Low Voltage, VINL
Input Current, IIN
Input Capacitance, CIN
LOGIC OUTPUTS3
F1 and F2
Output High Voltage, VOH
Output Low Voltage, VOL
CF
Output High Voltage, VOH
Output Low Voltage, VOL
Frequency Output Error1, 2 (CF)
Value
Unit
Test Conditions/Comments
0.1
% reading typ
Channel V2 with full-scale signal (±165 mV),
25°C over a dynamic range 500 to 1,
line frequency = 45 Hz to 65 Hz
±0.1
±0.1
Degrees (°) max
Degrees (°) max
0.2
% reading typ
S0 = S1 = 1, V1 = 21.2 mV rms, V2 = 116.7 mV rms @
50 Hz, ripple on VDD of 200 mV rms @ 100 Hz
±0.3
% reading typ
±30
±165
320
7
±18
mV max
mV max
kΩ min
kHz nominal
mV max
±4
% ideal typ
450
±12
±30
kHz nominal
% reading typ
ppm/°C typ
S0 = S1 = 1, V1 = 21.2 mV rms, V2 = 116.7 mV rms,
VDD = 5 V ± 250 mV
See the Analog Inputs section
V1P and V1N to AGND
V2P and V2N to AGND
OSC = 450 kHz, RCLKIN = 6.2 kΩ, 0.5% ± 50 ppm/°C
OSC = 450 kHz, RCLKIN = 6.2 kΩ, 0.5% ± 50 ppm/°C
See the Terminology and the Typical Performance
Characteristics sections
External 2.5 V reference, V1 = 21.2 mV rms,
V2 = 116.7 mV rms
RCLKIN = 6.2 kΩ, 0.5% ± 50 ppm/°C
2.65
2.25
10
V max
V min
pF max
±200
±20
mV max
ppm/°C typ
2.4
0.8
±1
10
V min
V max
μA max
pF max
VDD = 5 V ± 5%
VDD = 5 V ± 5%
Typically 10 nA, VIN = 0 V to VDD
4.5
0.5
V min
V max
ISOURCE = 10 mA, VDD = 5 V, ISINK = 10 mA, VDD = 5 V
4
0.5
±10
V min
V max
% ideal typ
ISOURCE = 5 mA, VDD = 5 V, ISINK = 5 mA, VDD = 5 V
2.45 V nominal
2.45 V nominal
2.45 V nominal
Rev. A | Page 3 of 20
External 2.5 V reference, V1 = 21.2 mV rms,
V2 = 116.7 mV rms
ADE7768
Parameter
POWER SUPPLY
VDD
IDD
Value
Unit
4.75
5.25
5
V min
V max
mA max
Test Conditions/Comments
For specified performance
5 V – 5%
5 V + 5%
Typically 4 mA
1
See the Terminology section for an explanation of specifications.
2
See the figures in the Typical Performance Characteristics section.
3
Sample tested during initial release and after any redesign or process change that may affect this parameter.
TIMING CHARACTERISTICS
VDD = 5 V ± 5%, AGND = DGND = 0 V, on-chip reference, RCLKIN = 6.2 kΩ, 0.5% ± 50 ppm/°C, TMIN to TMAX = –40°C to +85°C,
unless otherwise noted. Sample tested during initial release and after any redesign or process change that may affect this parameter.
See Figure 2.
Table 2.
Parameter
1
t1
t2
t3
t41, 2
t5
t6
2
Unit
Test Conditions/Comments
120
See Table 6
1/2 t2
90
See Table 7
2
ms
sec
sec
ms
sec
μs
F1 and F2 pulse width (logic low)
Output pulse period. See the Transfer Function section.
Time between the F1 and F2 falling edges.
CF pulse width (logic high).
CF pulse period. See the Transfer Function section.
Minimum time between the F1 and F2 pulses.
The pulse widths of F1, F2, and CF are not fixed for higher output frequencies. See the Frequency Outputs section.
The CF pulse is always 35 μs in high frequency mode. See the Frequency Outputs section and Table 7.
t1
F1
t6
t2
F2
t3
t4
t5
05331-002
1
Specifications
CF
Figure 2. Timing Diagram for Frequency Outputs
Rev. A | Page 4 of 20
ADE7768
ABSOLUTE MAXIMUM RATINGS
TA = 25°C, unless otherwise noted.
Table 3.
Parameter
VDD to AGND
VDD to DGND
Analog Input Voltage to AGND,
V1P, V1N, V2P, and V2N
Reference Input Voltage to AGND
Digital Input Voltage to DGND
Digital Output Voltage to DGND
Operating Temperature Range
Storage Temperature Range
Junction Temperature
16-Lead Plastic SOIC, Power Dissipation
θJA Thermal Impedance 1
Package Temperature Soldering
1
Value
−0.3 V to +7 V
−0.3 V to +7 V
−6 V to +6 V
−0.3 V to VDD + 0.3 V
−0.3 V to VDD + 0.3 V
−0.3 V to VDD + 0.3 V
−40°C to +85°C
−65°C to +150°C
150°C
350 mW
124.9°C/W
See J-STD-20
Stresses above those listed under Absolute Maximum Ratings
may cause permanent damage to the device. This is a stress
rating only and functional operation of the device at these or
any other conditions above those indicated in the operational
section of this specification is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect
device reliability.
JEDEC 1S standard (2-layer) board data.
