AD71056AR [ADI]
Energy Metering IC with Integrated Oscillator and Reverse Polarity Indication; 电能计量IC，集成振荡器和反向极性指示
| 型号： | AD71056AR |
| 厂家： | 
ADI |
| 描述： | Energy Metering IC with Integrated Oscillator and Reverse Polarity Indication |
| 文件： | 总20页 (文件大小：412K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
Energy Metering IC with Integrated
Oscillator and Reverse Polarity Indication
AD71056
FEATURES
On-chip oscillator as clock source
The AD71056 specifications surpass the accuracy requirements
as quoted in the IEC62053-21 standard.
High accuracy, supports 50 Hz/60 Hz IEC62053-21
Less than 0.1% error over a dynamic range of 500 to 1
Supplies average real power on frequency outputs (F1, F2)
High frequency output (CF) calibrates and supplies
instantaneous real power
Logic output (REVP) indicates potential miswiring or
negative power
Direct drive for electromechanical counters and 2-phase
stepper motors (F1, F2)
The only analog circuitry used in the AD71056 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 in extreme environmental conditions.
The AD71056 supplies average real power information on F1
and F2, the low frequency outputs. These outputs either directly
drive an electromechanical counter or interface with an MCU.
The high frequency CF logic output, ideal for calibration
purposes, provides instantaneous real power information.
Proprietary ADCs and DSP 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 AD71056 includes a power supply monitoring circuit on
the VDD supply pin. The AD71056 remains inactive until the
supply voltage on VDD reaches approximately 4 V. If the supply
falls below 4 V, the AD71056 also remains inactive and the F1,
F2, and CF outputs are in their nonactive modes.
GENERAL DESCRIPTION
Internal phase matching circuitry ensures that the voltage and
current channels are phase matched, and the HPF in the current
channel eliminates dc offsets. An internal no load threshold
ensures that the AD71056 does not exhibit creep when no load
is present.
The AD710561 is a high accuracy, electrical energy metering IC
with a precise oscillator circuit that serves as a clock source to
the chip. The AD71056 eliminates the need for an external
crystal or resonator, thus reducing the overall cost of building a
meter with this IC. The chip directly interfaces with the shunt
resistor.
The part is available in a 16-lead, narrow body SOIC package.
FUNCTIONAL BLOCK DIAGRAM
V
AGND
DGND
13
DD
1
6
AD71056
POWER
SUPPLY MONITOR
SIGNAL
PROCESSING
BLOCK
V2P
V2N
2
3
...110101...
+
+
Σ-Δ
ADC
MULTIPLIER
PHASE
CORRECTION
LPF
...11011001...
4
5
V1N
V1P
Σ-Δ
ADC
Ф
HPF
DIGITAL-TO-FREQUENCY
CONVERTER
INTERNAL
OSCILLATOR
4kΩ
2.5V
REFERENCE
7
11
8
10
9
12
14
16
15
REF
RCLKIN
REVP CF
F1
S0
SCF
S1
F2
IN/OUT
Figure 1.
1 U.S. Patents 5,745,323; 5,760,617; 5,862,069; 5,872,469; others pending.
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 registeredtrademarks arethe property of their respective owners.
One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700
Fax: 781.461.3113
www.analog.com
©2006 Analog Devices, Inc. All rights reserved.
AD71056
TABLE OF CONTENTS
Features .............................................................................................. 1
Power Factor Considerations.................................................... 10
Nonsinusoidal Voltage and Current........................................ 10
Applications..................................................................................... 12
Analog Inputs ............................................................................. 12
Power Supply Monitor............................................................... 13
Internal Oscillator (OSC).......................................................... 15
Transfer Function....................................................................... 15
Selecting a Frequency for an Energy Meter Application...... 16
No Load Threshold .................................................................... 17
Negative Power Information..................................................... 17
Outline Dimensions....................................................................... 18
Ordering Guide .......................................................................... 18
General Description......................................................................... 1
Functional Block Diagram .............................................................. 1
Revision History ............................................................................... 2
Specifications..................................................................................... 3
Timing Characteristics ................................................................ 4
Absolute Maximum Ratings............................................................ 5
ESD Caution.................................................................................. 5
Terminology ...................................................................................... 6
Pin Configuration and Function Descriptions............................. 7
Typical Performance Characteristics ............................................. 8
Theory of Operation ...................................................................... 10
REVISION HISTORY
8/06—Revision A: Initial Version
Rev. A | Page 2 of 20
AD71056
SPECIFICATIONS
VDD = 5 V 5ꢀ, AGND = DGND = 0 V, on-chip reference, RCLKIN = 6.2 kΩ, 0.5ꢀ 50 ppm/°C, TMIN to TMAX = −40°C to +85°C, unless
otherwise noted.
