AD737KRZ [ADI]
暂无描述;
| 型号： | AD737KRZ |
| 厂家： | 
ADI |
| 描述： | 暂无描述 |
| 文件： | 总24页 (文件大小：493K) |
| 中文： | 中文翻译 | 下载： | 下载PDF数据表文档文件 |
Low Cost, Low Power,
True RMS-to-DC Converter
Data Sheet
AD737
FEATURES
Computes
FUNCTIONAL BLOCK DIAGRAM
COM
8kΩ
8kΩ
C
True rms value
C
C
F
Average rectified value
Absolute value
Provides
ABSOLUTE
VALUE
CIRCUIT
OUTPUT
SQUARER
DIVIDER
V
IN
200 mV full-scale input range (larger inputs with
input scaling)
C
AV
+V
C
S
AV
BIAS
SECTION
Direct interfacing with 3½ digit CMOS ADCs
POWER
DOWN
–V
S
High input impedance: 1012
Ω
Low input bias current: 25 pA maximum
High accuracy: 0.2 mV 0.3% of reading
Figure 1.
RMS conversion with signal crest factors up to 5
Wide power supply range: 2.5 V to 16.5 V
Low power: 25 µA (typical) standby current
No external trims needed for specified accuracy
The AD737 output is negative-going; the AD736 is a positive
output-going version of the same basic device
GENERAL DESCRIPTION
The AD737 is a low power, precision, monolithic, true rms-to-
dc converter. It is laser trimmed to provide a maximum error of
0.2 mV 0.3% of reading with sine wave inputs. Furthermore,
it maintains high accuracy while measuring a wide range of
input waveforms, including variable duty cycle pulses and
triac (phase) controlled sine waves. The low cost and small
physical size of this converter make it suitable for upgrading
the performance of non-rms precision rectifiers in many
applications. Compared to these circuits, the AD737 offers
higher accuracy at equal or lower cost.
The AD737 has both high (1012 Ω) and low impedance input
options. The high-Z FET input connects high source impedance
input attenuators, and a low impedance (8 kΩ) input accepts
rms voltages to 0.9 V while operating from the minimum power
supply voltage of 2.5 V. The two inputs can be used either
single ended or differentially.
The AD737 achieves 1% of reading error bandwidth, exceeding
10 kHz for input amplitudes from 20 mV rms to 200 mV rms,
while consuming only 0.72 mW.
The AD737 is available in two performance grades. The AD737J
and AD737K grades operate over the commercial temperature
range of 0°C to 70°C. The AD737JR-5 is tested with supply
voltages of 2.5 V dc. The AD737A grade operates over the
industrial temperature range of −40°C to +85°C. The AD737 is
available in two low cost, 8lead packages: PDIP and SOIC_N.
The AD737 can compute the rms value of both ac and dc input
voltages. It can also be operated ac-coupled by adding one
external capacitor. In this mode, the AD737 can resolve input
signal levels of 100 µV rms or less, despite variations in tem-
perature or supply voltage. High accuracy is also maintained for
input waveforms with crest factors of 1 to 3. In addition, crest
factors as high as 5 can be measured (while introducing only
2.5% additional error) at the 200 mV full-scale input level.
PRODUCT HIGHLIGHTS
1. Computes average rectified, absolute, or true rms value of a
signal regardless of waveform.
2. Only one external component, an averaging capacitor, is
required for the AD737 to perform true rms measurement.
3. The standby power consumption of 125 μW makes the
AD737 suitable for battery-powered applications.
The AD737 has no output buffer amplifier, thereby significantly
reducing dc offset errors occurring at the output, which makes
the device highly compatible with high input impedance ADCs.
Requiring only 160 µA of power supply current, the AD737 is
optimized for use in portable multimeters and other battery-
powered applications. In power-down mode, the standby supply
current in is typically 25 µA.
Rev. I
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
rightsof third parties that may result fromits 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 andregisteredtrademarks 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
Fax: 781.461.3113
www.analog.com
©2012 Analog Devices, Inc. All rights reserved.
AD737
Data Sheet
TABLE OF CONTENTS
Features .............................................................................................. 1
DC Error, Output Ripple, and Averaging Error..................... 13
AC Measurement Accuracy and Crest Factor........................ 13
Calculating Settling Time.......................................................... 13
Applications Information.............................................................. 14
RMS Measurement—Choosing an Optimum Value for CAV ...14
Functional Block Diagram .............................................................. 1
General Description......................................................................... 1
Product Highlights ........................................................................... 1
Revision History ............................................................................... 2
Specifications..................................................................................... 3
Absolute Maximum Ratings............................................................ 6
Thermal Resistance ...................................................................... 6
ESD Caution.................................................................................. 6
Pin Configurations and Function Descriptions ........................... 7
Typical Performance Characteristics ............................................. 8
Theory of Operation ...................................................................... 12
Types of AC Measurement........................................................ 12
Rapid Settling Times via the Average Responding
Connection.................................................................................. 14