ESD CAUTION
ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily accumulate on
the human body and test equipment and can discharge without detection. Although this product features
proprietary ESD protection circuitry, permanent damage may occur on devices subjected to high energy
electrostatic discharges. Therefore, proper ESD precautions are recommended to avoid performance degradation or loss of functionality.
Rev. A | Page 5 of 20
ADE7768
TERMINOLOGY
Measurement Error
The error associated with the energy measurement made by the
ADE7768 is defined by the following formula:
% Error =
Energy Registered by ADE7768 − True Energy
True Energy
× 100%
Phase Error Between Channels
The high-pass filter (HPF) in the current channel (Channel V1)
has a phase-lead response. To offset this phase response and
equalize the phase response between channels, a phasecorrection network is also placed in Channel V1. The phasecorrection network matches the phase to within 0.1° over a
range of 45 Hz to 65 Hz, and 0.2° over a range 40 Hz to 1 kHz
(see Figure 24 and Figure 25).
Power Supply Rejection (PSR)
This quantifies the ADE7768 measurement error as a
percentage of reading when the power supplies are varied.
For the ac PSR measurement, a reading at nominal supplies
(5 V) is taken. A 200 mV rms/100 Hz signal is then introduced
onto the supplies and a second reading is obtained under the
same input signal levels. Any error introduced is expressed as a
percentage of reading—see the Measurement Error definition.
For the dc PSR measurement, a reading at nominal supplies
(5 V) is taken. The supplies are then varied 5% and a second
reading is obtained with the same input signal levels. Any error
introduced is again expressed as a percentage of the reading.
ADC Offset Error
This refers to the small dc signal (offset) associated with the
analog inputs to the ADCs. However, the HPF in Channel V1
eliminates the offset in the circuitry. Therefore, the power
calculation is not affected by this offset.
Frequency Output Error (CF)
The frequency output error of the ADE7768 is defined as the
difference between the measured output frequency (minus the
offset) and the ideal output frequency. The difference is
expressed as a percentage of the ideal frequency. The ideal
frequency is obtained from the ADE7768 transfer function.
Gain Error
The gain error of the ADE7768 is defined as the difference
between the measured output of the ADCs (minus the offset)
and the ideal output of the ADCs. The difference is expressed
as a percentage of the ideal of the ADCs.
Oscillator Frequency Tolerance
The oscillator frequency tolerance of the ADE7768 is defined as
the part-to-part frequency variation in terms of percentage at
room temperature (25°C). It is measured by taking the difference between the measured oscillator frequency and the
nominal frequency defined in the Specifications section.
Oscillator Frequency Stability
Oscillator frequency stability is defined as frequency variation
in terms of the parts-per-million drift over the operating
temperature range. In a metering application, the temperature
range is −40°C to +85°C. Oscillator frequency stability is
measured by taking the difference between the measured
oscillator frequency at −40°C and +85°C and the measured
oscillator frequency at +25°C.
Rev. A | Page 6 of 20
ADE7768
PIN CONFIGURATION AND FUNCTION DESCRIPTIONS
VDD 1
16 F1
V2P 2
15 F2
V2N 3
ADE7768
14 CF
V1N 4
13 DGND
TOP VIEW
V1P 5 (Not to Scale) 12 REVP
SCF 8
11 RCLKIN
10 S0
9
S1
05331-003
AGND 6
REFIN/OUT 7
Figure 3. Pin Configuration
Table 4. Pin Function Descriptions
Pin No.
Mnemonic
Description
1
VDD
2, 3
V2P, V2N
4, 5
V1N, V1P
6
AGND
7
REFIN/OUT
8
SCF
9, 10
S1, S0
Power Supply. This pin provides the supply voltage for the circuitry in the ADE7768. The supply voltage
should be maintained at 5 V ± 5% for specified operation. This pin should be decoupled with a 10 μF
capacitor in parallel with a 100 nF ceramic capacitor.
Analog Inputs for Channel V2 (Voltage Channel). These inputs provide a fully differential input pair. The
maximum differential input voltage is ±165 mV for specified operation. Both inputs have internal ESD
protection circuitry; an overvoltage of ±6 V can be sustained on these inputs without risk of permanent
damage.
Analog Inputs for Channel V1 (Current Channel). These inputs are fully differential voltage inputs with a
maximum signal level of ±30 mV with respect to the V1N pin for specified operation. Both inputs have
internal ESD protection circuitry and, in addition, an overvoltage of ±6 V can be sustained on these inputs
without risk of permanent damage.
This pin provides the ground reference for the analog circuitry in the ADE7768, that is, the ADCs and
reference. This pin should be tied to the analog ground plane of the PCB. The analog ground plane is the
ground reference for all analog circuitry, such as antialiasing filters, current and voltage sensors, and so forth.
For accurate noise suppression, the analog ground plane should be connected to the digital ground plane at
only one point. A star ground configuration helps to keep noisy digital currents away from the analog
circuits.
This pin provides access to the on-chip voltage reference. The on-chip reference has a nominal value of 2.45 V
and a typical temperature coefficient of 20 ppm/°C. An external reference source may also be connected at
this pin. In either case, this pin should be decoupled to AGND with a 1 μF tantalum capacitor and a 100 nF
ceramic capacitor. The internal reference cannot be used to drive an external load.
Select Calibration Frequency. This logic input is used to select the frequency on the calibration output CF.
See Table 7.
These logic inputs are used to select one of four possible frequencies for the digital-to-frequency conversion.
With this logic input, designers have greater flexibility when designing an energy meter. See the Selecting a
Frequency for an Energy Meter Application section.