Table 1.
Parameter
Value
Unit
Test Conditions/Comments
ACCURACY1, 2
Measurement Error1 on Channel V1
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
Phase Error1 Between Channels
V1 Phase Lead 37°
V1 Phase Lag 60°
AC Power Supply Rejection1
0.1
0.1
degrees max
degrees max
Power factor (PF) = 0.8 capacitive
PF = 0.5 inductive
Output Frequency Variation (CF)
0.2
0.3
% reading typ
% 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
DC Power Supply Rejection1
Output Frequency Variation (CF)
S0 = S1 = 1, V1 = 21.2 mV rms, V2 = 116.7 mV rms,
V
DD = 5 V 250 mV
ANALOG INPUTS3
Channel V1 Maximum Signal Level
Channel V2 Maximum Signal Level
Input Impedance (DC)
Bandwidth (–3 dB)
30
165
320
7
18
4
mV max
mV max
kΩ min
kHz nominal
mV max
V1P and V1N to AGND
V2P and V2N to AGND
OSC = 450 kHz, RCLKIN = 6.2 kΩ, 0.5% 50 ppmꢀ°C
OSC = 450 kHz, RCLKIN = 6.2 kΩ, 0.5% 50 ppmꢀ°C
ADC Offset Error1, 2
Gain Error1
% ideal typ
External 2.5 V reference, V1 = 21.2 mV rms,
V2 = 116.7 mV rms
OSCILLATOR FREQUENCY (OSC)
Oscillator Frequency Tolerance1
Oscillator Frequency Stability1
REFERENCE INPUT
450
12
30
kHz nominal
% reading typ
ppmꢀ°C typ
RCLKIN = 6.2 kΩ, 0.5% 50 ppmꢀ°C
REFINꢀOUT Input Voltage Range
2.65
2.25
10
V max
V min
pF max
2.45 V nominal
2.45 V nominal
Input Capacitance
ON-CHIP REFERENCE
Reference Error
Temperature Coefficient
LOGIC INPUTS4
2.45 V nominal
200
20
mV max
ppmꢀ°C typ
SCF, S0, S1
Input High Voltage, VINH
Input Low Voltage, VINL
Input Current, IIN
2.4
0.8
1
V min
VDD = 5 V 5%
VDD = 5 V 5%
Typically 10 nA, VIN = 0 V to VDD
V max
μA max
pF max
Input Capacitance, CIN
LOGIC OUTPUTS4
10
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)
4.5
0.5
V min
V max
ISOURCE = 10 mA, VDD = 5 V, ISINK = 10 mA, VDD = 5 V
ISOURCE = 5 mA, VDD = 5 V, ISINK = 5 mA, VDD = 5 V
4
0.5
10
V min
V max
% ideal typ
External 2.5 V reference, V1 = 21.2 mV rms,
V2 = 116.7 mV rms
Rev. A | Page 3 of 20
AD71056
Parameter
POWER SUPPLY
VDD
Value
Unit
Test Conditions/Comments
For specified performance
5 V − 5%
5 V + 5%
Typically 4 mA
4.75
5.25
5
V min
V max
mA max
IDD
1 See the Terminology section for an explanation of specifications.
2 See plots in the Typical Performance Characteristics section.
3 See the Analog Inputs section.
4 Sample tested during initial release and after any redesign or process change that may affect this parameter.
TIMING CHARACTERISTICS
VDD = 5 V 5ꢀ, AGND = DGND = 0 V, on-chip reference, RCLKIN = 6.2 kΩ, 0.5ꢀ 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
Specifications
Unit
Test Conditions/Comments
1
t1
120
ms
F1 and F2 pulse width (logic low).
t2
t3
t4
t5
t6
See Table 6
1ꢀ2 t2
90
See Table 7
2
sec
sec
ms
sec
μs
Output pulse period. See the Transfer Function section.
Time between F1 falling edge and F2 falling edge.
CF pulse width (logic high).
CF pulse period. See the Transfer Function section.
Minimum time between F1 and F2 pulses.
1, 2
1 The pulse widths of F1, F2, and CF are not fixed for higher output frequencies. See the Frequency Outputs section.
2 The CF pulse is always 35 μs in high frequency mode. See the Frequency Outputs section and Table 7.
Timing Diagram
t1
F1
t6
t2
F2
t3
t4
t5
CF
Figure 2. Timing Diagram for Frequency Outputs
Rev. A | Page 4 of 20
AD71056
ABSOLUTE MAXIMUM RATINGS
TA = 25°C, unless otherwise noted.
Table 3.
Stresses above those listed under Absolute Maximum Ratings
may cause permanent damage to the device. This is a stress
rating only; 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.
