AD637ARBR [ADI]
RMS TO DC CONVERTER, 0.15MHz, PDSO16;
| 型号： | AD637ARBR |
| 厂家： | 
ADI |
| 描述： | RMS TO DC CONVERTER, 0.15MHz, PDSO16 光电二极管 转换器 |
| 文件： | 总20页 (文件大小：607K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
High Precision, Wideband
RMS-to-DC Converter
AD637
FUNCTIONAL BLOCK DIAGRAM
FEATURES
High accuracy
0.02% maximum nonlinearity, 0 V to 2 V rms input
0.10% additional error to crest factor of 3
Wide bandwidth
8 MHz at 2 V rms input
600 kHz at 100 mV rms
BUFF IN
BUFF
OUT
25kΩ
RMS OUT
ABSOLUTE
VALUE
SQUARER/
DIVIDER
V
IN
Computes
True rms
Square
C
25kΩ
AV
DEN INPUT
dB OUTPUT
Mean square
Absolute value
dB output (60 dB range)
OUTPUT
OFFSET
BIAS
Chip select/power-down feature allows
Analog three-state operation
Quiescent current reduction from 2.2 mA to 350 μA
14-lead SBDIP, 14-lead low cost CERDIP, and 16-lead SOIC_W
COMMON
CS
AD637
Figure 1.
GENERAL DESCRIPTION
The AD637 is a complete, high accuracy, monolithic rms-to-dc
converter that computes the true rms value of any complex
waveform. It offers performance that is unprecedented in
integrated circuit rms-to-dc converters and comparable to
discrete and modular techniques in accuracy, bandwidth, and
dynamic range. A crest factor compensation scheme in the
AD637 permits measurements of signals with crest factors of
up to 10 with less than 1% additional error. The wide band-
width of the AD637 permits the measurement of signals up to
600 kHz with inputs of 200 mV rms and up to 8 MHz when the
input levels are above 1 V rms.
The input circuitry of the AD637 is protected from overload
voltages in excess of the supply levels. The inputs are not
damaged by input signals if the supply voltages are lost.
The AD637 is available in accuracy Grade J and Grade K for
commercial temperature range (0°C to 70°C) applications, accuracy
Grade A and Grade B for industrial range (−40°C to +85°C) appli-
cations, and accuracy Grade S rated over the −55°C to +125°C
temperature range. All versions are available in hermetically sealed,
14-lead SBDIP, 14-lead CERDIP, and 16-lead SOIC_W packages.
The AD637 computes the true root mean square, mean square,
or absolute value of any complex ac (or ac plus dc) input
waveform and gives an equivalent dc output voltage. The true
rms value of a waveform is more useful than an average
rectified signal because it relates directly to the power of the
signal. The rms value of a statistical signal is also related to the
standard deviation of the signal.
As with previous monolithic rms converters from Analog
Devices, Inc., the AD637 has an auxiliary dB output available to
users. The logarithm of the rms output signal is brought out to a
separate pin, allowing direct dB measurement with a useful
range of 60 dB. An externally programmed reference current
allows the user to select the 0 dB reference voltage to correspond to
any level between 0.1 V and 2.0 V rms.
The AD637 is laser wafer trimmed to achieve rated performance
without external trimming. The only external component
required is a capacitor that sets the averaging time period. The
value of this capacitor also determines low frequency accuracy,
ripple level, and settling time.
A chip select connection on the AD637 permits the user to
decrease the supply current from 2.2 mA to 350 μA during periods
when the rms function is not in use. This feature facilitates the
addition of precision rms measurement to remote or handheld
applications where minimum power consumption is critical. In
addition, when the AD637 is powered down, the output goes to a
high impedance state. This allows several AD637s to be tied
together to form a wideband true rms multiplexer.
The on-chip buffer amplifier can be used either as an input
buffer or in an active filter configuration. The filter can be used
to reduce the amount of ac ripple, thereby increasing accuracy.
Rev. K
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
©2011 Analog Devices, Inc. All rights reserved.
AD637
TABLE OF CONTENTS
Features .............................................................................................. 1
Choosing the Averaging Time Constant....................................9
Frequency Response .................................................................. 11
AC Measurement Accuracy and Crest Factor........................ 12
Connection for dB Output........................................................ 12
dB Calibration............................................................................. 13
Low Frequency Measurements................................................. 14
Vector Summation ..................................................................... 14
Evaluation Board ............................................................................ 16
Outline Dimensions....................................................................... 19
Ordering Guide .......................................................................... 20
Functional Block Diagram .............................................................. 1
General Description......................................................................... 1
Revision History ............................................................................... 2
Specifications..................................................................................... 3
Absolute Maximum Ratings............................................................ 5
ESD Caution.................................................................................. 5
Pin Configurations and Function Descriptions ........................... 6
Functional Description.................................................................... 7
Standard Connection................................................................... 8
Chip Select..................................................................................... 8
Optional Trims for High Accuracy............................................ 8
REVISION HISTORY
2/11—Rev. J to Rev. K
4/05—Rev. F to Rev. G
Changes to Figure 15...................................................................... 11
Changes to Figure 16...................................................................... 12
Changes to Evaluation Board Section and Figure 23................. 16
Added Figure 24; Renumbered Sequentially .............................. 17
Changes to Figure 25 Through Figure 29.................................... 17
Changes to Figure 30...................................................................... 18
Added Figure 31.............................................................................. 18
Deleted Table 6; Renumbered Sequentially ................................ 18
Changes to Ordering Guide .......................................................... 20
Updated Format..................................................................Universal
Changes to Figure 1...........................................................................1
Changes to General Description .....................................................1
Deleted Product Highlights .............................................................1
Moved Figure 4 to Page ....................................................................8
Changes to Figure 5...........................................................................9
Changes to Figure 8........................................................................ 10
Changes to Figure 11, Figure 12, Figure 13, and Figure 14....... 11
Changes to Figure 19...................................................................... 14
Changes to Figure 20...................................................................... 14
Changes to Figure 21...................................................................... 16
Updated Outline Dimensions....................................................... 17
Changes to Ordering Guide.......................................................... 18
4/07—Rev. I to Rev. J
Added Evaluation Board Section ................................................. 16
Updated Outline Dimensions....................................................... 20
10/06—Rev. H to Rev. I
3/02—Rev. E to Rev. F
Edits to Ordering Guide ...................................................................3
Changes to Table 1............................................................................ 3
Changes to Figure 4.......................................................................... 7
Changes to Figure 7.......................................................................... 9
Changes to Figure 16, Figure 18, and Figure 19 ......................... 12
Changes to Figure 20...................................................................... 13
12/05—Rev. G to Rev. H
Updated Format..................................................................Universal
Changes to Figure 1.......................................................................... 1
Changes to Figure 11...................................................................... 10
Updated Outline Dimensions....................................................... 16
Changes to Ordering Guide .......................................................... 17
Rev. K | Page 2 of 20
AD637
SPECIFICATIONS
At 25°C and 15 V dc, unless otherwise noted.1
Table 1.