11
RCLKIN
To enable the internal oscillator as a clock source to the chip, a precise low temperature drift resistor at a
nominal value of 6.2 kΩ must be connected from this pin to DGND.
12
REVP
13
DGND
14
CF
15, 16
F2, F1
This logic output goes high when negative power is detected, that is, when the phase angle between the
voltage and current signals is greater than 90°. This output is not latched and is reset when positive power is
once again detected. The output goes high or low at the same time that a pulse is issued on CF.
This pin provides the ground reference for the digital circuitry in the ADE7768, that is, the multiplier, filters,
and digital-to-frequency converter. This pin should be tied to the digital ground plane of the PCB. The digital
ground plane is the ground reference for all digital circuitry, such as counters (mechanical and digital), MCUs,
and indicator LEDs. For accurate noise suppression, the analog ground plane should be connected to the
digital ground plane at one point only—a star ground.
Calibration Frequency Logic Output. The CF logic output provides instantaneous, positive-only real power
information. This output is intended for calibration purposes. See the SCF pin description.
Low Frequency Logic Outputs. F1 and F2 supply average positive-only real power information. The logic
outputs can be used to directly drive electromechanical counters and 2-phase stepper motors. See the
Transfer Function section.
Rev. A | Page 7 of 20
ADE7768
TYPICAL PERFORMANCE CHARACTERISTICS
VDD
+
100nF
10μF
1
VDD
602kΩ
220V
150nF
200Ω
200Ω
40A TO
40mA
3
U1
F2 15
ADE7768
CF 14
2
3
K8
820Ω
REVP 12
200Ω
V1P
4
V1N
150nF
350μΩ
4
PS2501-1
150nF
+
1
V2N
5
K7
U3
F1 16
V2P
2
6.2kΩ
RCLKIN 11
VDD
200Ω
10kΩ
150nF
S0 10
S1 9
REFIN/OUT
7
+
SCF 8
100nF
1μF
10nF
AGND DGND
10nF
10nF
13
05331-004
6
Figure 4. Test Circuit for Performance Curves
1.0
1.0
PF = 1
ON-CHIP REFERENCE
0.8
0.6
ERROR (% of Reading)
0.6
–40°C
0.4
0.2
0
–0.2
+85°C
+25°C
–0.4
0.2
+85°C
0
–0.2
+25°C
–0.4
–40°C
–0.8
–1.0
0.1
1
10
–0.8
–1.0
0.1
100
CURRENT CHANNEL (% of Full Scale)
1
10
100
CURRENT CHANNEL (% of Full Scale)
Figure 5. Error as a % of Reading over Temperature
with On-Chip Reference (PF = 1)
Figure 7. Error as a % of Reading over Temperature
with External Reference (PF = 1)
1.0
1.0
PF = 0.5 IND
ON-CHIP REFERENCE
0.8
0.6
0.6
ERROR (% of Reading)
–40°C, PF = 0.5 IND
0.4
0.2
+25°C, PF = 1
0
–0.2
+25°C, PF = 0.5 IND
–0.4
PF = 0.5 IND
EXTERNAL REFERENCE
0.8
+85°C, PF = 0.5 IND
–0.6
0.4
0.2
+25°C, PF = 1
+85°C, PF = 0.5 IND
0
–0.2
–0.4
+25°C, PF = 0.5 IND
–0.6
–0.8
–1.0
0.1
–40°C, PF = 0.5 IND
05331-020
ERROR (% of Reading)
05331-021
–0.6
05331-019
–0.6
0.4
1
10
–0.8
–1.0
0.1
100
CURRENT CHANNEL (% of Full Scale)
1
10
CURRENT CHANNEL (% of Full Scale)
Figure 6. Error as a % of Reading over Temperature
with On-Chip Reference (PF = 0.5 IND)
Figure 8. Error as a % of Reading over Temperature
with External Reference (PF = 0.5 IND)
Rev. A | Page 8 of 20
05331-022
ERROR (% of Reading)
PF = 1
EXTERNAL REFERENCE
0.8
100
ADE7768
40
0.5
0.4
30
0.2
PF = 0.5 IND
PF = 1
0.1
FREQUENCY
ERROR (% of Reading)
0.3
DISTRIBUTION CHARACTERISTICS
MEAN = 2.247828
EXTERNAL REFERENCE
SDs = 1.367176
TEMPERATURE = 25°C
MIN = –2.09932
MAX = +5.28288
NO. OF POINTS = 100
0
–0.1
–0.2
20
PF = 0.5 CAP
10
–0.4
–0.5
45
50
55
60
05331-025
05331-018
–0.3
0
–5 –4 –3 –2 –1
65
PF = 1
ON-CHIP REFERENCE
40
0.6
0.4
3
4
5
6
7
8
9
DISTRIBUTION CHARACTERISTICS
MEAN = –1.563484
SDs = 2.040699
EXTERNAL REFERENCE
MIN = –6.82969
TEMPERATURE = 25°C
MAX = +2.6119
NO. OF POINTS = 100
5.25V
FREQUENCY
0.2
5V
0
4.75V
–0.2
30
20
–0.4
10
05331-023
–0.6
–0.8
–1.0
0.1
1
10
05331-026
ERROR (% of Reading)
2
50
1.0
0
–12 –10 –8
100
–6
–2
0
2
4
6
8
10
12
Figure 13. Channel V2 Offset Distribution
Figure 10. PSR with On-Chip Reference, PF = 1
1000
1.0
0.8
–4
CHANNEL V2 OFFSET (mV)
CURRENT CHANNEL (% of Full Scale)
PF = 1
EXTERNAL REFERENCE
800
0.6
0.4
DISTRIBUTION CHARACTERISTICS
MEAN = 0%
EXTERNAL REFERENCE
SDs = 1.55%
TEMPERATURE = 25°C
MIN = –11.79%
MAX = +6.08%
NO. OF POINTS = 3387
FREQUENCY
5.25V
0.2
5V
0
–0.2
4.75V
600
400
–0.4
–0.8
–1.0
0.1
1
10
05331-027
200
–0.6
05331-024
ERROR (% of Reading)
1
Figure 12. Channel V1 Offset Distribution
Figure 9. Error as a % of Reading over Input Frequency
0.8
0
CHANNEL V1 OFFSET (mV)
FREQUENCY (Hz)
0
100
–10
–8
–6
–4
–2
0
2
4
6
8
DEVIATION FROM MEAN (%)