Selecting Practical Values for Capacitors................................ 14
Scaling Input and Output Voltages .......................................... 14
AD737 Evaluation Board............................................................... 18
Outline Dimensions....................................................................... 20
Ordering Guide .......................................................................... 21
REVISION HISTORY
Changes to Ordering Guide.......................................................... 21
6/12—Rev. H to Rev. I
Removed CERDIP Package Throughout ........................Universal
Changes to Features, General Description, Product Highlights
Sections and Figure 1 ....................................................................... 1
Changes to Table 1............................................................................ 3
Changes to Table 2............................................................................ 6
Deleted Figure 3, Renumbered Sequentially................................. 7
Changes to Figure 5, Figure 7, and Figure 8 Captions................. 8
Changes to Figure 12 Caption......................................................... 9
Changes to Figure 19 Caption....................................................... 10
Changes to Figure 23...................................................................... 12
Changes to Figure 26...................................................................... 14
Changes to Scaling the Output Voltage Section......................... 15
Changes to Figure 27...................................................................... 16
Deleted Table 7................................................................................ 19
Updated Outline Dimensions....................................................... 20
Changes to Ordering Guide .......................................................... 21
1/05—Rev. E to Rev. F
Updated Format..................................................................Universal
Added Functional Block Diagram ..................................................1
Changes to General Description Section .......................................1
Changes to Pin Configurations and Function
Descriptions Section .........................................................................6
Changes to Typical Performance Characteristics Section ...........7
Changes to Table 4.......................................................................... 11
Change to Figure 24 ....................................................................... 12
Change to Figure 27 ....................................................................... 15
Changes to Ordering Guide.......................................................... 18
6/03—Rev. D to Rev. E
Added AD737JR-5..............................................................Universal
Changes to Features ..........................................................................1
Changes to General Description .....................................................1
Changes to Specifications.................................................................2
Changes to Absolute Maximum Ratings........................................4
Changes to Ordering Guide.............................................................4
Added TPCs 16 through 19 .............................................................6
Changes to Figures 1 and 2 ..............................................................8
Changes to Figure 8........................................................................ 11
Updated Outline Dimensions....................................................... 12
10/08—Rev. G to Rev. H
Added Selectable Average or RMS Conversion Section and
Figure 27 .......................................................................................... 14
Updated Outline Dimensions....................................................... 20
Changes to Ordering Guide .......................................................... 22
12/06—Rev. F to Rev. G
Changes to Specifications................................................................ 3
Reorganized Typical Performance Characteristics ...................... 8
Changes to Figure 21...................................................................... 11
Reorganized Theory of Operation Section ................................. 12
Reorganized Applications Section................................................ 14
Added Scaling Input and Output Voltages Section.................... 14
Deleted Application Circuits Heading......................................... 16
Changes to Figure 28...................................................................... 16
Added AD737 Evaluation Board Section.................................... 18
Updated Outline Dimensions....................................................... 20
12/02—Rev. C to Rev. D
Changes to Functional Block Diagram...........................................1
Changes to Pin Configuration.........................................................4
Figure 1 Replaced ..............................................................................8
Changes to Figure 2...........................................................................8
Figure 5 Replaced ........................................................................... 10
Changes to Application Circuits Figures 4, 6–8 ......................... 10
Outline Dimensions Updated....................................................... 12
12/99—Rev. B to Rev. C
Rev. I | Page 2 of 24
Data Sheet
AD737
SPECIFICATIONS
TA = 25°C, VS = 5 V except as noted, CAV = 33 µF, CC = 10 µF, f = 1 kHz, sine wave input applied to Pin 2, unless otherwise specified.