AD637J/AD637A
AD637K/AD637B
AD637S
Typ
Parameter
Min
Typ
Max
Min
Typ
Max
Min
Max
Unit
TRANSFER FUNCTION
2
2
2
VOUT
=
avg ×(VIN
)
VOUT
=
avg ×(VIN
)
VOUT
=
avg ×(VIN )
CONVERSION ACCURACY
Total Error, Internal Trim2
(Figure 5)
1
0.5
3.0 0.6
150
0.5 0.2
2.0 0.3
1
0.5 mV ±± of
reading
TMIN to TMAX
6
0.7 mV ± ± of
reading
vs. Supply
+VIN = 300 mV
30
30
150
300
0.1
30
150
300
0.25
μV/V
μV/V
vs. Supply
−VIN = −300 mV
100
300
100
100
DC Reversal
Error at 2 V
0.25
± of
reading
Nonlinearity 2 V Full Scale3
Nonlinearity 7 V Full Scale
Total Error, External Trim
0.04
0.05
0.02
0.05
0.04
0.05
± of FSR
± of FSR
±0.5 ± 0.1
±0.25 ± 0.05
±0.5 ± 0.1
mV ± ± of
reading
ERROR VS. CREST FACTOR4
Crest Factor 1 to 2
Specified accuracy
±0.1
Specified accuracy
±0.1
Specified accuracy
±0.1
Crest Factor = 3
± of
reading
Crest Factor = 10
±1.0
25
±1.0
25
±1.0
25
± of
reading
AVERAGING TIME CONSTANT
INPUT CHARACTERISTICS
Signal Range, ±15 V Supply
Continuous RMS Level
Peak Transient Input
ms/μF CAV
0 to 7
0 to 7
0 to 7
V rms
V p-p
±15
±15
±15
Signal Range, ±5 V Supply
Continuous RMS Level
Peak Transient Input
0 to 4
0 to 4
0 to 4
V rms
V p-p
V p-p
±ꢀ
±ꢀ
±ꢀ
Maximum Continuous
Nondestructive
±15
±15
±15
Input Level
(All Supply Voltages)
Input Resistance
ꢀ.4
8
9.ꢀ
ꢀ.4
8
9.ꢀ
ꢀ.4
8
9.ꢀ
kΩ
Input Offset Voltage
FREQUENCY RESPONSE5
±0.5
±0.2
±0.5
mV
Bandwidth for 1±
Additional Error
(0.09 dB)
VIN = 20 mV
VIN = 200 mV
VIN = 2 V
11
11
11
kHz
kHz
kHz
ꢀꢀ
ꢀꢀ
ꢀꢀ
200
200
200
±3 dB Bandwidth
VIN = 20 mV
VIN = 200 mV
VIN = 2 V
150
1
150
1
150
1
kHz
MHz
MHz
8
8
8
Rev. K | Page 3 of 20
AD637
AD637J/AD637A
AD637K/AD637B
AD637S
Typ
Parameter
Min
Typ
Max
Min
Typ
Max
Min
Max
1
Unit
OUTPUT CHARACTERISTICS
Offset Voltage
1
0.5
mV
mV/°C
V
vs. Temperature
±0.05
0.089
±0.04
0.056
±0.04
0.07
Voltage Swing,
0 to 12.0 13.5
0 to 12.0 13.5
0 to 12.0 13.5
±15 V Supply, 2 kΩ Load
Voltage Swing,
±3 V Supply, 2 kΩ Load
0 to 2
6
2.2
0 to 2
6
2.2
0 to 2
6
2.2
V
Output Current
mA
mA
Ω
Short-Circuit Current
20
20
20
Resistance
0.5
0.5
0.5
Chip Select High
Resistance
100
100
100
kΩ
Chip Select Low
dB OUTPUT
Error, VIN 7 mV to 7 V rms,
0 dB = 1 V rms
±0.5
±0.3
±0.5
dB
Scale Factor
−3
−3
−3
mV/dB
Scale Factor Temperature
Coefficient
+0.33
+0.33
+0.33
± of
reading/°C
−0.033
20
−0.033
20
−0.033
20
dB/°C
μA
IREF for 0 dB = 1 V rms
IREF Range
5
1
80
100
5
1
80
100
5
1
80
100
μA
BUFFER AMPLIFIER
Input Output
−VS to (+VS − 2.5 V)
−VS to (+VS − 2.5 V)
−VS to (+VS − 2.5 V)
V
Voltage Range
Input Offset Voltage
Input Current
±0.8
2
±0.5
1
5
±0.8
±2
mV
nA
±2
108
10
±2
108
±2
108
±10
Input Resistance
Output Current
Short-Circuit Current
Small Signal Bandwidth
Slew Rateꢀ
Ω
−0.13
+5
−0.13
+5
−0.13
+5
mA
mA
MHz
V/μs
20
1
20
1
20
1
5
5
5
DENOMINATOR INPUT
Input Range
0 to 10
0 to 10
0 to 10
V
Input Resistance
Offset Voltage
20
25
30
20
25
30
20
25
30
kΩ
mV
±0.2
±0.5
±0.2
±0.5
±0.2
±0.5
CHIP SELECT (CS)
RMS On Level
Open or 2.4 V < VC < +VS
Open or 2.4 V < VC < +VS
VC < 0.2 V
Open or 2.4 V < VC < +VS
RMS Off Level
VC < 0.2 V
VC < 0.2 V
IOUT of Chip Select
CS Low
10
0
10
0
10
0
μA
μA
μs
CS High
On Time Constant
Off Time Constant
POWER SUPPLY
Operating Voltage Range
Quiescent Current
Standby Current
10 + ((25 kΩ) × CAV
10 + ((25 kΩ) × CAV
)
)
10 + ((25 kΩ) × CAV
10 + ((25 kΩ) × CAV
)
)
10 + ((25 kΩ) × CAV
10 + ((25 kΩ) × CAV
)
)
μs
3.0
18
3.0
18
3.0
18
V
2.2
3
2.2
3
2.2
3
mA
μA
350
450
350
450
350
450
1 Specifications shown in bold are tested on all production units at final electrical test. Results from those tests are used to calculate outgoing quality levels.