CURRENT CHANNEL (% of Full Scale)
Figure 11. PSR with External Reference, PF = 1
Figure 14. Part-to-Part CF Deviation from Mean
Rev. A | Page 9 of 20
10
12
ADE7768
The real power calculation is derived from the instantaneous
power signal. The instantaneous power signal is generated by
a direct multiplication of the current and voltage signals. To
extract the real power component (the dc component), the
instantaneous power signal is low-pass filtered. Figure 15
illustrates the instantaneous real power signal and shows how
the real power information can be extracted by low-pass
filtering the instantaneous power signal. In the ADE7768,
this signal is compared to 0 and only positive real power is
accumulated for F1, F2, and CF pulse outputs. This scheme
correctly calculates real power for sinusoidal current and
voltage waveforms at all power factors. All signal processing
is carried out in the digital domain for superior stability over
temperature and time.
0Wh
0W
Power Factor Considerations
The method used to extract the real power information from
the instantaneous power signal (that is, by low-pass filtering) is
still valid even when the voltage and current signals are not in
phase. Figure 17 displays the unity power factor condition and a
displacement power factor (DPF) = 0.5 (a current signal lagging
the voltage by 60°). Assuming that the voltage and current
waveforms are sinusoidal, the real power component of the
instantaneous power signal (that is, the dc term) is given by
⎛V × I ⎞
⎜
⎟ × cos (60°)
⎝ 2 ⎠
≥0
MULTIPLIER
DIGITAL-TOFREQUENCY
LPF
ADC
CH2
INSTANTANEOUS
POWER SIGNAL – p(t)
This is the correct real power calculation.
F2
HPF
(1)
INSTANTANEOUS REAL
POWER SIGNAL
INSTANTANEOUS
POWER SIGNAL
POWER
CF
INSTANTANEOUS REAL
POWER SIGNAL
V×I
2
TIME
TIME
05331-005
0V
TIME
CURRENT
VOLTAGE
POWER INSTANTANEOUS
POWER SIGNAL
Figure 15. Signal Processing Block Diagram
The low frequency outputs (F1 and F2) are generated by
accumulating positive-only real power information. This low
frequency inherently means a long accumulation time between
output pulses. Consequently, the resulting output frequency is
proportional to the average positive-only real power. This
average positive-only real power information is then accumulated (by a counter) to generate real energy information (see
Figure 16). Conversely, due to its high output frequency and
shorter integration time, the CF output frequency is proportional to the instantaneous positive-only real power. This is
useful for system calibration, which can be done faster under
steady load conditions.
INSTANTANEOUS REAL
POWER SIGNAL
V×I
COS (60°)
2
Rev. A | Page 10 of 20
TIME
0V
VOLTAGE
CURRENT
60°
Figure 17. DC Component of Instantaneous Power Signal Conveys
Real Power Information, PF < 1
05331-006
ADC
INSTANTANEOUS
POWER
Figure 16. Positive-Only Energy Accumulation
DIGITAL-TOFREQUENCY
F1
CH1
ACTIVE ENERGY
05331-028
The two ADCs in the ADE7768 digitize the voltage signals from
the current and voltage sensors. These ADCs are 16-bit Σ-Δs
with an oversampling rate of 450 kHz. This analog input
structure greatly simplifies sensor interfacing by providing a
wide dynamic range for direct connection to the sensor and
by simplifying the antialiasing filter design. A high-pass filter
in the current channel removes any dc component from the
current signal. This eliminates any inaccuracies in the real
power calculation due to offsets in the voltage or current
signals.
MAGNITUDE
THEORY OF OPERATION
MAGNITUDE
FUNCTIONAL DESCRIPTION
ADE7768
Nonsinusoidal Voltage and Current
ANALOG INPUTS
The real power calculation method also holds true for nonsinusoidal current and voltage waveforms. All voltage and
current waveforms in practical applications have some
harmonic content. Using the Fourier transform, instantaneous
voltage and current waveforms can be expressed in terms of
their harmonic content.
Channel V1 (Current Channel)
v(t ) = V0 + 2 × ∑ Vh × sin(hωt + αh )
∞
(2)
The voltage output from the current sensor is connected to the
ADE7768 here. Channel V1 is a fully differential voltage input.
V1P is the positive input with respect to V1N.
The maximum peak differential signal on Channel V1 should
be less than ±30 mV (21 mV rms for a pure sinusoidal signal)
for specified operation.
h≠0
V1
+30mV
where:
v(t) is the instantaneous voltage.
V0 is the average value.