Specifications shown in boldface are tested on all production units at final electrical test. Results from these tests are used to calculate
outgoing quality levels.
Table 1.
AD737A, AD737J
AD737K
Typ
AD737J-5
Typ
Test Conditions/
Comments
Parameter
ACCURACY
Total Error
Min
Typ
Max
Min
Max
Min
Max
Unit
mV/ POR1
EIN = 0 to 200 mV rms
VS = 2.5 V
0.2/0.3
0.4/0.5
2.0
0.2/0.2
0.2/0.3
mV/ POR1
mV/ POR1
0.2/0.3
0.2/0.3
0.4/0.5
0.4/0.5
VS = 2.5 V,
input to Pin 1
EIN = 200 mV to 1 V rms
−1.2
−1.2
2.0
POR
Over
Temperature
JN, JR, KR
EIN = 200 mV rms,
VS = 2.5 V
EIN = 200 mV rms,
VS = 2.5 V
0.007
0.014
0.007
0.014
0.02
POR/°C
POR/°C
AN and AR
vs. Supply Voltage
E
E
IN = 200 mV rms,
VS = 2.5 V to 5 V
IN = 200 mV rms,
VS = 5 V to 16.5 V
−0.18
0.06
1.3
−0.18
0.06
1.3
−0.18
0.06
%/V
0
0
−0.3
0.1
0
0
−0.3
0.1
0
0
−0.3
0.1
%/V
POR
POR
POR
DC Reversal Error
DC-coupled,
IN = 600 mV dc
2.5
2.5
V
VS = 2.5 V
IN = 200 mV dc
IN = 0 mV to
1.7
2.5
0.1
V
E
Nonlinearity2
Input to Pin 13
0
0.25
0.35
0
0.25
0.35
200 mV rms,
@ 100 mV rms
AC coupled,
0.02
POR
E
IN = 100 mV rms, after
correction, VS = 2.5 V
Total Error,
External Trim
EIN = 0 mV to
200 mV rms
0.1/0.2
0.7
0.1/0.2
0.7
0.1/0.2
mV/ POR
ADDITIONAL
CREST FACTOR
ERROR4
For Crest Factors
from 1 to 3
CAV = CF = 100 µF
%
%
C
AV = 22 µF, CF = 100 µF,
VS = 2.5 V, input to
Pin 1
1.7
For Crest Factors CAV = CF = 100 µF
from 3 to 5
2.5
2.5
%
INPUT
CHARACTERISTICS
High-Z Input (Pin 2)
Signal Range
Continuous
RMS Level
VS = +2.5 V
mV rms
200
VS = +2.8 V/−3.2 V
200
1
200
1
mV rms
V rms
VS = 5 V to 16.5 V
Rev. I | Page 3 of 24
AD737
Data Sheet
AD737A, AD737J
AD737K
Typ
AD737J-5
Typ
Test Conditions/
Comments
Parameter
Min
Typ
Max
Min
Max
Min
0.6
Max
Unit
Peak Transient
VS = +2.5 V input to
Pin 1
V
Input
VS = +2.8 V/−3.2 V
VS = 5 V
VS = 16.5 V
0.9
4.0
0.9
V
2.7
2.7
25
V
V
4.0
1012
1
Input Resistance
Input Bias
Current
Low-Z Input
(Pin 1) Signal
Range
1012
1
1012
1
Ω
pA
VS = 5 V
25
25
Continuous
RMS Level
VS = +2.5 V
300
mV rms
VS = +2.8 V/−3.2 V
VS = 5 V to 16.5 V
VS = +2.5 V
300
1
300
1
mV rms
V rms
V
Peak Transient
Input
1.7
VS = +2.8 V/−3.2 V
VS = 5 V
VS = 16.5 V
1.7
3.8
11
1.7
3.8
11
V
V
V
Input Resistance
6.4
8
9.6
12
6.4
8
9.6
12
6.4
8
9.6
12
kΩ
V p-p
Maximum
Continuous
Nondestructive
Input
Input Offset
Voltage5
All supply voltages
AC-coupled
3
3
3
mV
Over the Rated
Operating
Temperature
Range
8
30
8
30
8
30
µV/°C
vs. Supply
VS = 2.5 V to 5 V
VS = 5 V to 16.5 V
No load, output is
80
50
80
50
80
µV/V
µV/V
150
150
OUTPUT
CHARACTERISTICS negative with respect
to COM
Output Voltage
Range
VS = +2.8 V/−3.2 V
−1.6
−1.7
−1.6
−1.7
V6
V6
V
VS = 5 V
−3.3
−3.4
−3.3
−3.4
VS = 16.5 V
−4
−5
−4
−5
V6
VS = 2.5 V, input to
Pin 1
−1.1
6.4
–0.9
8
Output
Resistance
DC
6.4
8
9.6
6.4
8
9.6
9.6
kΩ
FREQUENCY
RESPONSE
High-Z Input
(Pin 2)
1% Additional
Error
VIN = 1 mV rms
1
1
1
kHz
VIN = 10 mV rms
VIN = 100 mV rms
VIN = 200 mV rms
6
37
33
6
37
33
6
37
33
kHz
kHz
kHz
Rev. I | Page 4 of 24
Data Sheet
AD737
AD737A, AD737J
AD737K
Typ
5
AD737J-5
Typ
5
Test Conditions/
Comments
Parameter
Min
Typ
5
Max
Min
Max
Min
Max
Unit
3 dB Bandwidth VIN = 1 mV rms
VIN = 10 mV rms
kHz
kHz
kHz
kHz
55
55
55
VIN = 100 mV rms
VIN = 200 mV rms
170
190
170
190
170
190
Low-Z Input
(Pin 1)
1% Additional
Error
VIN = 1 mV rms
1
6
1
6
1
kHz
VIN = 10 mV rms
VIN = 40 mV rms
VIN = 100 mV rms
VIN = 200 mV rms
6
kHz
kHz
kHz
kHz
kHz
kHz
kHz
kHz
25
90
90
5
55
350
460
90
90
5
55
350
460
90
90
5
55
350
460
3 dB Bandwidth VIN = 1 mV rms
VIN = 10 mV rms
VIN = 100 mV rms
VIN = 200 mV rms
POWER-DOWN
MODE
Disable Voltage
0
0
V
Input Current,
PD Enabled
VPD = VS
11
11
µA
POWER SUPPLY
Operating
Voltage Range
+2.8/
−3.2
5
16.5
160
210
40
+2.8/
−3.2
5
16.5
2.5
5
16.5
V
Current
No input
120
170
25
120
170
25
160
210
40
120
170
25
160
210
40
µA
µA
µA
Rated input
Powered down
1 POR is % of reading.
2 Nonlinearity is defined as the maximum deviation (in percent error) from a straight line connecting the readings at 0 V and at 200 mV rms.
3 After fourth-order error correction using the equation
y = − 0.31009x4− 0.21692x3− 0.06939x2 + 0.99756x + 11.1 × 10−6
where y is the corrected result and x is the device output between 0.01 V and 0.3 V.
4 Crest factor error is specified as the additional error resulting from the specific crest factor, using a 200 mV rms signal as a reference. The crest factor is defined as
VPEAK/V rms.
5 DC offset does not limit ac resolution.
6 Value is measured with respect to COM.
Rev. I | Page 5 of 24
AD737
Data Sheet
ABSOLUTE MAXIMUM RATINGS
THERMAL RESISTANCE
Table 2.
θJA is specified for the worst-case conditions, that is, a device
soldered in a circuit board for surface-mount packages.
Parameter
Rating
16.5 V
Supply Voltage
Internal Power Dissipation
Input Voltage
Pin 1
200 mW
Table 3. Thermal Resistance
Package Type
θJA
Unit
°C/W
°C/W
12 V
VS
Indefinite
+VS and −VS
−65°C to +125°C
300°C
8-Lead PDIP (N-8)
8-Lead SOIC_N (R-8)
165
155
Pin 2 to Pin 8
Output Short-Circuit Duration
Differential Input Voltage
Storage Temperature Range
Lead Temperature, Soldering (60 sec)
ESD Rating
ESD CAUTION
500 V
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.
Rev. I | Page 6 of 24
Data Sheet
AD737
PIN CONFIGURATIONS AND FUNCTION DESCRIPTIONS
C
1
2
3
4
8
7
6
5
COM
+V
C
C
1
2
3
4
8
7
6
5
COM
C
AD737
V
IN
POWER DOWN
–V
S
V
+V
S
AD737
IN
OUTPUT
TOP VIEW
(Not to Scale)
TOP VIEW
POWER DOWN
OUTPUT
(Not to Scale)
C
S
AV
–V
S
C
AV
Figure 2. SOIC_N Pin Configuration (R-8)
Figure 3. PDIP Pin Configuration (N-8)
Table 4. Pin Function Descriptions
Pin No.
Mnemonic
Description
1
2
3
4
5
6
7
8
CC
VIN
Coupling Capacitor for Indirect DC Coupling.
RMS Input.
POWER DOWN Disables the AD737. Low is enabled; high is powered down.