All minimum and maximum specifications are guaranteed, although only those shown in boldface are tested on all production units.
2 Accuracy specified 0 V rms to 7 V rms dc with ADꢀ37 connected, as shown in Figure 5.
3 Nonlinearity is defined as the maximum deviation from the straight line connecting the readings at 10 mV and 2 V.
4 Error vs. crest factor is specified as additional error for 1 V rms.
5 Input voltages are expressed in volts rms. Percent is in ± of reading.
ꢀ With external 2 kΩ pull-down resistor tied to −VS.
Rev. K | Page 4 of 20
AD637
ABSOLUTE MAXIMUM RATINGS
Stresses above those listed under Absolute Maximum Ratings
Table 2.
Parameter
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.
Rating
ESD Rating
Supply Voltage
500 V
±18 V dc
108 mW
Indefinite
−ꢀ5°C to +150°C
300°C
Internal Quiescent Power Dissipation
Output Short-Circuit Duration
Storage Temperature Range
Lead Temperature (Soldering 10 sec)
Rated Operating Temperature Range
ADꢀ37J, ADꢀ37K
ESD CAUTION
0°C to 70°C
ADꢀ37A, ADꢀ37B
ADꢀ37S, 59ꢀ2-89ꢀ3701CA
−40°C to +85°C
−55°C to +125°C
Rev. K | Page 5 of 20
AD637
PIN CONFIGURATIONS AND FUNCTION DESCRIPTIONS
BUFF IN
NC
1
2
3
4
5
6
7
14 BUFF OUT
13
BUFF IN
NC
1
2
3
4
5
6
7
8
16 BUFF OUT
V
15
14
V
IN
IN
COMMON
OUTPUT OFFSET
CS
12 NC
11 +V
COMMON
OUTPUT OFFSET
CS
NC
AD637
AD637
TOP VIEW
13 +V
12 –V
S
S
S
TOP VIEW
(Not to Scale)
(Not to Scale)
10 –V
S
DEN INPUT
dB OUTPUT
9
8
RMS OUT
DEN INPUT
dB OUTPUT
NC
11 RMS OUT
C
10
9
C
AV
AV
NC
NC = NO CONNECT
NC = NO CONNECT
Figure 2. 14-Lead SBDIP/CERDIP Pin Configuration
Figure 3. 16-Lead SOIC_W Pin Configuration
Table 3. 14-Lead SBDIP/CERDIP Pin Function Descriptions
Table 4. 16-Lead SOIC_W Pin Function Descriptions
Pin No. Mnemonic
Description
Pin No.
Mnemonic
Description
1
2, 12
3
BUFF IN
NC
COMMON
Buffer Input
No Connection
Analog Common
1
BUFF IN
Buffer Input
No Connection
Analog Common
2, 8, 9, 14 NC
3
COMMON
4
OUTPUT OFFSET Output Offset
4
OUTPUT OFFSET Output Offset
5
CS
Chip Select
5
CS
Chip Select
ꢀ
7
8
9
10
11
13
14
DEN INPUT
dB OUTPUT
CAV
RMS OUT
−VS
+VS
VIN
BUFF OUT
Denominator Input
dB Output
Averaging Capacitor Connection
RMS Output
Negative Supply Rail
Positive Supply Rail
Signal Input
ꢀ
7
DEN INPUT
dB OUTPUT
CAV
RMS OUT
−VS
+VS
VIN
BUFF OUT
Denominator Input
dB Output
Averaging Capacitor Connection
RMS Output
Negative Supply Rail
Positive Supply Rail
Signal Input
10
11
12
13
15
1ꢀ
Buffer Output
Buffer Output
Rev. K | Page ꢀ of 20
AD637
FUNCTIONAL DESCRIPTION
FILTER/AMPLIFIER
8
11
9
C
AV
14
BUFF OUT
ONE QUADRANT
SQUARER/DIVIDER
24kΩ
+V
S
1
BUFF IN
BUFFER
AMPLIFIER
A5
RMS
OUT
A4
I
4
dB
7
3
I
OUTPUT
1
24kΩ
COMMON
Q4
Q1
ABSOLUTE VALUE VOLTAGE TO
CURRENT CONVERTER
5
6
4
CS
Q5
BIAS
DEN
INPUT
I
3
24kΩ
Q2
Q3
A3
6kΩ
6kΩ
OUTPUT
OFFSET
A2
12kΩ
125Ω
AD637
V
13
IN
A1
10 –V
S
Figure 4. Simplified Schematic
The AD637 embodies an implicit solution of the rms equation
that overcomes the inherent limitations of straightforward rms
computation. The actual computation performed by the AD637
follows the equation
To compute the absolute value of the input signal, the averaging
capacitor is omitted. However, a small capacitance value at the
averaging capacitor pin is recommended to maintain stability;
5 pF is sufficient for this purpose. The circuit operates identically
to that of the rms configuration, except that I3 is now equal to
I4, giving
2
⎡
⎢
⎤
⎥
VIN
V rms = Avg
V rms
⎢
⎥
⎣
⎦
2
I1
I4 =
I4
Figure 4 is a simplified schematic of the AD637, subdivided
into four major sections: absolute value circuit (active rectifier),
squarer/divider, filter circuit, and buffer amplifier. The input
voltage (VIN), which can be ac or dc, is converted to a unipolar
current I1 by the active rectifiers A1 and A2. I1 drives one input
of the squarer/divider, which has the transfer function
I4 = |I1|
The denominator current can also be supplied externally by
providing a reference voltage (VREF) to Pin 6. The circuit operates
identically to the rms case, except that I3 is now proportional to
VREF. Therefore,
2
I1
2
I4 =
I1
I3
I4 = Avg
I3
The output current of the squarer/divider I4 drives A4, forming
a low-pass filter with the external averaging capacitor. If the RC
time constant of the filter is much greater than the longest period
of the input signal, then the A4 output is proportional to the
average of I4. The output of this filter amplifier is used by A3
to provide the denominator current I3, which equals Avg I4 and
is returned to the squarer/divider to complete the implicit rms
computation
and
2
VIN
VOUT
=
VDEN
This is the mean square of the input signal.