Parameter
Rating
VDD to AGND
VDD to DGND
−0.3 V to +7 V
−0.3 V to +7 V
Analog Input Voltage to AGND
V1P, V1N, V2P, and V2N
−6 V to +6 V
Reference Input Voltage to AGND
Digital Input Voltage to DGND
Digital Output Voltage to DGND
Operating Temperature Range
Storage Temperature Range
Junction Temperature
−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
16-Lead Plastic SOIC, Power Dissipation
θJA Thermal Impedance1
Package Temperature Soldering
350 mW
124.9°CꢀW
See J-STD-20
1 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
AD71056
TERMINOLOGY
Measurement Error
ADC Offset Error
The error associated with the energy measurement made by the
AD71056 is defined by the following formula:
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.
Energy Registered by AD71056 −True Energy
ꢀError =
×100ꢀ
True Energy
Frequency Output Error (CF)
The frequency output error of the AD71056 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 AD71056 transfer function. See
Figure 14 for a typical distribution of part-to-part variation of
CF frequency.
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 phase correction
network is also placed in Channel V1. The phase correction
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 23
and Figure 24).
Gain Error
The gain error of the AD71056 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 output of the ADCs.
Power Supply Rejection (PSR)
This quantifies the AD71056 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.
Oscillator Frequency Tolerance
The oscillator frequency tolerance of the AD71056 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 as defined in the Specifications section.
For the dc PSR measurement, a reading at nominal supplies
(5 V) is taken. The supplies are then varied 5ꢀ and a second
reading is obtained with the same input signal levels. Any error
introduced is, again, expressed as a percentage of reading.
Oscillator Frequency Stability
Oscillator frequency stability is defined as the 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
AD71056
PIN CONFIGURATION AND FUNCTION DESCRIPTIONS
V
1
2
3
4
5
6
7
8
16 F1
DD
V2P
V2N
15 F2
14 CF
AD71056
V1N
13 DGND
12 REVP
11 RCLKIN
10 S0
TOP VIEW
(Not to Scale)
V1P
AGND
REF
IN/OUT
SCF
9
S1
Figure 3. Pin Configuration
Table 4. Pin Function Descriptions
Pin No. Mnemonic Description
1
VDD
Power Supply. This pin provides the supply voltage for the circuitry in the AD71056. Maintain the supply
voltage at 5 V 5% for specified operation. Decouple this pin with a 10 ꢁF capacitor in parallel with a ceramic
100 nF capacitor.
2, 3
V2P, V2N
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.
4, 5
6
V1N, V1P
AGND
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.
Analog Ground. This pin provides the ground reference for the analog circuitry in the AD71056, that is, the ADCs
and reference. Tie this pin 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, connect the analog ground plane to the digital ground plane at only one point. A
star ground configuration helps to keep noisy digital currents away from the analog circuits.
7
REFINꢀOUT
Reference Voltage. The on-chip reference has a nominal value of 2.45 V and a typical temperature coefficient
of 20 ppmꢀ°C. An external reference source can also be connected at this pin. In either case, decouple this pin
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.
8
SCF
Select Calibration Frequency. This logic input selects the frequency on the Calibration Output CF. Table 7
shows calibration frequency selections.
9, 10
S1, S0
Conversion Frequency Logic Input Selection. These logic inputs 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. Table 5 shows conversion frequency selections.
11
12
RCLKIN
REVP
On-Chip Clock Enabler. 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.
Negative Power Indicator. This logic output goes high when negative power is detected, such as 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.
13
DGND
Digital Ground. This pin provides the ground reference for the digital circuitry in the AD71056, that is, the
multiplier, filters, and digital-to-frequency converter. Tie this pin to the digital ground plane of the PCB. The
digital ground plane is the ground reference for all digital circuitry, for example, counters (mechanical and
digital), MCUs, and indicator LEDs. For accurate noise suppression, connect the analog ground plane to the
digital ground plane at one point only—a star ground.
14
CF
Calibration Frequency Logic Output. The CF logic output provides instantaneous real power information. This
output is for calibration purposes (also see the SCF pin description).