–VS
CAV
OUTPUT
+VS
Negative Power Supply.
Averaging Capacitor.
Output.
Positive Power Supply.
Common.
COM
Rev. I | Page 7 of 24
AD737
Data Sheet
TYPICAL PERFORMANCE CHARACTERISTICS
TA = 25°C, VS = 5 V (except AD737J-5, where VS = 2.5 V), CAV = 33 µF, CC = 10 µF, f = 1 kHz, sine wave input applied to Pin 2,
unless otherwise specified.
0.7
0.5
0.3
0.1
10V
V
= 200mV rms
= 100µF
IN
C
= 22µF, C = 4.7µF, C = 22µF
AV
F
C
C
C
AV
= 22µF
F
1V
100mV
10mV
1% ERROR
0
–0.1
–3dB
1mV
–0.3
–0.5
10% ERROR
100µV
0
2
4
6
8
10
12
14
16
0.1
1
10
100
1000
SUPPLY VOLTAGE (±V)
FREQUENCY (kHz)
Figure 4. Additional Error vs. Supply Voltage
Figure 7. Frequency Response Driving Pin 1; Negative DC Output
16
10V
DC COUPLED
C
= 22µF, C = 4.7µF, C = 22µF
AV
F
C
14
12
1V
100mV
10mV
1mV
10
8
PIN 1
1% ERROR
PIN 2
6
10% ERROR
4
–3dB
2
0
100µV
0
2
4
6
8
10
12
14
16
0.1
1
10
FREQUENCY (kHz)
100
1000
SUPPLY VOLTAGE (±V)
Figure 5. Peak Input Level for 1% Saturation vs. Supply Voltage
Figure 8. Frequency Response Driving Pin 2; Negative DC Output
25
6
3ms BURST OF 1kHz =
3 CYCLES
200mV rms SIGNAL
C
= 10µF
5
4
3
AV
C
= 22µF
C
F
20
15
10
5
C
= 100µF
C
= 33µF
AV
2
1
0
C
= 100µF
AV
C
= 250µF
AV
1
2
3
4
5
0
2
4
6
8
10
12
14
16
18
CREST FACTOR (V
/V rms)
DUAL SUPPLY VOLTAGE (±V)
PEAK
Figure 6. Supply Current (Power-Down Mode) vs. Supply Voltage (Dual)
Figure 9. Additional Error vs. Crest Factor
Rev. I | Page 8 of 24
Data Sheet
AD737
0.8
1.0
0.5
V
C
= 200mV rms
= 100µF
IN
AV
0.6
0.4
0.2
C
= 22µF
F
0
–0.5
–1.0
–1.5
–2.0
–2.5
0
–0.2
–0.4
–0.6
–0.8
C
= 22µF, C = 47µF,
C
= 4.7µF
AV
C
F
–60 –40 –20
0
20
40
60
80
100 120 140
10mV
100mV
INPUT LEVEL (rms)
1V
2V
TEMPERATURE (°C)
Figure 10. Additional Error vs. Temperature
Figure 13. Error vs. RMS Input Level Using Circuit in Figure 29
500
100
V
C
C
= 200mV rms
= 47µF
= 47µF
IN
C
F
400
300
10
200
–0.5%
100
0
–1%
1
10
0
0.2
0.4
0.6
0.8
1.0
100
FREQUENCY (Hz)
1k
RMS INPUT LEVEL (V)
Figure 11. DC Supply Current vs. RMS Input Level
Figure 14. Value of Averaging Capacitor vs. Frequency
for Specified Averaging Error
10mV
1mV
1V
AC-COUPLED
–0.5%
–1%
100mV
10mV
1mV
100µV
10µV
AC-COUPLED
C
= 10µF, C = 47µF,
AV
= 47µF
C
C
F
100
1k
10k
100k
1
10
100
1k
–3dB FREQUENCY (Hz)
FREQUENCY (Hz)
Figure 12. RMS Input Level vs. –3 dB Frequency; Negative DC Output
Figure 15. RMS Input Level vs. Frequency for Specified Averaging Error
Rev. I | Page 9 of 24
AD737
Data Sheet
4.0
3.5
3.0
2.5
10nA
1nA
100pA
10pA
1pA
2.0
1.5
1.0
100fA
0
2
4
6
8
10
12
14
16
–55
–35
–15
5
25
45
65
85
105
125
SUPPLY VOLTAGE (±V)
TEMPERATURE (°C)
Figure 16. Input Bias Current vs. Supply Voltage
Figure 18. Input Bias Current vs. Temperature
1V
100mV
10mV
1mV
10V
V
=±2.5V,
S
C
C
= 22µF
= 0µF
C
C
= 22µF, C = 4.7µF, C = 22µF
F C
AV
F
1V
C
= 10µF
C
= 100µF
100mV
AV
AV
C
= 33µF
AV
10mV
1mV
100µV
100µV
1ms
10ms
100ms
1s
10s
100s
0.1
1
10
FREQUENCY (kHz)
100
1000
SETTLING TIME
Figure 17. RMS Input Level vs. Settling Time for Three Values of CAV
Figure 19. Frequency Response Driving Pin 1; Negative DC Output
Rev. I | Page 10 of 24
Data Sheet
AD737
10V
1.0
V
=±2.5V,
S
C
= 22µF, C = 4.7µF, C = 22µF
AV
F
C
0.5
0
1V
100mV
–0.5
–1.0
–1.5
–2.0
0.5%
10mV
10%
1mV
–3dB
1%
C
C
= 22µF, V = ±2.5V
S
AV
= 47µF, C = 4.7µF
C
F
100µV
–2.5
10mV
0.1
1
10
FREQUENCY (kHz)
100
1000
100mV
INPUT LEVEL (rms)
1V
2V
Figure 20. Error Contours Driving Pin 1
Figure 22. Error vs. RMS Input Level Driving Pin 1
5
4
3
2
1
0
3 CYCLES OF 1kHz
200mV rms
C
10µF
=
AV
V
C
C
= ±2.5V
= 22µF
= 100µF
S
C
F
C
=
AV
22µF
C
=
AV
33µF
C
=
AV
100µF
C
AV
220µF
=
1
2
3
4
5
CREST FACTOR
Figure 21. Additional Error vs. Crest Factor for Various Values of CAV
Rev. I | Page 11 of 24
AD737
Data Sheet
THEORY OF OPERATION
As shown in Figure 23, the AD737 has four functional subsec-
tions: an input amplifier, a full-wave rectifier, an rms core, and a
bias section. The FET input amplifier allows a high impedance,
buffered input at Pin 2 or a low impedance, wide dynamic range
input at Pin 1. The high impedance input, with its low input bias
current, is ideal for use with high impedance input attenuators.