2
⎡
⎢
⎣
⎤
⎥
⎦
I1
I4
I4 = Avg
= I1 rms
and
V
OUT = VIN rms
Rev. K | Page 7 of 20
AD637
20
15
10
5
STANDARD CONNECTION
The AD637 is simple to connect for a majority of rms
measurements. In the standard rms connection shown in Figure 5,
only a single external capacitor is required to set the averaging
time constant. In this configuration, the AD637 computes the
true rms of any input signal. An averaging error, the magnitude
of which is dependent on the value of the averaging capacitor,
is present at low frequencies. For example, if the filter capacitor,
C
AV, is 4 μF, the error is 0.1% at 10 Hz and increases to 1% at
3 Hz. To measure ac signals, the AD637 can be ac-coupled by
adding a nonpolar capacitor in series with the input, as shown
in Figure 5.
0
0
±3
±5
±10
±15
±18
SUPPLY VOLTAGE – DUAL SUPPLY (V)
AD637
1
BUFF IN
BUFF
OUT 14
NC
Figure 6. Maximum VOUT vs. Supply Voltage
2
3
NC
V
IN
V
CHIP SELECT
IN
13
ABSOLUTE
VALUE
The AD637 includes a chip select feature that allows the user
to decrease the quiescent current of the device from 2.2 mA to
350 μA. This is done by driving CS, Pin 5, to below 0.2 V dc.
Under these conditions, the output goes into a high impedance
state. In addition to reducing the power consumption,
the outputs of multiple devices can be connected in parallel
to form a wide bandwidth rms multiplexer. Tie Pin 5 high to
disable the chip select.
COMMON
NC 12
11
+V
S
(OPTIONAL)
SQUARER/
DIVIDER
OUTPUT
OFFSET
4
5
6
7
+V
BIAS
+V
S
S
4.7kΩ
CS
10
9
–V
C
–V
S
S
25kΩ
DEN
INPUT
2
= V
IN
V
OUT
25kΩ
C
+
8
AV
dB OUTPUT
AV
OPTIONAL TRIMS FOR HIGH ACCURACY
The AD637 includes provisions for trimming out output offset
and scale factor errors resulting in significant reduction in the
maximum total error, as shown in Figure 7. The residual error is
due to a nontrimmable input offset in the absolute value circuit
and the irreducible nonlinearity of the device.
Figure 5. Standard RMS Connection
The performance of the AD637 is tolerant of minor variations
in the power supply voltages; however, if the supplies used
exhibit a considerable amount of high frequency ripple, it is
advisable to bypass both supplies to ground through a 0.1 μF
Referring to Figure 8, the trimming process is as follows:
ceramic disc capacitor placed as close to the device as possible.
• Offset trim: Ground the input signal (VIN) and adjust R1 to
give 0 V output from Pin 9. Alternatively, R1 can be adjusted
to give the correct output with the lowest expected value of VIN.
The output signal range of the AD637 is a function of the
supply voltages, as shown in Figure 6. The output signal can be
used buffered or nonbuffered, depending on the characteristics
of the load. If no buffer is needed, tie the buffer input (Pin 1) to
common. The output of the AD637 is capable of driving 5 mA
into a 2 kΩ load without degrading the accuracy of the device.
• Scale factor trim: Resistor R4 is inserted in series with the
input to lower the range of the scale factor. Connect the
desired full-scale input to VIN, using either a dc or a calibrated ac
signal, and trim Resistor R3 to give the correct output at Pin 9
(that is, 1 V dc at the input results in a dc output voltage of
l.000 V dc). A 2 V p-p sine wave input yields 0.707 V dc at the
output. Remaining errors are due to the nonlinearity.
Rev. K | Page 8 of 20
AD637
5.0
2.5
E
O
IDEAL
O
E
AD637K MAX
DC ERROR = AVERAGE OF OUTPUT – IDEAL
INTERNAL TRIM
AD637K
AVERAGE ERROR
DOUBLE-FREQUENCY
RIPPLE
0
EXTERNAL TRIM
TIME
Figure 9. Typical Output Waveform for a Sinusoidal Input
–2.5
–5.0
AD637K: 0.5mV ± 0.2%
This ripple can add a significant amount of uncertainty to the
accuracy of the measurement being made. The uncertainty can
be significantly reduced through the use of a postfiltering
network or by increasing the value of the averaging capacitor.
0.25mV ± 0.05%
EXTERNAL
0
0.5
1.0
INPUT LEVEL (V)
1.5
2.0
Figure 7. Maximum Total Error vs.
Input Level AD637K Internal and External Trims
The dc error appears as a frequency dependent offset at the
output of the AD637 and follows the relationship
AD637
1
BUFF IN
BUFF
OUT 14
NC
1
in% of reading
0.16 + 6.4 τ2 f 2
R4
2
3
NC
V
147Ω
IN
V
IN
13
ABSOLUTE
VALUE
OUTPUT
OFFSET
TRIM
COMMON
Because the averaging time constant, set by CAV, directly sets
the time that the rms converter holds the input signal during
computation, the magnitude of the dc error is determined only
by CAV and is not affected by postfiltering.
NC 12
11
+V
S
SQUARER/
DIVIDER
R2
OUTPUT
OFFSET
1MΩ
4
5
6
7
R1
50kΩ
+V
BIAS
+V
S
S
4.7kΩ
–V
CS
10
9
S
+V
–V
–V
S
S
S
25kΩ
DEN
INPUT
2
= V
IN
V
OUT
100
25kΩ
C
+
8
AV
C
dB OUTPUT
AV
SCALE FACTOR TRIM
10
R3
1kΩ
PEAK RIPPLE
Figure 8. Optional External Gain and Offset Trims
1.0
CHOOSING THE AVERAGING TIME CONSTANT
DC ERROR
The AD637 computes the true rms value of both dc and ac
input signals. At dc, the output tracks the absolute value of the
input exactly; with ac signals, the AD637 output approaches the
true rms value of the input. The deviation from the ideal rms
value is due to an averaging error. The averaging error
comprises an ac component and a dc component. Both
components are functions of input signal frequency f and the
averaging time constant τ (τ: 25 ms/μF of averaging capacitance).