Vh is the rms value of voltage harmonic h.
α h is the phase angle of the voltage harmonic.
V1P
DIFFERENTIAL INPUT
±30mV MAX PEAK
V1
VCM
COMMON-MODE
±6.25mV MAX
V1N
05331-007
VCM
AGND
–30mV
∞
i (t ) = I O + 2 × ∑ I h × sin(hω t + βh )
(3)
h≠ o
Figure 18 shows the maximum signal levels on V1P and V1N.
The maximum differential voltage is ±30 mV. The differential
voltage signal on the inputs must be referenced to a common
mode, such as AGND. The maximum common-mode signal is
±6.25 mV.
where:
i(t) is the instantaneous current.
I0 is the dc component.
Ih is the rms value of current harmonic h.
βh is the phase angle of the current harmonic.
Using Equations 2 and 3, the real power (P) can be expressed in
terms of its fundamental real power (P1) and harmonic real
power (PH) as P = P1 + PH
where:
P1 = V1 × I 1 cos φ 1
Figure 18. Maximum Signal Levels, Channel V1
(4)
Channel V2 (Voltage Channel)
The output of the line voltage sensor is connected to the device
at this analog input. Channel V2 is a fully differential voltage
input with a maximum peak differential signal of ±165 mV.
Figure 19 shows the maximum signal levels that can be
connected to the ADE7768 Channel V2.
V2
φ1 = α 1 − β 1
+165mV
V2P
DIFFERENTIAL INPUT
±165mV MAX PEAK
∞
PH = ∑Vh × I h cos φh
h ≠1
(5)
VCM
COMMON-MODE
±25mV MAX
φh = α h − β h
–165mV
In Equation 5, a harmonic real power component is generated
for every harmonic, provided that harmonic is present in both
the voltage and current waveforms. The power factor calculation has previously been shown to be accurate in a pure
sinusoid. Therefore, the harmonic real power must also
correctly account for the power factor, because it is made up
of a series of pure sinusoids.
Note that the input bandwidth of the analog inputs is 7 kHz at
the nominal internal oscillator frequency of 450 kHz.
V2
V2N
VCM
AGND
05331-008
and
Figure 19. Maximum Signal Levels, Channel V2
Channel V2 is usually driven from a common-mode voltage,
that is, the differential voltage signal on the input is referenced
to a common mode (usually AGND). The analog inputs of the
ADE7768 can be driven with common-mode voltages of up to
25 mV with respect to AGND. However, best results are
achieved using a common mode equal to AGND.
Rev. A | Page 11 of 20
ADE7768
Typical Connection Diagrams
HPF and Offset Effects
Figure 20 shows a typical connection diagram for Channel V1.
A shunt is the current sensor selected for this example because
of its low cost compared to other current sensors, such as the
current transformer (CT). This IC is ideal for low current
meters.
Figure 23 shows the effect of offsets on the real power calculation. As can be seen, offsets on Channel V1 and Channel V2
contribute a dc component after multiplication. Because this dc
component is extracted by the LPF and used to generate the real
power information, the offsets contribute a constant error to the
real power calculation. This problem is easily avoided by the
built-in HPF in Channel V1. By removing the offsets from at
least one channel, no error component can be generated at dc
by the multiplication. Error terms at the line frequency (ω) are
removed by the LPF and the digital-to-frequency conversion
(see the Digital-to-Frequency Conversion section).
RF
V1P
CF
±30mV
SHUNT
V1N
CF
05331-009
RF
AGND
PHASE
NEUTRAL
Equation 6 shows how the power calculation is affected by the
dc offsets in the current and voltage channels.
Figure 20. Typical Connection for Channel V1
Figure 21 shows a typical connection for Channel V2. Typically,
the ADE7768 is biased around the phase wire, and a resistor
divider is used to provide a voltage signal that is proportional to
the line voltage. Adjusting the ratio of RA, RB, and RF is also a
convenient way of carrying out a gain calibration on a meter.
{V cos (ωt ) + VOS } × {I cos (ωt ) + I OS }
=
B
RB
RF
CF
±165mV V2N
RF
NEUTRAL PHASE
+
V2P
V ×I
+ VOS × I OS + VOS × I cos (ωt ) + I OS × V cos (ωt )
2
V×I
2
× cos (2ωt )
DC COMPONENT (INCLUDING ERROR TERM)
IS EXTRACTED BY THE LPF FOR REAL
POWER CALCULATION
CF
05331-010
RA *
*RA >> RB + RF
(6)
VOS × IOS
V×I
2
Figure 21. Typical Connections for Channel V2
IOS × V
POWER SUPPLY MONITOR
In Figure 22, the trigger level is nominally set at 4 V. The tolerance on this trigger level is within ±5%. The power supply and
decoupling for the part should be such that the ripple at VDD
does not exceed 5 V ± 5%, as specified for normal operation.
05331-012
VOS × I
The ADE7768 contains an on-chip power supply monitor.
The power supply (VDD) is continuously monitored by the
ADE7768. If the supply is less than 4 V, the ADE7768 becomes
inactive. This is useful to ensure proper device operation at
power-up and power-down. The power supply monitor has
built-in hysteresis and filtering, which provide a high degree
of immunity to false triggering from noisy supplies.
0
FREQUENCY (RAD/s)
Figure 23. Effect of Channel Offset on the Real Power Calculation
The HPF in Channel V1 has an associated phase response that
is compensated for on chip. Figure 24 and Figure 25 show the
phase error between channels with the compensation network
activated. The ADE7768 is phase compensated up to 1 kHz as
shown. This ensures correct active harmonic power calculation
even at low power factors.