15, 16
F2, F1
Low Frequency Logic Outputs. F1 and F2 supply average 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
AD71056
TYPICAL PERFORMANCE CHARACTERISTICS
V
DD
+
100nF
10µF
1
K7
K8
V
DD
U3
602kΩ
200Ω
F1 16
4
1
2
3
V2P
150nF
15
14
220V
F2
U1
AD71056
CF
2
3
200Ω
V2N
40A TO
PS2501-1
150nF
40mA
820Ω
12
11
REVP
200Ω
6.2kΩ
5
4
V1P
V1N
RCLKIN
+
150nF
V
DD
350µΩ
200Ω
10kΩ
150nF
100nF
10
9
S0
S1
7
REF
IN/OUT
+
8
SCF
1µF
10nF
10nF
10nF
AGND DGND
13
6
Figure 4. Test Circuit for Performance Curves
1.0
0.8
0.6
0.4
0.2
0
1.0
PF = 1
ON-CHIP REFERENCE
PF = 1
EXTERNAL REFERENCE
0.8
0.6
0.4
0.2
0
+85°C
–40°C
+25°C
+25°C
+85°C
–0.2
–0.4
–0.6
–0.8
–1.0
–0.2
–0.4
–0.6
–0.8
–1.0
–40°C
0.1
1
10
100
0.1
1
10
100
CURRENT CHANNEL (% of Full Scale)
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
EXTERNAL REFERENCE
PF = 0.5 IND
ON-CHIP REFERENCE
0.8
0.6
0.4
0.2
0
0.8
0.6
0.4
0.2
0
+85°C, PF = 0.5 IND
+25°C, PF = 1
–40°C, PF = 0.5 IND
+25°C, PF = 1
–0.2
–0.4
–0.6
–0.8
–1.0
–0.2
–0.4
–0.6
–0.8
–1.0
+25°C, PF = 0.5 IND
+85°C, PF = 0.5 IND
–40°C, PF = 0.5 IND
+25°C, PF = 0.5 IND
0.1
1
10
100
0.1
1
10
100
CURRENT CHANNEL (% of Full Scale)
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
AD71056
0.5
0.4
40
DISTRIBUTION CHARACTERISTICS
MEAN = 2.247828
EXTERNAL REFERENCE
TEMPERATURE = 25°C
SDs = 1.367176
MIN = –2.09932
MAX = +5.28288
0.3
30 NO. OF POINTS = 100
0.2
PF = 0.5 IND
PF = 1
0.1
0
20
10
0
–0.1
–0.2
–0.3
–0.4
–0.5
PF = 0.5 CAP
–5 –4 –3 –2 –1
0
1
2
3
4
5
6
7
8
9
45
50
55
FREQUENCY (Hz)
60
65
CHANNEL V1 OFFSET (mV)
Figure 12. Channel V1 Offset Distribution
Figure 9. Error as a % of Reading over Input Frequency
1.0
50
40
30
20
10
0
PF = 1
DISTRIBUTION CHARACTERISTICS
MEAN = –1.563484
0.8
0.6
0.4
0.2
0
ON-CHIP REFERENCE
SDs = 2.040699
EXTERNAL REFERENCE
TEMPERATURE = 25°C
MIN = –6.82969
MAX = +2.6119
NO. OF POINTS = 100
5.25V
5V
4.75V
–0.2
–0.4
–0.6
–0.8
–1.0
0.1
1
10
100
–12 –10 –8 –6 –4 –2
0
2
4
6
8
10 12
CURRENT CHANNEL (% of Full Scale)
CHANNEL V2 OFFSET (mV)
Figure 10. PSR with On-Chip Reference, PF = 1
Figure 13. Channel V2 Offset Distribution
1.0
0.8
0.6
0.4
0.2
0
1000
800
600
400
200
0
DISTRIBUTION CHARACTERISTICS
MEAN = 0%
PF = 1
EXTERNAL REFERENCE
EXTERNAL REFERENCE
TEMPERATURE = 25°C
SDs = 1.55%
MIN = –11.79%
MAX = +6.08%
NO. OF POINTS = 3387
5.25V
5V
–0.2
–0.4
–0.6
–0.8
–1.0
4.75V
0.1
1
10
100
–10 –8 –6 –4 –2
0
2
4
6
8
10 12
CURRENT CHANNEL (% of Full Scale)
DEVIATION FROM MEAN (%)
Figure 11. PSR with External Reference, PF = 1
Figure 14. Part-to-Part CF Distribution from Mean of CF
Rev. A | Page 9 of 20
AD71056
THEORY OF OPERATION
The two ADCs in the AD71056 digitize the voltage signals from
the current and voltage sensors. These ADCs are 16-bit, Σ-Δ
with an oversampling rate of 450 kHz. This analog input struc-
ture greatly simplifies sensor interfacing by providing a wide
dynamic range for direct connection to the sensor and also
simplifies 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.
POWER FACTOR CONSIDERATIONS
The method used to extract the real power information from
the instantaneous power signal (that is, by low-pass filtering) is
valid even when the voltage and current signals are not in
phase. Figure 16 displays the unity power factor condition and
a displacement power factor (DPF) = 0.5; that is, the current
signal lagging the voltage by 60°. Assuming the voltage and
current waveforms are sinusoidal, the real power component of
the instantaneous power signal (the dc term) is given by
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 (that is, 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 is extracted by low-pass filtering the
instantaneous power signal. 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.