Figure 9 shows that the averaging error is defined as the peak
0.1
10
100
1k
10k
SINE WAVE INPUT FREQUENCY (Hz)
Figure 10. Comparison of Percent DC Error to the Percent Peak Ripple over
Frequency Using the AD637 in the Standard RMS Connection with a 1 × μF CAV
The ac ripple component of averaging error is greatly reduced
by increasing the value of the averaging capacitor. There are two
major disadvantages to this: the value of the averaging capacitor
becomes extremely large and the settling time of the AD637
increases in direct proportion to the value of the averaging
capacitor (TS = 115 ms/μF of averaging capacitance). A preferable
method of reducing the ripple is by using the postfilter network,
as shown in Figure 11. This network can be used in either a 1-
pole or 2-pole configuration. For most applications, the 1-pole
filter gives the best overall compromise between ripple and
settling time.
value of the ac component (ripple) and the value of the dc error.
The peak value of the ac ripple component of the averaging
error is defined approximately by the relationship
50
6.3 τf
(
)
in % of reading where τ > 1 f
Rev. K | Page 9 of 20
AD637
100
10
100
10
AD637
1
BUFF IN
BUFF
OUT
0.
14 RMS OUT
13
0
1
%
E
RRO
2
3
NC
V
0.
IN
ABSOLUTE
VALUE
1%
V
R
IN
E
RRO
+
1
COMMON
%
C3
NC 12
R
E
RRO
SQUARER/
DIVIDER
OUTPUT
OFFSET
10
%
R
4
5
6
7
11
10
9
1.0
1.0
0.1
0.01
+V
S
BIAS
+V
–V
ER
S
R
OR
+V
S
4.7kΩ
CS
–V
S
S
25kΩ
DEN
INPUT
0.1
25kΩ
C
+
8
AV
C
dB OUTPUT
AV
*%dc ERROR + %RIPPLE (PEAK)
0.01
1
10
100
1k
10k
100k
INPUT FREQUENCY (Hz)
RX
24kΩ
24kΩ
Figure 12. Values for CAV and 1% Settling Time for Stated % of Reading Averaging
Error* Accuracy Includes 2% Component Tolerance (see * in Figure)
+
C2
FOR A SINGLE-POLE
FILTER SHORT RX
AND REMOVE C3
100
100
10
1
*%dc ERROR + %RIPPLE (PEAK)
ACCURACY ±20% DUE TO
COMPONENT TOLERANCE
Figure 11. 2-Pole Sallen-Key Filter
Figure 12 shows values of CAV and the corresponding averaging
error as a function of sine wave frequency for the standard rms
connection. The 1% settling time is shown on the right side of
Figure 12.
10
0
.
0
1
%
0
1
.
1
E
%
R
R
1
E
%
O
R
Figure 13 shows the relationship between the averaging error,
signal frequency settling time, and averaging capacitor value.
Figure 13 is drawn for filter capacitor values of 3.3× the
averaging capacitor value. This ratio sets the magnitude of the
ac and dc errors equal at 50 Hz. As an example, by using a 1 μF
averaging capacitor and a 3.3 μF filter capacitor, the ripple for
a 60 Hz input signal is reduced from 5.3% of the reading using
the averaging capacitor alone to 0.15% using the 1-pole filter.
This gives a factor of 30 reduction in ripple, and yet the settling
time only increases by a factor of 3. The values of filter
Capacitor CAV and Filter Capacitor C2 can be calculated for
the desired value of averaging error and settling time by using
Figure 13.
R
R
E
5
O
R
%
R
R
E
O
R
R
R
O
0.1
0.01
0.1
R
0.01
100k
1
10
100
1k
10k
INPUT FREQUENCY (Hz)
Figure 13. Values of CAV, C2, and 1% Settling Time for Stated % of Reading
Averaging Error* for 1-Pole Post Filter (see * in Figure)
100
100
10
10
The symmetry of the input signal also has an effect on the
magnitude of the averaging error. Table 5 gives the practical
component values for various types of 60 Hz input signals.
These capacitor values can be directly scaled for frequencies
other than 60 Hz—that is, for 30 Hz, these values are doubled,
and for 120 Hz they are halved.
0
.
0
1%
1
1
0
.1
E
%
RRO
1%
ER
E
R
R
R
ER
RO
5
O
%
R
R
R
0.1
0.01
0.1
0.01
O
R
*%dc ERROR + %RIPPLE (PEAK)
ACCURACY ±20% DUE TO
COMPONENT TOLERANCE
For applications that are extremely sensitive to ripple, the 2-pole
configuration is suggested. This configuration minimizes capacitor
values and the settling time while maximizing performance.
1
10
100
1k
10k
100k
INPUT FREQUENCY (Hz)
Figure 14. Values of CAV, C2, and C3 and 1% Settling Time for Stated % of
Reading Averaging Error* for 2-Pole Sallen-Key Filter (see * in Figure)
Figure 14 can be used to determine the required value of CAV
C2, and C3 for the desired level of ripple and settling time.
,
Rev. K | Page 10 of 20
AD637
Table 5. Practical Values of CAV and C2 for Various Input Waveforms
Recommended Standard Values for CAV and C2
for 1% Averaging Error @ 60 Hz with T = 16.6 ms
Absolute Value
Circuit Waveform
and Period
1/2T
Input Waveform
and Period
Minimum R × CAV
Time Constant
1% Settling
Time
CAV (μF)
C2 (μF)
T
1/2T
0.47
1.5
181 ms
A
0V
Symmetrical Sine Wave
T
T
T
0.82
2.7
325 ms
B
0V
Sine Wave with dc Offset
T
T
10 (T − T2)
ꢀ.8
5.ꢀ
22
18
2.ꢀ7 sec
2.17 sec
T
2
C
D
T
2
0V
Pulse Train Waveform
T
T
10 (T − 2T2)
T
2
T
2
0V
FREQUENCY RESPONSE
The frequency response of the AD637 at various signal levels is
shown in Figure 15. The dashed lines show the upper frequency
limits for 1%, 10%, and 3 dB of additional error. For example,
note that for 1% additional error with a 2 V rms input, the
highest frequency allowable is 200 kHz. A 200 mV signal can
be measured with 1% error at signal frequencies up to 100 kHz.