0.30
0.25
0.20
VDD
PHASE (Degrees)
5V
4V
0V
0.15
0.10
0.05
0
TIME
INACTIVE
ACTIVE
INACTIVE
–0.10
0
05331-011
INTERNAL
ACTIVATION
05331-013
–0.05
100
200
300
400
500
600
700
800
900 1000
FREQUENCY (Hz)
Figure 24. Phase Error Between Channels (0 Hz to 1 kHz)
Figure 22. On-Chip Power Supply Monitor
Rev. A | Page 12 of 20
ADE7768
DIGITAL-TOFREQUENCY
F1
V
F2
0.15
MULTIPLIER
0.10
I
≥0
LPF
TIME
DIGITAL-TOFREQUENCY
CF
LPF TO EXTRACT
REAL POWER
(DC TERM)
0.05
TIME
V×I
2
0
COS (2ω)
ATTENUATED BY LPF
05331-014
–0.05
–0.10
40
45
50
55
60
65
70
Figure 25. Phase Error Between Channels (40 Hz to 70 Hz)
Digital-to-Frequency Conversion
Figure 26. Positive-Only, Real Power-to-Frequency Conversion
As previously described, the digital output of the low-pass filter
after multiplication contains the positive-only real power
information. However, because this LPF is not an ideal brick
wall filter implementation, the output signal also contains
attenuated components at the line frequency and its harmonics,
that is, cos(hωt) where h = 1, 2, 3, ... and so on.
The magnitude response of the filter is given by
1
1+
ω
2ω
FREQUENCY (RAD/s)
INSTANTANEOUS REAL POWER SIGNAL
(FREQUENCY DOMAIN)
0
FREQUENCY (Hz)
H(f ) =
CF
05331-015
PHASE (Degrees)
0.20
FREQUENCY
0.25
FREQUENCY
F1
0.30
(7)
f2
4.452
For a line frequency of 50 Hz, this gives an attenuation of
the 2ω (100 Hz) component of approximately 22 dB. The
dominating harmonic is twice the line frequency (2ω) due to
the instantaneous power calculation.
Figure 26 shows the instantaneous positive-only real power
signal at the output of the LPF that still contains a significant
amount of instantaneous power information, that is, cos(2ωt).
This signal is then passed to the digital-to-frequency converter
where it is compared to 0 and only positive real power is integrated (accumulated) over time to produce an output frequency.
The accumulation of the signal suppresses or averages out any
non-dc components in the instantaneous positive-only real
power signal. The average value of a sinusoidal signal is 0. Thus,
the frequency generated by the ADE7768 is proportional to the
average positive-only real power. Figure 26 shows the digital-tofrequency conversion for steady load conditions, that is, the
constant voltage and current.
In Figure 26, the frequency output CF varies over time, even
under steady load conditions. This frequency variation is
primarily due to the cos(2ωt) component in the instantaneous
positive-only real power signal. The output frequency on CF
can be up to 2048 times higher than the frequency on F1 and
F2. This higher output frequency is generated by accumulating
the instantaneous positive-only real power signal over a much
shorter time while converting it to a frequency. This shorter
accumulation period means less averaging of the cos(2ωt)
component. Consequently, some of this instantaneous power
signal passes through the digital-to-frequency conversion. This
is not a problem in the application. Where CF is used for
calibration purposes, the frequency should be averaged by the
frequency counter, which removes any ripple. If CF is used to
measure energy, such as in a microprocessor-based application,
the CF output should also be averaged to calculate power.
Because the F1 and F2 outputs operate at a much lower
frequency, much more averaging of the instantaneous positiveonly real power signal is carried out. The result is a greatly
attenuated sinusoidal content and a virtually ripple-free
frequency output.
Connecting to a Microcontroller for Energy
Measurement
The easiest way to interface the ADE7768 to a microcontroller
is to use the CF high frequency output with the output
frequency scaling set to 2048 × F1, F2. This is done by setting
SCF = 0 and S0 = S1 = 1 (see Table 7). With full-scale ac
signals on the analog inputs, the output frequency on CF is
approximately 2.867 kHz. Figure 27 illustrates one scheme that
could be used to digitize the output frequency and carry out the
necessary averaging mentioned in the previous section.
Rev. A | Page 13 of 20
ADE7768
CF
temperature drift to ensure stability and linearity of the chip.
The oscillator frequency is inversely proportional to the
RCLKIN, as shown in Figure 28. Although the internal
oscillator operates when used with RCLKIN values between
5.5 kΩ and 20 kΩ, choosing a value within the range of the
nominal value, as shown in Figure 28, is recommended.
FREQUENCY
RIPPLE
AVERAGE
FREQUENCY
±10%
490
TIME
MCU
480
COUNTER
470
05331-016
TIMER
FREQUENCY (kHz)
CF
Figure 27. Interfacing the ADE7768 to an MCU
As shown in Figure 27, the frequency output CF is connected
to an MCU counter or port. This counts the number of pulses
in a given integration time, which is determined by an MCU
internal timer. The average power proportional to the average
frequency is given by
Counter
Average Frequency = Average Power =
Time
460
450
440
430
420
05331-017
ADE7768
410
400
5.8
5.9
6.0
6.1
6.2
6.3
6.4
6.5
6.6
6.7
RESISTANCE (kΩ)
Figure 28. Effect of RCLKIN on Internal Oscillator Frequency (OSC)
(8)
The energy consumed during an integration period is given by
Counter
Energy = Average Power × Time =
× Time = Counter (9)
Time
For the purpose of calibration, this integration time could be
10 seconds to 20 seconds, to accumulate enough pulses to
ensure correct averaging of the frequency. In normal operation,
the integration time could be reduced to 1 second or 2 seconds,
depending, for example, on the required update rate of a
display. With shorter integration times on the MCU, the
amount of energy in each update may still have some small
amount of ripple, even under steady load conditions. However,
over a minute or more the measured energy has no ripple.