V × I
2
⎛
⎜
⎞
⎟
× cos
(
60°
)
(1)
⎝
⎠
This is the correct real power calculation.
INSTANTANEOUS
POWER SIGNAL
INSTANTANEOUS REAL
POWER SIGNAL
POWER
V × I
2
0V
TIME
DIGITAL-TO-
FREQUENCY
CURRENT
AND
F1
VOLTAGE
CH1
CH2
ADC
F2
HPF
INSTANTANEOUS REAL
POWER SIGNAL
POWER
INSTANTANEOUS
POWER SIGNAL
MULTIPLIER
DIGITAL-TO-
FREQUENCY
LPF
ADC
CF
V × I
2
COS (60°)
0V
INSTANTANEOUS
POWER SIGNAL – p(t)
INSTANTANEOUS REAL
POWER SIGNAL
TIME
VOLTAGE
CURRENT
60°
Figure 16. DC Component of Instantaneous Power Signal Conveys
Real Power Information, PF < 1
TIME
TIME
Figure 15. Signal Processing Block Diagram
NONSINUSOIDAL VOLTAGE AND CURRENT
The real power calculation method also holds true for non-
sinusoidal 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.
The low frequency outputs (F1, F2) of the AD71056 are
generated by accumulating this 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 real power. This
average real power information is then accumulated (for
example, by a counter) to generate real energy information.
Conversely, due to its high output frequency and, hence, shorter
integration time, the CF output frequency is proportional to the
instantaneous real power. This is useful for system calibration
that can be done faster under steady load conditions.
∞
v(t) = V0 + 2 × V × sin
(hω t + αh
)
(2)
∑
h
h≠0
where:
v(t) is the instantaneous voltage.
V0 is the average value.
Vh is the rms value of Voltage Harmonic h.
αh is the phase angle of the voltage harmonic.
Rev. A | Page 10 of 20
AD71056
∞
∑
(3)
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 the case of 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.
i(t) = I
+
2 ×
I
× sin
(
hωt + β
)
0
h
h
h ≠ o
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.
Note that the input bandwidth of the analog inputs is 7 kHz at
the nominal internal oscillator frequency of 450 kHz.
Using Equation 2 and Equation 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 × I1 cos ϕ1
(4)
(5)
ϕ1 = α1 − β1
and PH
∞
P = V × Ih cos ϕh
∑
H
h
h≠1
ϕh = αh − βh
Rev. A | Page 11 of 20
AD71056
APPLICATIONS
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
AD71056 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.
ANALOG INPUTS
Channel V1 (Current Channel)
The voltage output from the current sensor is connected to the
AD71056 at Channel V1. 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 ±±0 mV (21 mV rms for a pure sinusoidal signal)
for specified operation.
Typical Connection Diagrams
Figure 19 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.
V1
+30mV
V1P
V1N
R
V1P
F
DIFFERENTIAL INPUT
V1
±30mV MAX PEAK
C
F
V
CM
SHUNT
V1N
±30mV
COMMON MODE
±6.25mV MAX
V
CM
C
R
F
F
AGND
–30mV
AGND
PHASE NEUTRAL
Figure 17. Maximum Signal Levels, Channel V1
Figure 19. Typical Connection for Channel V1
Figure 17 illustrates the maximum signal levels on V1P and
V1N. The maximum differential voltage is ±±0 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, as shown in Figure 17.
Figure 20 shows a typical connection for Channel V2. Typically,
the AD71056 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.
Channel V2 (Voltage Channel)
R
B
1
R
V2P
A
The output of the line voltage sensor is connected to the
AD71056 at Channel V2. Channel V2 is a fully differential
voltage input with a maximum peak differential signal of ±165 mV.
±165mV
R
C
F
F
V2N
R
C
F
F
Figure 18 illustrates the maximum signal levels that can be
connected to the AD71056 Channel V2.
NEUTRAL PHASE
1
R
>> R + R .
B F
A
V2
Figure 20. Typical Connections for Channel V2
+165mV
V2P
V2N
DIFFERENTIAL INPUT
V2
±165mV MAX PEAK
V
CM
COMMON MODE
±25mV MAX
V
CM
AGND
–165mV
Figure 18. Maximum Signal Levels, Channel V2
Rev. A | Page 12 of 20
AD71056
Equation 6 shows how the power calculation is affected by the
dc offsets in the current and voltage channels.
POWER SUPPLY MONITOR
The AD71056 contains an on-chip power supply monitor. The
power supply (VDD) is continuously monitored by the AD71056.