10
1
7V RMS INPUT
2V RMS INPUT
1V RMS INPUT
1%
10%
±3dB
100mV RMS INPUT
10mV RMS INPUT
0.1
0.01
To take full advantage of the wide bandwidth of the AD637,
care must be taken in the selection of the input buffer amplifier.
To ensure that the input signal is accurately presented to the
converter, the input buffer must have a −3 dB bandwidth that is
wider than that of the AD637. Note the importance of slew rate
in this application. For example, the minimum slew rate required
for a 1 V rms, 5 MHz, sine wave input signal is 44 V/μs. The user is
cautioned that this is the minimum rising or falling slew rate
and that care must be exercised in the selection of the buffer
amplifier, because some amplifiers exhibit a two-to-one
difference between rising and falling slew rates. The AD845 is
recommended as a precision input buffer.
1k
10k
100k
INPUT FREQUENCY (Hz)
1M
10M
Figure 15. Frequency Response
Rev. K | Page 11 of 20
AD637
1.5
1.0
0.5
AC MEASUREMENT ACCURACY AND CREST
FACTOR
Crest factor is often overlooked in determining the accuracy of
an ac measurement. Crest factor is defined as the ratio of the peak
signal amplitude to the rms value of the signal (CF = VP/V rms).
Most common waveforms, such as sine and triangle waves, have
relatively low crest factors (≤2). Waveforms that resemble low
duty cycle pulse trains, such as those occurring in switching
power supplies and SCR circuits, have high crest factors. For
example, a rectangular pulse train with a 1% duty cycle has
0
–0.5
–1.0
–1.5
POSITIVE INPUT PULSE
= 22µF
C
AV
a crest factor of 10 (CF = 1 η ).
1
2
3
4
5
6
7
8
9
10
11
100µs
T
T
η = DUTY CYCLE =
CF = 1/
(RMS) = 1 V RMS
CREST FACTOR
Vp
e
0
η
Figure 18. Additional Error vs. Crest Factor
0
e
IN
100µs
2.0
1.8
1.6
1.4
1.2
1.0
0.8
0.6
0.4
0.2
0
Figure 16. Duty Cycle Timing
10
C
= 22µF
AV
CF = 10
CF = 7
1
CF = 10
0.1
0.01
CF = 3
0
0.5
1.0
1.5
2.0
CF = 3
V
(V RMS)
IN
Figure 19. Error vs. RMS Input Level for Three Common Crest Factors
1
10
100
1000
PULSE WIDTH (µs)
CONNECTION FOR dB OUTPUT
Figure 17. AD637 Error vs. Pulse Width Rectangular Pulse
Another feature of the AD637 is the logarithmic, or decibel,
output. The internal circuit that computes dB works well over
a 60 dB range. Figure 20 shows the dB measurement connection.
The user selects the 0 dB level by setting R1 for the proper 0 dB
reference current, which is set to cancel the log output current
from the squarer/divider circuit at the desired 0 dB point. The
external op amp is used to provide a more convenient scale and to
allow compensation of the +0.33%/°C temperature drift of the
dB circuit. The temperature resistor R3, as shown in Figure 20,
is available from Precision Resistor Co., Inc., in Largo, Fla.
(Model PT146). Consult its website for additional information.
Figure 18 is a curve of additional reading error for the AD637
for a 1 V rms input signal with crest factors from 1 to 11.
A rectangular pulse train (pulse width 100 μs) is used for this
test because it is the worst-case waveform for rms measurement
(all the energy is contained in the peaks). The duty cycle and
peak amplitude were varied to produce crest factors from l to 10
while maintaining a constant 1 V rms input amplitude.
Rev. K | Page 12 of 20
AD637
dB CALIBRATION
Refer to Figure 20:
• Set VIN = 1.00 V dc or 1.00 V rms
• Adjust R1 for 0 dB out = 0.00 V
• Set VIN = 0.1 V dc or 0.10 V rms
• Adjust R2 for dB out = −2.00 V
Any other dB reference can be used by setting VIN and R1
accordingly.