The input signal can be either dc-coupled or ac-coupled to the
input amplifier. Unlike other rms converters, the AD737 permits
both direct and indirect ac coupling of the inputs. AC coupling is
provided by placing a series capacitor between the input signal
and Pin 2 (or Pin 1) for direct coupling and between Pin 1 and
ground (while driving Pin 2) for indirect coupling.
external averaging capacitor, CF. In the rms circuit, this addi-
tional filtering stage reduces any output ripple that was not
removed by the averaging capacitor.
Finally, the bias subsection permits a power-down function.
This reduces the idle current of the AD737 from 160 µA to
30 µA. This feature is selected by connecting Pin 3 to Pin 7 (+VS).
TYPES OF AC MEASUREMENT
The AD737 is capable of measuring ac signals by operating as
either an average responding converter or a true rms-to-dc con-
verter. As its name implies, an average responding converter
computes the average absolute value of an ac (or ac and dc)
voltage or current by full-wave rectifying and low-pass filtering
the input signal; this approximates the average. The resulting
output, a dc average level, is then scaled by adding (or reducing)
gain; this scale factor converts the dc average reading to an rms
equivalent value for the waveform being measured. For example,
the average absolute value of a sine wave voltage is 0.636 that
AC
C
10µF
C =
+
DC
OPTIONAL RETURN PATH
CURRENT
MODE
ABSOLUTE
VALUE
of VPEAK; the corresponding rms value is 0.707 times VPEAK
Therefore, for sine wave voltages, the required scale factor is
1.11 (0.707 divided by 0.636).
.
C
1
2
3
4
8
C
8kΩ
COM
In contrast to measuring the average value, true rms measure-
ment is a universal language among waveforms, allowing the
magnitudes of all types of voltage (or current) waveforms to be
compared to one another and to dc. RMS is a direct measure of
the power or heating value of an ac voltage compared to that of
a dc voltage; an ac signal of 1 V rms produces the same amount
of heat in a resistor as a 1 V dc signal.
V
IN
C
10µF
F
+
(OPTIONAL
LPF)
+V
7
V
S
IN
8kΩ
FET
OP AMP
I
< 10pA
B
POWER
DOWN
BIAS
SECTION
6
OUTPUT
Mathematically, the rms value of a voltage is defined (using a
simplified equation) as
RMS
TRANSLINEAR
CORE
V rms = Avg(V 2 )
–V
S
5
C
AV
This involves squaring the signal, taking the average, and then
obtaining the square root. True rms converters are smart recti-
fiers; they provide an accurate rms reading regardless of the
type of waveform being measured. However, average responding
converters can exhibit very high errors when their input signals
deviate from their precalibrated waveform; the magnitude of
the error depends on the type of waveform being measured. As
an example, if an average responding converter is calibrated to
measure the rms value of sine wave voltages and then is used
to measure either symmetrical square waves or dc voltages,
the converter has a computational error 11% (of reading)
higher than the true rms value (see Table 5).
C
33µF
A
+
+V
POSITIVE SUPPLY
COMMON
S
0.1µF
0.1µF
–V
NEGATIVE SUPPLY
S
Figure 23. AD737 True RMS Circuit (Test Circuit)
The output of the input amplifier drives a full-wave precision
rectifier, which, in turn, drives the rms core. It is the core that
provides the essential rms operations of squaring, averaging,
and square rooting, using an external averaging capacitor, CAV
.
The transfer function for the AD737 is
Without CAV, the rectified input signal passes through the core
unprocessed, as is done with the average responding connection
(see Figure 25). In the average responding mode, averaging is
carried out by an RC post filter consisting of an 8 kΩ internal
scale factor resistor connected between Pin 6 and Pin 8 and an
2
VOUT
=
Avg(VIN
)
Rev. I | Page 12 of 24
Data Sheet
AD737
DC ERROR, OUTPUT RIPPLE, AND
AVERAGING ERROR
AC MEASUREMENT ACCURACY AND
CREST FACTOR
Figure 24 shows the typical output waveform of the AD737 with
a sine wave input voltage applied. As with all real-world devices,
the ideal output of VOUT = VIN is never exactly achieved; instead,
the output contains both a dc and an ac error component.
The crest factor of the input waveform is often overlooked when
determining the accuracy of an ac measurement. Crest factor is
defined as the ratio of the peak signal amplitude to the rms
amplitude (crest factor = VPEAK/V rms). Many common
waveforms, such as sine and triangle waves, have relatively low
crest factors (≥2). Other waveforms, such as low duty cycle
pulse trains and SCR waveforms, have high crest factors. These
types of waveforms require a long averaging time constant to
average out the long time periods between pulses. Figure 9
shows the additional error vs. the crest factor of the AD737 for
various values of CAV.