If the supply is less than 4 V, the AD71056 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 that provide a high degree of immunity
to false triggering from noisy supplies.
V cos
(
ωt
)
+VOS
×
I cos
(
ωt
)
+ IOS
ωt
(6)
V × I
=
+
+VOS × IOS +VOS × I cos
(
)
+ IOS ×V cos ωt
( )
2
V × I
× cos 2ωt
( )
2
In Figure 21, the trigger level is nominally set at 4 V. The
tolerance on this trigger level is within 5ꢀ. The power supply
and decoupling for the part should be such that the ripple at
VDD does not exceed 5 V 5ꢀ as specified for normal
operation.
The HPF in Channel V1 has an associated phase response that
is compensated for on chip. Figure 23 and Figure 24 show the
phase error between channels with the compensation network
activated. The AD71056 is phase compensated up to 1 kHz as
shown. This ensures correct active harmonic power calculation
even at low power factors.
V
DD
5V
4V
0.30
0.25
0.20
0.15
0.10
0.05
0
0V
TIME
INTERNAL
ACTIVATION
INACTIVE
ACTIVE
INACTIVE
Figure 21. On-Chip Power Supply Monitor
–0.05
–0.10
HPF and Offset Effects
Figure 22 illustrates 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).
0
100 200 300 400 500 600 700 800 900 1000
FREQUENCY (Hz)
Figure 23. Phase Error Between Channels (0 Hz to 1 kHz)
0.30
0.25
0.20
0.15
0.10
0.05
0
DC COMPONENT (INCLUDING ERROR TERM)
IS EXTRACTED BY THE LPF FOR REAL
POWER CALCULATION
–0.05
–0.10
V
× I
OS
OS
V × I
2
40
45
50
55
60
65
70
FREQUENCY (Hz)
Figure 24. Phase Error Between Channels (40 Hz to 70 Hz)
I
× V
OS
V
× I
OS
0
FREQUENCY (RAD/s)
Figure 22. Effect of Channel Offset on the Real Power Calculation
Rev. A | Page 13 of 20
AD71056
This higher output frequency is generated by accumulating the
instantaneous 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 to
remove any ripple. If CF is being used to measure energy, for
example in a microprocessor-based application, the CF output
should also be averaged to calculate power.
Digital-to-Frequency Conversion
As previously described, the digital output of the low-pass
filter after multiplication contains the 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
H
(
f
)
=
(7)
f 2
1 +
Because the F1 and F2 outputs operate at a much lower
frequency, a lot more averaging of the instantaneous real power
signal is carried out. The result is a greatly attenuated sinusoidal
content and a virtually ripple free frequency output.
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.
Connecting to a Microcontroller for Energy
Measurement
The easiest way to interface the AD71056 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 26 illustrates one scheme to digitize the output frequency
and carry out the necessary averaging mentioned in the Digital-
to-Frequency Conversion section.
Figure 25 shows the instantaneous 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
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 real
power signal. The average value of a sinusoidal signal is zero.
Thus, the frequency generated by the AD71056 is proportional
to the average real power. Figure 25 shows the digital-to-
frequency conversion for steady load conditions, that is,
constant voltage and current.
CF
FREQUENCY
RIPPLE
AVERAGE
FREQUENCY
±10%
F1
DIGITAL-TO-
FREQUENCY
F1
TIME
V
F2
TIME
MCU
MULTIPLIER
DIGITAL-TO-
AD71056
LPF
CF
FREQUENCY
COUNTER
CF
I
CF
LPF TO EXTRACT
REAL POWER
(DC TERM)
TIMER
TIME
V × I
2
COS (2ω)
ATTENUATED BY LPF
Figure 26. Interfacing the AD71056 to an MCU
As shown, the frequency output CF is connected to an MCU
counter or port. This counts the number of pulses in a given
integration time that is determined by an MCU internal timer.
The average power proportional to the average frequency is
given by
ω
0
2ω
FREQUENCY (RAD/s)
INSTANTANEOUS REAL POWER SIGNAL
(FREQUENCY DOMAIN)
Figure 25. Real Power-to-Frequency Conversion
Counter
Time
Figure 25 shows that 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
real power signal. The output frequency on CF can be up to
2048 times higher than the frequency on F1 and F2.
Average Frequency = Average Power =
(8)
Rev. A | Page 14 of 20
AD71056
TRANSFER FUNCTION
The energy consumed during an integration period is given by
Frequency Outputs F1 and F2
Counter
(9)
Energy = Average Power ×Time =
× Time = Counter
The AD71056 calculates the product of two voltage signals
(on Channel V1 and Channel V2) and then low-pass filters this
product to extract real power information. This 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 real power information accumulated over a
relatively long period of time. The result is an output frequency
that is proportional to the average real power. The averaging of
the 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:
Time
For the purpose of calibration, this integration time can be as
long as 10 seconds to 20 seconds to accumulate enough pulses
to ensure correct averaging of the frequency. In normal operation,
the integration time can be reduced to one or two 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 can 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 that depends on the load as well as the integration
period used in the MCU to determine average power. For
example, at light loads, the output frequency may be 10 Hz.