R2
dB SCALE
FACTOR
ADJUST
33.2kΩ
SIGNAL
INPUT
5kΩ
+V
S
BUFFER
BUFF
OUT 14
R3
1kΩ*
AD637
1
2
3
4
5
6
7
BUFF IN
NC
7
2
60.4Ω
6
AD707JN
V
IN 13
ABSOLUTE
VALUE
3
COMPENSATED
dB OUTPUT
+ 100mV/dB
4
COMMON
NC 12
11
–V
S
BIAS
OUTPUT
OFFSET
SECTION
SQUARER/DIVIDER
+V
+V
–V
S
S
25kΩ
4.7kΩ
CS
10
9
+V
S
–V
S
S
DEN
INPUT
V
25kΩ
OUT
+
1µF
8
dB OUTPUT
FILTER
C
AV
10kΩ
NC = NO CONNECT
+V
S
R1
500kΩ
+2.5 V
AD508J
0dB ADJUST
*1kΩ + 3500ppm
SEE TEXT
Figure 20. dB Connection
Rev. K | Page 13 of 20
AD637
V+
1µF
3.3MΩ 3.3MΩ
7
3
2
1µF
6
AD548JN
BUFFER
BUFF
OUT 14
AD637
FILTERED
V RMS OUTPUT
1
BUFF IN
4
V
IN 13
V–
2
3
NC
SIGNAL
INPUT
ABSOLUTE
VALUE
6.8MΩ
COMMON
NC 12
11
+V
S
BIAS
SECTION
OUTPUT
OFFSET
1000pF
OUTPUT
OFFSET
ADJUST
1MΩ
4
5
SQUARER/DIVIDER
+V
+V
S
50kΩ
S
25kΩ
+V
CS
S
10
–V
–V
S
S
–V
S
4.7kΩ
V
25kΩ
2
OUT
9
V
IN
V RMS
+
6
7
DEN
100µF
INPUT
C
AV
8
FILTER
dB OUTPUT
499kΩ 1%
R
C
AV1
3.3µF
NOTES
1. VALUES CHOSEN TO GIVE 0.1% AVERAGING ERROR @ 1Hz.
2. NC = NO CONNECT.
Figure 21. AD637 as a Low Frequency RMS Converter
LOW FREQUENCY MEASUREMENTS
VECTOR SUMMATION
If the frequencies of the signals to be measured are below 10 Hz,
the value of the averaging capacitor required to deliver even 1%
averaging error in the standard rms connection becomes
extremely large. Figure 21 shows an alternative method of
obtaining low frequency rms measurements. The averaging
time constant is determined by the product of R and CAV1, in
this circuit, 0.5 sec/μF of CAV. This circuit permits a 20:1
reduction in the value of the averaging capacitor, permitting the
use of high quality tantalum capacitors. It is suggested that the
2-pole, Sallen-Key filter shown in Figure 21 be used to obtain a
low ripple level and minimize the value of the averaging
capacitor.
Vector summation can be accomplished through the use of two
AD637s, as shown in Figure 22. Here, the averaging capacitors
are omitted (nominal 100 pF capacitors are used to ensure
stability of the filter amplifier), and the outputs are summed as
shown. The output of the circuit is
2
2
VOUT = VX +VY
This concept can be expanded to include additional terms by
feeding the signal from Pin 9 of each additional AD637 through
a 10 kΩ resistor to the summing junction of the AD711 and
tying all of the denominator inputs (Pin 6) together.
If CAV is added to IC1 in this configuration, then the output is
If the frequency of interest is below 1 Hz, or if the value of the
averaging capacitor is still too large, the 20:1 ratio can be
increased. This is accomplished by increasing the value of R.
If this is done, it is suggested that a low input current, low offset
voltage amplifier, such as the AD548, be used instead of the
internal buffer amplifier. This is necessary to minimize the
offset error introduced by the combination of amplifier input
currents and the larger resistance.
2
2
VX + VY
If the averaging capacitor is included on both IC1 and IC2, the
output is
2
2
VX +VY
This circuit has a dynamic range of 10 V to 10 mV and is
limited only by the 0.5 mV offset voltage of the AD637.
The useful bandwidth is 100 kHz.
Rev. K | Page 14 of 20
AD637
EXPANDABLE
BUFFER
AD637
BUFF
OUT
IC1
BUFF IN
14
13
1
V IN
X
ABSOLUTE
VALUE
2
3
NC
COMMON
NC 12
11
BIAS
OUTPUT
OFFSET
SECTION
4
5
6
SQUARER/DIVIDER
+V
+V
S
S
25kΩ
+V
10
9
S
CS
–V
–V
S
S
4.7kΩ
V
25kΩ
OUT
DEN
INPUT
100pF
5pF
C
FILTER
AV
7
dB OUTPUT
BUFF IN
8
10kΩ
10kΩ
BUFFER
BUFF
OUT
AD637
IC2
1
14
13
V IN
Y
AD711K
2
3
NC
ABSOLUTE
VALUE
COMMON
10kΩ
NC 12
BIAS
OUTPUT
OFFSET
SECTION
11
10
SQUARER/DIVIDER
4
5
6
+V
S
+V
S
20kΩ
25kΩ
+V
S
CS
–V
S
–V
S
4.7kΩ
DEN
INPUT
V
25kΩ
OUT
9
8
100pF
dB OUTPUT
FILTER
7
2 2
+ V
X Y
V
=
V
OUT
Figure 22. Vector Sum Configuration
Rev. K | Page 15 of 20
AD637
EVALUATION BOARD
amp, and is configured on the AD637-EVALZ as a low-pass
Sallen-Key filter whose fC < 0.5 Hz. Users can connect to the
buffer by moving the FILTER switch to the on position.
DC_OUT is still the output of the AD637, and the test loop,
BUF_OUT, is the output of the buffer. The R2 trimmer adjusts
the output offset voltage.
Figure 23 shows a digital image of the AD637-EVALZ, an
evaluation board specially designed for the AD637. It is
available at www.analog.com and is fully tested and ready for
bench testing after connecting power and signal I/O. The circuit
is configured for dual power supplies, and standard BNC
connectors serve as the signal input and output ports.
The LPF frequency is changed by changing the component
values of CF1, CF2, R4, and R5. See Figure 24 and Figure 30 to
locate these components. Note that a wide range of capacitor
and resistor values can be used with the AD637 buffer amplifier.
Referring to the schematic in Figure 30, the input connector
RMS_IN is capacitively coupled to Pin 15 (VIN of SOIC package) of
the AD637. The DC_OUT connector is connected to Pin 11,
RMS OUT, with provisions for connections to the output buffer
between Pin 1 and Pin 16. The buffer is an uncommitted op
Figure 23. AD637-EVALZ
Rev. K | Page 1ꢀ of 20
AD637
Figure 27. Evaluation Board—Secondary Side Copper
Figure 28. Evaluation Board—Internal Power Plane
Figure 29. Evaluation Board—Internal Ground Plane
Figure 24. AD637-EVALZ Assembly
Figure 25. Component Side Silkscreen
Figure 26. Evaluation Board—Component Side Copper
Rev. K | Page 17 of 20
AD637
–V
–V
+V
+V
S
S
S
GND1 GND2 GND3 GND4
C1
C2
10µF
25V
+
10µF
25V
+
S
FILTER
BUF_IN
4
OUT
1
2
5
3
IN
6
1
16
15
BUFF IN
NC
BUFF OUT
BUF_OUT
RMS_IN
RMS_IN
Z1
AD637
2
3
V
IN
CIN
22µF
16V
+V
–V
S
14
13
COMMON
NC
R1
1Mꢀ
4
5
6
7
R2
50kꢀ
OUTPUT
OFFSET
+V
+V
–V
S
S
S
C3
R3
4.7kꢀ
0.1µF
12
11
10
+V
S
CS
–V
S
DC_OUT
C4
0.1µF
S
DC_OUT
DEN INPUT
dB OUTPUT
NC
RMS OUT
+
C
AV
22µF
16V
C
AV
DB_OUT
8
9
NC
+
CF1
47µF
25V
R5
24.3kꢀ
R4
24.3kꢀ
+
CF2
47µF
25V
Figure 30. Evaluation Board Schematic
AC OR DC INPUT SIGNAL SOURCE
FROM PRECISION CALIBRATOR
OR FUNCTION GENERATOR
POWER
SUPPLY
PRECISION DMM TO
MONITOR VOUT
Figure 31. AD637-EVALZ Typical Bench Configuration
Rev. K | Page 18 of 20
AD637
OUTLINE DIMENSIONS
0.005 (0.13) MIN
0.080 (2.03) MAX
8
14
0.310 (7.87)
1
0.220 (5.59)
7
PIN 1
0.100 (2.54)
BSC
0.320 (8.13)
0.290 (7.37)
0.765 (19.43) MAX
0.060 (1.52)
0.015 (0.38)
0.200 (5.08)
MAX
0.150
(3.81)
MIN
0.200 (5.08)
0.125 (3.18)
0.015 (0.38)
0.008 (0.20)
SEATING
PLANE
0.070 (1.78)
0.030 (0.76)
0.023 (0.58)
0.014 (0.36)
CONTROLLING DIMENSIONS ARE IN INCHES; MILLIMETER DIMENSIONS
(IN PARENTHESES) ARE ROUNDED-OFF INCH EQUIVALENTS FOR
REFERENCE ONLY AND ARE NOT APPROPRIATE FOR USE IN DESIGN.