E
O
IDEAL
E
O
DC ERROR = E – E (IDEAL)
O
O
AVERAGE E = E
O
O
DOUBLE-FREQUENCY
RIPPLE
CALCULATING SETTLING TIME
TIME
Figure 24. Output Waveform for Sine Wave Input Voltage
Figure 17 can be used to closely approximate the time required
for the AD737 to settle when its input level is reduced in ampli-
tude. The net time required for the rms converter to settle is
the difference between two times extracted from the graph:
the initial time minus the final settling time. As an example,
consider the following conditions: a 33 μF averaging capacitor,
an initial rms input level of 100 mV, and a final (reduced) input
level of 1 mV. From Figure 17, the initial settling time (where
the 100 mV line intersects the 33 μF line) is approximately
80 ms. The settling time corresponding to the new or final
input level of 1 mV is approximately 8 seconds. Therefore, the
net time for the circuit to settle to its new value is 8 seconds
minus 80 ms, which is 7.92 seconds.
As shown, the dc error is the difference between the average
of the output signal (when all the ripple in the output has been
removed by external filtering) and the ideal dc output. The dc
error component is, therefore, set solely by the value of the
averaging capacitor used—no amount of post filtering (using a
very large postfiltering capacitor, CF) allows the output voltage
to equal its ideal value. The ac error component, an output
ripple, can be easily removed using a large enough CF.
In most cases, the combined magnitudes of the dc and ac error
components must be considered when selecting appropriate
values for CAV and CF capacitors. This combined error, repre-
senting the maximum uncertainty of the measurement, is termed
the averaging error and is equal to the peak value of the output
ripple plus the dc error. As the input frequency increases, both
error components decrease rapidly. If the input frequency
doubles, the dc error and ripple reduce to one-quarter and
one-half of their original values, respectively, and rapidly
become insignificant.
Note that, because of the inherent smoothness of the decay
characteristic of a capacitor/diode combination, this is the
total settling time to the final value (not the settling time to 1%,
0.1%, and so on, of the final value). Also, this graph provides
the worst-case settling time because the AD737 settles very
quickly with increasing input levels.
Table 5. Error Introduced by an Average Responding Circuit When Measuring Common Waveforms
Type of Waveform
1 V Peak Amplitude
Crest Factor
(VPEAK/V rms)
True RMS
Value (V)
Reading of an Average Responding Circuit
Calibrated to an RMS Sine Wave Value (V)
Error (%)
0
Undistorted Sine Wave
Symmetrical Square Wave
Undistorted Triangle Wave
Gaussian Noise (98% of Peaks <1 V)
Rectangular
1.414
1.00
1.73
3
2
10
0.707
1.00
0.577
0.333
0.5
0.707
1.11
0.555
0.295
0.278
0.011
11.0
−3.8
−11.4
−44
Pulse Train
0.1
−89
SCR Waveforms
50% Duty Cycle
2
0.495
0.212
0.354
0.150
−28
−30
25% Duty Cycle
4.7
Rev. I | Page 13 of 24
AD737
Data Sheet
APPLICATIONS INFORMATION
RMS MEASUREMENT—CHOOSING AN OPTIMUM
VALUE FOR CAV
1
2
3
4
8
7
C
COM
C
AD737
VIN
V
+V
S
+2.5V
RMS
IN
Because the external averaging capacitor, CAV, holds the rec-
tified input signal during rms computation, its value directly
affects the accuracy of the rms measurement, especially at low
frequencies. Furthermore, because the averaging capacitor is
connected across a diode in the rms core, the averaging time
constant (τAV) increases exponentially as the input signal
decreases. It follows that decreasing the input signal decreases
errors due to nonideal averaging but increases the settling time
approaching the decreased rms-computed dc value. Thus,
diminishing input values allow the circuit to perform better
(due to increased averaging) while increasing the waiting time
between measurements. A trade-off must be made between
1MΩ
6
5
OUT
VOUT
DC
–V
C
AV
S
33µF
NTR4501NT1
33µF
ASSUMED TO
BE A LOGIC
SOURCE
rms
AVG
–2.5V
Figure 26. CMOS Switch Is Used to Select RMS or Average Responding Modes
SELECTING PRACTICAL VALUES FOR CAPACITORS
Table 6 provides practical values of CAV and CF for several
common applications.
computational accuracy and settling time when selecting CAV
.
The input coupling capacitor, CC, in conjunction with the 8 kΩ
internal input scaling resistor, determines the −3 dB low frequency
roll-off. This frequency, FL, is equal to
RAPID SETTLING TIMES VIA THE AVERAGE
RESPONDING CONNECTION
Because the average responding connection shown in Figure 25
does not use an averaging capacitor, its settling time does not vary
with input signal level; it is determined solely by the RC time
constant of CF and the internal 8 kΩ output scaling resistor.
1
FL =
(1)
2π × 8000 ×CC
(
inFarads
)
Note that, at FL, the amplitude error is approximately −30%
(−3 dB) of reading. To reduce this error to 0.5% of reading,
choose a value of CC that sets FL at one-tenth of the lowest
frequency to be measured.
8kΩ
AD737
C
1
2
3
4
8
C
COM
FULL-WAVE
RECTIFIER
In addition, if the input voltage has more than 100 mV of dc
offset, the ac coupling network at Pin 2 is required in addition
to Capacitor CC.
+
C
F
+V
7
6
V
S
IN
8kΩ
33µF
INPUT
AMPLIFIER
POWER
DOWN
BIAS
V
OUT
SECTION
SCALING INPUT AND OUTPUT VOLTAGES
OUTPUT
The AD737 is an extremely flexible device. With minimal
external circuitry, it can be powered with single- or dual-
polarity power supplies, and input and output voltages are
independently scalable to accommodate nonmatching I/O
devices. This section describes a few such applications.