With an integration period of two seconds, only about 20 pulses
are counted. The possibility of missing one pulse always exists,
because the output frequency of the AD71056 is running
asynchronously to the MCU timer. This results in a 1-in-20, or
5%, error in the power measurement.
494.75×V1rms ×V2rms × f1...4
(10)
Freq =
2
VREF
where:
Freq = output frequency on F1 and F2 (Hz).
V1rms = differential rms voltage signal on Channel V1 (V).
V2rms = differential rms voltage signal on Channel V2 (V).
V
REF = the reference voltage (2.45 V ±200 mV) (V).
f
1…4 = one of four possible frequencies selected by using
INTERNAL OSCILLATOR (OSC)
Logic Input S0 and Logic Input S1 (see Table 5).
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
temperature drift to ensure stability and linearity of the chip.
The oscillator frequency is inversely proportional to the
RCLKIN, as shown in Figure 27. 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 27, is recommended.
Table 5. f1…4 Frequency Selection
S1
S0
OSC Relation1
OSC/219
f1…4 at Nominal OSC (Hz)2
0
0
1
0
0.86
1.72
3.43
6.86
1
OSC/218
0
OSC/217
1
1
OSC/216
1 f1…4 is a binary fraction of the internal oscillator frequency (OSC).
2 Values are generated using the nominal frequency of 450 kHz.
Example
490
480
470
460
450
440
430
420
410
400
In this example, with ac voltages of ±±0 mV peak applied to
V1 and ±165 mV peak applied to V2, the expected output
frequency is calculated as
f
1…4 = OSC/219 Hz, S0 = S1 = 0
V1rms = 0.0±/√2 V
V2rms = 0.165/√2 V
V
REF = 2.45 V (nominal reference value)
Note that if the on-chip reference is used, actual output
frequencies can vary from device to device due to the reference
tolerance of ±200 mV.
5.8
5.9
6.0
6.1
6.2
6.3
6.4
6.5
6.6
6.7
494.75×0.0±×0.165× f1
Freq =
= 0.204 × f1 = 0.175
(11)
RESISTANCE (kΩ)
2 × 2 ×2.452
Figure 27. Effect of RCLKIN on Internal Oscillator Frequency (OSC)
Rev. A | Page 15 of 20
AD71056
Table 6. Maximum Output Frequency on the F1 and F2 Pins
S1 S0 OSC Relation Max Frequency1 or AC Inputs (Hz)
Table 8. F1 and F2 Frequency at 100 imp/kWh
IMAX (A)
F1 and F2 (Hz)
0
0
1
1
0
1
0
1
0.204 × f1
0.204 × f2
0.204 × f3
0.204 × f4
0.175
0.35
0.70
1.40
12.5
25.0
40.0
60.0
0.076
0.153
0.244
0.367
1 Values are generated using the nominal frequency of 450 kHz.
80.0
0.489
120.0
0.733
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 the F1 and F2 pins. The lower the
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 for 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 lists the output frequency on the F1 and F2 pins when
both analog inputs are half-scale. The frequencies listed in Table 9
align very well with those listed in Table 8 for maximum load.
f
1…4 frequency selected, the higher the CF scaling (except for the
high frequency mode where 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 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 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 real
power signal, the CF output is much more responsive to power
fluctuations (see the signal processing block in Figure 15).
Table 9. F1 and F2 Frequency with Half-Scale AC Inputs
Frequency on F1 and F2—
S1 S0 f1…4 (Hz)
CH1 and CH2 Half-Scale AC Input1
0
0
1
1
0
1
0
1
0.86
1.72
3.43
6.86
0.044 Hz
0.088 Hz
0.176 Hz
0.352 Hz
0.051 × f1
0.051 × f2
0.051 × f3
0.051 × f4
Table 7. Maximum Output Frequency on CF
SCF
S1
S0
CF Max for AC Signals (Hz)1
128 × F1, F2 = 22.4
64 × F1, F2 = 11.2
1 Values are generated using the nominal frequency of 450 kHz.
1
0
0
0
0
0
When selecting a suitable f1…4 frequency for a meter design,
compare the frequency output at IMAX (maximum load) based
on a meter constant of 100 imp/kWh against the last column 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 the F1 and F2 pins with a meter constant of
100 imp/kWh is 0.153 Hz at 25 A and 220 V (from Table 8). In
the last column of Table 9, the closest frequency to 0.153 Hz is
0.176 Hz. Therefore, f3 (3.43 Hz) is selected for this design (see
Table 5).