Figure 32. 14-Lead Side-Brazed Ceramic Dual In-Line Package [SBDIP]
(D-14)
Dimensions shown in inches and (millimeters)
0.098 (2.49) MAX
8
0.005 (0.13) MIN
14
0.310 (7.87)
0.220 (5.59)
1
7
PIN 1
0.100 (2.54) BSC
0.785 (19.94) MAX
0.320 (8.13)
0.290 (7.37)
0.060 (1.52)
0.015 (0.38)
0.200 (5.08)
MAX
0.150
(3.81)
MIN
0.200 (5.08)
0.125 (3.18)
0.015 (0.38)
0.008 (0.20)
SEATING
PLANE
15°
0°
0.070 (1.78)
0.030 (0.76)
0.023 (0.58)
0.014 (0.36)
CONTROLLING DIMENSIONS ARE IN INCHES; MILLIMETER DIMENSIONS
(IN PARENTHESES) ARE ROUNDED-OFF INCH EQUIVALENTS FOR
REFERENCE ONLY AND ARE NOT APPROPRIATE FOR USE IN DESIGN.
Figure 33. 14-Lead Ceramic Dual In-Line Package [CERDIP]
(Q-14)
Dimensions shown in inches and (millimeters)
Rev. K | Page 19 of 20
AD637
10.50 (0.4134)
10.10 (0.3976)
16
1
9
8
7.60 (0.2992)
7.40 (0.2913)
10.65 (0.4193)
10.00 (0.3937)
0.75 (0.0295)
0.25 (0.0098)
1.27 (0.0500)
BSC
45°
2.65 (0.1043)
2.35 (0.0925)
0.30 (0.0118)
0.10 (0.0039)
8°
0°
COPLANARITY
0.10
SEATING
PLANE
0.51 (0.0201)
0.31 (0.0122)
1.27 (0.0500)
0.40 (0.0157)
0.33 (0.0130)
0.20 (0.0079)
COMPLIANT TO JEDEC STANDARDS MS-013-AA
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 34. 16-Lead Standard Small Outline Package [SOIC_W]
Wide Body (RW-16)
Dimensions shown in millimeters and (inches)
ORDERING GUIDE
Model1
59ꢀ2-89ꢀ3701CA
ADꢀ37AQ
ADꢀ37AR
ADꢀ37ARZ
ADꢀ37BQ
ADꢀ37BR
ADꢀ37BRZ
ADꢀ37JD
Notes
2
Temperature Range
−55°C to +125°C
−40°C to +85°C
−40°C to +85°C
−40°C to +85°C
−40°C to +85°C
−40°C to +85°C
−40°C to +85°C
0°C to 70°C
Package Description
14-Lead CERDIP
14-Lead CERDIP
1ꢀ-Lead SOIC_W
1ꢀ-Lead SOIC_W
14-Lead CERDIP
1ꢀ-Lead SOIC_W
1ꢀ-Lead SOIC_W
14-Lead SBDIP
Package Option
Q-14
Q-14
RW-1ꢀ
RW-1ꢀ
Q-14
RW-1ꢀ
RW-1ꢀ
D-14
ADꢀ37JDZ
0°C to 70°C
14-Lead SBDIP
D-14
ADꢀ37JQ
ADꢀ37JR
0°C to 70°C
0°C to 70°C
0°C to 70°C
0°C to 70°C
0°C to 70°C
0°C to 70°C
0°C to 70°C
0°C to 70°C
14-Lead CERDIP
1ꢀ-Lead SOIC_W
1ꢀ-Lead SOIC_W
1ꢀ-Lead SOIC_W
1ꢀ-Lead SOIC_W
1ꢀ-Lead SOIC_W
1ꢀ-Lead SOIC_W
14-Lead SBDIP
Q-14
RW-1ꢀ
RW-1ꢀ
RW-1ꢀ
RW-1ꢀ
RW-1ꢀ
RW-1ꢀ
D-14
ADꢀ37JR-REEL
ADꢀ37JR-REEL7
ADꢀ37JRZ
ADꢀ37JRZ-RL
ADꢀ37JRZ-R7
ADꢀ37KD
ADꢀ37KDZ
ADꢀ37KQ
ADꢀ37KRZ
0°C to 70°C
0°C to 70°C
0°C to 70°C
−55°C to +125°C
−55°C to +125°C
−55°C to +125°C
14-Lead SBDIP
D-14
Q-14
RW-1ꢀ
D-14
D-14
14-Lead CERDIP
1ꢀ-Lead SOIC_W
14-Lead SBDIP
14-Lead SBDIP
14-Lead CERDIP
Evaluation Board
ADꢀ37SD
ADꢀ37SD/883B
ADꢀ37SQ/883B
ADꢀ37-EVALZ
Q-14
1 Z = RoHS Compliant Part.
2 A standard microcircuit drawing is available.
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D00788-0-2/11(K)
Rev. K | Page 20 of 20
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