Power Measurement Considerations
Calculating and displaying power information always has some
associated ripple, which depends on the integration period used
in the MCU to determine average power and also on the load.
For example, at light loads, the output frequency may be 10 Hz.
With an integration period of 2 seconds, only about 20 pulses
are counted. The possibility of missing one pulse always exists,
because the ADE7768 output frequency is running asynchronously to the MCU timer. This results in a 1-in-20 or 5% error
in the power measurement. When REVP is logic high, the
ADE7768 does not generate any pulse on F1, F2, and CF.
TRANSFER FUNCTION
Frequency Outputs F1 and F2
The ADE7768 calculates the product of two voltage signals
(on Channel V1 and Channel V2) and then low-pass filters this
product to extract positive-only real power information. This
positive-only real power information is then converted to a
frequency. The frequency information is output on F1 and F2
in the form of active low pulses. The pulse rate at these outputs
is relatively low—for example, 0.175 Hz maximum for ac signals
with S0 = S1 = 0 (see Table 6). This means that the frequency at
these outputs is generated from positive-only real power
information accumulated over a relatively long period of time.
The result is an output frequency that is proportional to the
average positive-only real power. The averaging of the positiveonly real power signal is implicit to the digital-to-frequency
conversion. The output frequency or pulse rate is related to the
input voltage signals by the following equation:
Freq =
494.75 × V1rms × V2rms × F1− 4
VREF 2
(10)
where:
Freq is the output frequency on F1 and F2 (Hz).
V1rms is the differential rms voltage signal on Channel V1 (V).
V2rms is the differential rms voltage signal on Channel V2 (V).
VREF is the reference voltage (2.45 V ± 200 mV) (V).
F1–4 are one of four possible frequencies selected by using the
S0 and S1 logic inputs (see Table 5).
INTERNAL OSCILLATOR (OSC)
The nominal internal oscillator frequency is 450 kHz when
used with RCLKIN, with a nominal value of 6.2 kΩ. The
frequency outputs are directly proportional to the oscillator
frequency, thus RCLKIN must have low tolerance and low
Rev. A | Page 14 of 20
ADE7768
Table 5. F1–4 Frequency Selection
S1
0
0
1
1
1
2
S0
0
1
0
1
OSC Relation
OSC/219
OSC/218
OSC/217
OSC/216
1
Table 7. Maximum Output Frequency on CF
F1–4 at Nominal OSC (Hz)
0.86
1.72
3.43
6.86
2
F1–4 is a binary fraction of the internal oscillator frequency.
Values are generated using the nominal frequency of 450 kHz.
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:
1
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.
494.75 × 0.03 × 0.165 × F1
2 × 2 × 2.45 2
= 0.204 × F1 = 0.175
(11)
1
S0
0
1
0
1
OSC Relation
0.204 × F1
0.204 × F2
0.204 × F3
0.204 × F4
S0
0
0
1
1
0
0
1
1
CF Max for AC Signals (Hz) 1
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
Values are generated using the nominal frequency of 450 kHz.
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 (IMAX) with a line voltage of 220 V. In all
cases, the meter constant is 100 imp/kWh.
Table 8. F1 and F2 Frequency at 100 imp/kWh
Table 6. Maximum Output Frequency on F1 and F2
S1
0
0
1
1
S1
0
0
0
0
1
1
1
1
SELECTING A FREQUENCY FOR AN ENERGY
METER APPLICATION
F1–4 = OSC/219 Hz, S0 = S1 = 0
V1rms = 0.03/√2 V
V2rms = 0.165/√2 V
VREF = 2.45 V (nominal reference value)
Freq =
SCF
1
0
1
0
1
0
1
0
1
Max Frequency or AC Inputs (Hz)
0.175
0.35
0.70
1.40
Values are generated using the nominal frequency of 450 kHz.
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 F1–4
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).
IMAX (A)
12.5
25.0
40.0
60.0
80.0
120.0
F1 and F2 (Hz)
0.076
0.153
0.244
0.367
0.489
0.733
The F1–4 frequencies allow complete coverage of this range of
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
S0
F1–4 (Hz)
Frequency on F1 and F2—
CH1 and CH2 Half-Scale AC Input1
0
0
1
1
0
1
0
1
0.86
1.72
3.43
6.86
0.051 × F1
0.051 × F2
0.051 × F3
0.051 × F4
1
0.044 Hz
0.088 Hz
0.176 Hz
0.352 Hz
Values are generated using the nominal frequency of 450 kHz.
Rev. A | Page 15 of 20
ADE7768
When selecting a suitable F1–4 frequency for a meter design, the
frequency output at IMAX (maximum load) with a meter constant
of 100 imp/kWh should be compared with Column 4 of
Table 9. The closest frequency in Table 9 determines the best
choice of frequency (F1–4). For example, if a meter with a maximum current of 25 A is being designed, the output frequency
on F1 and F2 with a meter constant of 100 imp/kWh is 0.153 Hz
at 25 A and 220 V (from Table 8). In Table 9, the closest frequency to 0.153 Hz in Column 4 is 0.176 Hz. Therefore, as
shown in Table 5, F3 (3.43 Hz) is selected for this design.