1
0
1
64 × F1, F2 = 22.4
0
0
1
32 × F1, F2 = 11.2
1
1
0
32 × F1, F2 = 22.4
0
1
0
16 × F1, F2 = 11.2
1
1
1
16 × F1, F2 = 22.4
0
1
1
2048 × F1, F2 = 2.867 kHz
1 Values are generated using the nominal frequency of 450 kHz.
SELECTING A FREQUENCY FOR AN ENERGY
METER APPLICATION
As listed in Table 5, the user can select one of four frequencies.
This frequency selection determines the maximum frequency
on the F1 and F2 pins. 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 is optimized for a meter constant of
100 imp/kWh with a maximum current between 10 A and
120 A. Table 8 shows the output frequency for several maxi-
mum currents (IMAX) with a line voltage of 220 V. In all cases,
the meter constant is 100 imp/kWh.
Frequency Outputs
Figure 2 shows a timing diagram for the various frequency
outputs. The outputs (F1 and F2) are the low frequency outputs
that can be used to directly drive a stepper motor or electro-
mechanical 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 high frequency CF output is intended to be used for
communications and calibration purposes. CF produces a
90-ms-wide active high pulse (t4) at a frequency proportional
Rev. A | Page 16 of 20
AD71056
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. If the CF frequency,
for example, is 20 Hz, the CF pulse width is 25 ms.
output frequency at F1 or F2 equals 0.00244ꢀ of 3.43 Hz or
8.38 × 10–5 Hz. This is 2.68 × 10–3 Hz at CF (32 × F1 Hz) when
SCF = S0 = 1, S1 = 0. In this example, the no load threshold is
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 that
states the meter must start up with a load equal to or less than
0.4ꢀ Ib. For a 5 A (Ib) meter, 0.4ꢀ of Ib is equivalent to 20 mA.
When the high frequency mode is selected (that is, SCF = 0,
S1 = S0 = 1), the CF pulse width is fixed at 35 μs. Therefore, t4
is always 35 μs, regardless of the output frequency on CF.
NEGATIVE POWER INFORMATION
NO LOAD THRESHOLD
The AD71056 detects when the current and voltage channels
have a phase shift greater than 90°. This mechanism can detect
wrong connection of the meter or generation of negative power.
The AD71056 also includes a no load threshold and start-up
current feature that eliminates any creep effects in the meter.
The AD71056 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 0.00244ꢀ
for each of the f1…4 frequency selections (see Table 5).
The REVP pin output goes active high when negative power is
detected and active low when positive power is detected. The
REVP pin output changes state as a pulse is issued on CF.
For example, for an energy meter with a meter constant of
100 imp/kWh on F1, F2 using f3 (3.43 Hz), the minimum
Rev. A | Page 17 of 20
AD71056
OUTLINE DIMENSIONS
10.00 (0.3937)
9.80 (0.3858)
9
8
16
1
6.20 (0.2441)
5.80 (0.2283)
4.00 (0.1575)
3.80 (0.1496)
1.27 (0.0500)
BSC
0.50 (0.0197)
0.25 (0.0098)
45°
1.75 (0.0689)
1.35 (0.0531)
0.25 (0.0098)
0.10 (0.0039)
8°
0°
COPLANARITY
0.10
SEATING
PLANE
1.27 (0.0500)
0.40 (0.0157)
0.51 (0.0201)
0.31 (0.0122)
0.25 (0.0098)
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 28. 16-Lead Standard Small Outline Package [SOIC_N]
Narrow Body (R-16)
Dimensions shown in millimeters and (inches)
ORDERING GUIDE
Model
AD71056AR
AD71056AR-RL
AD71056ARZ1
AD71056ARZ-RL1
Temperature Range
Package Description
16-Lead SOIC_N
16-Lead SOIC_N, Reel
16-Lead SOIC_N
Package Option
−40°C to +85°C
−40°C to +85°C
−40°C to +85°C
−40°C to +85°C
R-16
R-16
R-16
R-16
16-Lead SOIC_N, Reel
1 Z = Pb-free part.
Rev. A | Page 18 of 20
AD71056
NOTES
Rev. A | Page 19 of 20
AD71056
NOTES
©2006 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective owners.
D05636-0-8/06(A)
Rev. A | Page 20 of 20
相关型号：
AD7111ABCHIPS
IC PARALLEL, 8 BITS INPUT LOADING, 8-BIT DAC, UUC, DIE, Digital to Analog Converter
ADI
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