RMS
CORE
–V
S
5
C
AV
+V
POSITIVE SUPPLY
COMMON
S
0.1µF
0.1µF
Extending or Scaling the Input Range
–V
NEGATIVE SUPPLY
S
For low supply voltage applications, the maximum peak voltage
to the device is extended by simply applying the input voltage to
Pin 1 across the internal 8 kΩ input resistor. The AD737 input
circuit functions quasi-differentially, with a high impedance
FET input at Pin 2 (noninverting) and a low impedance input at
Pin 1 (inverting, see Figure 25). The internal 8 kΩ resistor behaves
as a voltage-to-current converter connected to the summing
node of a feedback loop around the input amplifier. Because the
feedback loop acts to servo the summing node voltage to match
the voltage at Pin 2, the maximum peak input voltage increases
until the internal circuit runs out of headroom, approximately
double for a symmetrical dual supply.
Figure 25. AD737 Average Responding Circuit
Selectable Average or RMS Conversion
For some applications, it is desirable to be able to select between
rms-value-to-dc conversion and average-value-to-dc conversion.
If CAV is disconnected from the root-mean core, the AD737 full-
wave rectifier is a highly accurate absolute value circuit. A CMOS
switch whose gate is controlled by a logic level selects between
average and rms values.
Rev. I | Page 14 of 24
Data Sheet
AD737
Battery Operation
Next, using the IOUTMAG value from Equation 2, calculate the new
feedback resistor value (R5) required for 6 V output using
All the level-shifting for battery operation is provided by
the 3½ digit converter, shown in Figure 27. Alternatively, an
external op amp adds flexibility by accommodating nonzero
common-mode voltages and providing output scaling and
offset to zero. When an external operational amplifier is used,
the output polarity is positive going.
6 V
125μA
R5 =
= 48.1kΩ
(3)
Select the closest-value standard 1% resistor, 47.5 kΩ.
Because the supply is 12 V, the common-mode voltage at the
R7/R8 divider is 6 V, and the combined resistor value
(R3 + R4) is equal to the feedback resistor, or 47.5 kΩ.
Figure 28 shows an op amp used in a single-supply application.
Note that the combined input resistor value (R1 + R2 + 8 kΩ)
matches that of the R5 feedback resistor. In this instance, the
magnitudes of the output dc voltage and the rms of the ac input
are equal. R3 and R4 provide current to offset the output to 0 V.
R2 is used to calibrate the transfer function (gain), and R4 sets
the output voltage to zero with no input voltage.
Perform calibration as follows:
Scaling the Output Voltage
1. With no ac input applied, adjust R4 for 0 V.
2. Apply a known input to the input.
3. Adjust the R2 trimmer until the input and output match.
The output voltage can be scaled to the input rms voltage. For
example, assume that the AD737 is retrofitted to an existing
application using an averaging responding circuit (full-wave
rectifier). The power supply is 1 2 V, the input voltage is 10 V
ac, and the desired output is 6 V dc.
The op amp selected for any single-supply application must be a
rail-to-rail type, for example an AD8541, as shown in Figure 28.
For higher voltages, a higher voltage part, such as an OP196,
can be used. When calibrating to 0 V, the specified voltage
above ground for the operational amplifier must be taken into
account. Adjust R4 slightly higher as appropriate.
For convenience, use the same combined input resistance as
shown in Figure 28. Calculate the rms input current as
10 V
IINMAG
=
=125µA = IOUTMAG (2)
69.8 kΩ + 2.5 kΩ + 8 kΩ
Table 6. AD737 Capacitor Selection
Low Frequency
Cutoff (−3 dB)
Maximum
Crest Factor
Application
RMS Input Level
CAV (µF)
CF(µF)
Settling Time1 to 1%
General-Purpose RMS
Computation
0 V to 1 V
20 Hz
5
150
10
360 ms
200 Hz
20 Hz
200 Hz
20 Hz
5
5
5
15
33
3.3
None
1
10
1
36 ms
360 ms
36 ms
1.2 sec
0 mV to 200 mV
0 V to 1 V
General-Purpose Average
Responding
33
200 Hz
20 Hz
200 Hz
50 Hz
None
None
None
100
3.3
33
3.3
33
120 ms
1.2 sec
120 ms
1.2 sec
0 mV to 200 mV
0 mV to 200 mV
SCR Waveform
Measurement
5
60 Hz
50 Hz
60 Hz
5
5
5
82
50
47
27
33
27
1.0 sec
1.2 sec
1.0 sec
0 mV to 100 mV
Audio Applications
Speech
0 mV to 200 mV
0 mV to 100 mV
300 Hz
20 Hz
3
10
1.5
100
0.5
68
18 ms
2.4 sec
Music
1 Settling time is specified over the stated rms input level with the input signal increasing from zero. Settling times are greater for decreasing amplitude input signals.