For example, for an energy meter with a meter constant of
100 imp/kWh on F1, F2 using F3 (3.43 Hz), the minimum
output frequency at F1 or F2 would be 0.00244% of 3.43 Hz or
8.38 × 10–5 Hz. This would be 2.68 × 10–3 Hz at CF (32 × F1 Hz)
when SCF = S0 = 1, S1 = 0. In this example, the no-load
threshold would be equivalent to 3 W of load or a start-up
current of 13.72 mA at 220 V. Compare this value to the
IEC62053-21 specification which states that the meter must
start up with a load equal to or less than 0.4% Ib. For a 5 A (Ib)
meter, 0.4% of Ib is equivalent to 20 mA.
Frequency Outputs
NEGATIVE POWER INFORMATION
Figure 2 shows a timing diagram for the various frequency
outputs. The F1 and F2 outputs are the low frequency outputs
that can be used to directly drive a stepper motor or electromechanical impulse counter. The F1 and F2 outputs provide
two alternating low frequency pulses. The F1 and F2 pulse
widths (t1) are set such that if they fall below 240 ms (0.24 Hz),
they are set to half of their period. The maximum output
frequencies for F1 and F2 are shown in Table 6.
The ADE7768 detects when the current and voltage channels
have a phase shift greater than 90°. This mechanism can detect
an incorrect meter connection or the generation of negative
power. The REVP pin output goes active high when negative
power is detected and active low if positive power is detected.
The REVP pin output changes state as a pulse is issued on CF.
The high frequency CF output is intended for communications
and calibration purposes. CF produces a 90-ms-wide active
high pulse (t4) at a frequency proportional to active power. The
CF output frequencies are given in Table 7. As with F1 and F2,
if the period of CF (t5) falls below 180 ms, the CF pulse width is
set to half the period. For example, if the CF frequency is 20 Hz,
the CF pulse width is 25 ms.
When high frequency mode is selected (SCF = 0, S1 = S0 = 1),
the CF pulse width is fixed at 35 μs. Therefore, t4 is always 35 μs,
regardless of output frequency on CF.
EVALUATION BOARD AND REFERENCE DESIGN
BOARD
An evaluation board can be used to verify the functionality and
the performance of the ADE7768. Download documentation
for the board from http://www.analog.com/ADE7768.
In addition, the reference design board ADE7768ARN-REF
and Application Note AN-679 can be used in the design
of a low cost watt-hour meter that surpasses IEC62053-21
accuracy specifications. Download the application note from
http://www.analog.com/ADE7768.
NO-LOAD THRESHOLD
The ADE7768 includes a no-load threshold and start-up
current feature that eliminates any creep effects in the meter.
The ADE7768 is designed to issue a minimum output
frequency. Any load generating a frequency lower than this
minimum frequency does not cause a pulse to be issued on F1,
F2, or CF. The minimum output frequency is given as 0.00244%
for each of the F1–4 frequency selections (see Table 5).
Rev. A | Page 16 of 20
ADE7768
OUTLINE DIMENSIONS
10.00 (0.3937)
9.80 (0.3858)
4.00 (0.1575)
3.80 (0.1496)
16
9
1
8
1.27 (0.0500)
BSC
6.20 (0.2441)
5.80 (0.2283)
1.75 (0.0689)
1.35 (0.0531)
0.25 (0.0098)
0.10 (0.0039)
COPLANARITY
0.10
0.50 (0.0197)
× 45°
0.25 (0.0098)
8°
0.51 (0.0201) SEATING
0.25 (0.0098) 0° 1.27 (0.0500)
PLANE
0.31 (0.0122)
0.40 (0.0157)
0.17 (0.0067)
COMPLIANT TO JEDEC STANDARDS MS-012-AC
CONTROLLING DIMENSIONS ARE IN MILLIMETERS; INCH DIMENSIONS
(IN PARENTHESES) ARE ROUNDED-OFF MILLIMETER EQUIVALENTS FOR
REFERENCE ONLY AND ARE NOT APPROPRIATE FOR USE IN DESIGN
Figure 29. 16-Lead Standard Small Outline Package [SOIC_N]
Narrow Body (R-16)
Dimensions shown in millimeters and (inches)
ORDERING GUIDE
Model
ADE7768AR
ADE7768AR-RL
ADE7768ARZ 1
ADE7768ARZ-RL1
ADE7768AR-REF
EVAL-ADE7768EB
1
Temperature Range
−40°C to +85°C
−40°C to +85°C
−40°C to +85°C
−40°C to +85°C
Package Description
16-Lead Standard Small Outline Package [SOIC_N]
16-Lead Standard Small Outline Package [SOIC_N] REEL
16-Lead Standard Small Outline Package [SOIC_N]
16-Lead Standard Small Outline Package [SOIC_N] REEL
Reference Board
Evaluation Board
Z = Pb-free part.
Rev. A | Page 17 of 20
Package Option
R-16
R-16
R-16
R-16
ADE7768
NOTES
Rev. A | Page 18 of 20
ADE7768
NOTES
Rev. A | Page 19 of 20
ADE7768
NOTES
© 2005 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective owners.
D05331–0–8/05(A)
Rev. A | Page 20 of 20