Rev. I | Page 15 of 24
AD737
Data Sheet
SWITCH CLOSED
ACTIVATES
POWER-DOWN
+
C
10µF
1µF
C
20kΩ
MODE. AD737 DRAWS
JUST 40µA IN THIS MODE
+V
S
+
AD589
1.23V
1
3 /
2 DIGIT ICL7136
TYPE CONVERTER
200kΩ
50kΩ
1PRV
0.01µF
200mV
C
C
COM
8
8kΩ
AD737
V
1
IN
REF HIGH
1N4148
9MΩ
FULL-WAVE
RECTIFIER
+V
S
V
IN
2
2V
REF LOW
COMMON
7
+V
8kΩ
900kΩ
90kΩ
10kΩ
47kΩ
INPUT
AMPLIFIER
20V
1W
OUTPUT
6
1MΩ
1N4148
+
BIAS
LOW
3
9V
200V
SECTION
POWER
DOWN
0.1µF
ANALOG
C
–V
S
4
AV
HIGH
RMS
CORE
5
1µF
–V
+
S
+
33µF
Figure 27. 3½ Digit DVM Circuit
INPUT SCALE FACTOR ADJ
R1 R2
C1
69.8kΩ 5kΩ
C
F
0.47µF
1%
0.47µF
COM
1
2
3
C
V
8
7
6
INPUT
NC
5V
C
R4
5kΩ
R3
78.7kΩ
R5
80.6kΩ
+V
S
IN
5V
C2
0.01µF
AD737
OUTPUT ZERO
ADJUST
0.01µF
1
POWER
DOWN
OUTPUT
2
3
7
6
OUTPUT
AD8541AR
5
4
C
4
–V
S
5
AV
C3
0.01µF
5V
+
C4
2.2µF
C
R7
100kΩ
AV
33µF
2.5V
+
R8
100kΩ
C5
1µF
NC = NO CONNECT
Figure 28. Battery-Powered Operation for 200 mV Maximum RMS Full-Scale Input
C
C
10µF
+
100Ω
SCALE FACTOR
ADJUST
COM
8kΩ
AD737
C
1
2
3
8
C
200Ω
FULL-WAVE
RECTIFIER
+
C
10µF
F
+V
7
V
S
IN
8kΩ
INPUT
AMPLIFIER
OUTPUT
6
POWER
DOWN
BIAS
SECTION
V
OUT
–V
C
S
4
AV
RMS
CORE
5
+
C
AV
33µF
Figure 29. External Scale Factor Trim
Rev. I | Page 16 of 24
Data Sheet
AD737
14
13
Q1
12
1kΩ
3500PPM/°C
C
10µF
C
PRECISION
RESISTOR
CORP
*
C
C
8kΩ
AD737
+
1
8
7
NC
+V
60.4Ω
COM
TYPE PT/ST
SCALE
FACTOR
TRIM
FULL-WAVE
RECTIFIER
2
3
2kΩ
V
S
IN
8kΩ
INPUT
AMPLIFIER
OUTPUT
31.6kΩ
POWER
DOWN
BIAS
6
2
3
SECTION
dB OUTPUT
100mV/dB
6
AD711
–V
C
S
AV
RMS
CORE
4
5
*
+
11
Q2
10
C
AV
I
REF
9
R
**
R1**
CAL
NC = NO CONNECT
*Q1, Q2 PART OF RCA CA3046 OR SIMILAR NPN TRANSISTOR ARRAY.
4.3V
**R1 + R
IN Ω = 10,000 ×
CAL
0dB INPUT LEVEL IN V
Figure 30. dB Output Connection
OFFSET ADJUST
500kΩ
+V
–V
S
S
1MΩ
1kΩ
C
C
COM
8
499Ω
8kΩ
1
AD737
1kΩ
SCALE
FACTOR
ADJUST
FULL-WAVE
RECTIFIER
V
2
3
7
6
+V
IN
S
INPUT
AMPLIFIER
POWER
DOWN
V
OUT
Figure 31. DC-Coupled Offset Voltage and Scale Factor Trims
Rev. I | Page 17 of 24
AD737
Data Sheet
AD737 EVALUATION BOARD
An evaluation board, AD737-EVALZ, is available for experi-
ments or for becoming familiar with rms-to-dc converters.
Figure 32 is a photograph of the board; Figure 34 to Figure 37
show the signal and power plane copper patterns. The board
is designed for multipurpose applications and can be used for
the AD736 as well. Although not shipped with the board, an
optional socket that accepts the 8lead surface-mount package
is available from Enplas Corp.
Figure 34. AD737 Evaluation Board—Component-Side Copper
Figure 32. AD737 Evaluation Board
Figure 35. AD737 Evaluation Board—Secondary-Side Copper
Figure 33. AD737 Evaluation Board—Component-Side Silkscreen
As described in the Applications Information section, the AD737
can be connected in a variety of ways. As shipped, the board is
configured for dual supplies with the high impedance input
connected and the power-down feature disabled. Jumpers are
provided for connecting the input to the low impedance input
(Pin 1) and for dc connections to either input. The schematic
with movable jumpers is shown in Figure 38. The jumper positions
in black are default connections; the dotted-outline jumpers are
optional connections. The board is tested prior to shipment and
requires only a power supply connection and a precision meter to
perform measurements.
Figure 36. AD737 Evaluation Board—Internal Power Plane
Figure 37. AD737 Evaluation Board—Internal Ground Plane
Rev. I | Page 18 of 24
Data Sheet
AD737
GND1 GND2 GND3 GND4
–V
–V
+V
+V
S
S
S
S
C2
10µF
25V
C1
10µF
25V
+
+
W3
W1
AC COUP
LO-Z
DC
W4
LO-Z IN
R3
0Ω
COUP
+
CC
DUT
AD737
V
IN
C
IN
0.1µF
P2
R4
0Ω
J1
HI-Z SEL
HI-Z
1
8
7
6
5
COM
C
V
C
IN
2
3
IN
V
+V
S
OUT
GND
+V
S
W2
C6
0.1µF
POWER
DOWN
OUTPUT
J2
R1
1MΩ
C
F1
CAV
4
–V
S
C
+
V
AV
S
J3
C
33µF
16V
AV
PD
FILT
–V
S
+
NORM
C4
0.1µF
SEL
PIN3
C
F2
Figure 38. AD737 Evaluation Board Schematic
Rev. I | Page 19 of 24
AD737
Data Sheet
OUTLINE DIMENSIONS
5.00 (0.1968)
4.80 (0.1890)
8
1
5
4
6.20 (0.2441)
5.80 (0.2284)
4.00 (0.1574)
3.80 (0.1497)
0.50 (0.0196)
0.25 (0.0099)
1.27 (0.0500)
BSC
45°
1.75 (0.0688)
1.35 (0.0532)
0.25 (0.0098)
0.10 (0.0040)
8°
0°
0.51 (0.0201)
0.31 (0.0122)
COPLANARITY
0.10
1.27 (0.0500)
0.40 (0.0157)
0.25 (0.0098)
0.17 (0.0067)
SEATING
PLANE
COMPLIANT TO JEDEC STANDARDS MS-012-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 39. 8-Lead Standard Small Outline Package [SOIC_N]
Narrow Body
(R-8)
Dimensions shown in millimeters and (inches)
0.400 (10.16)
0.365 (9.27)
0.355 (9.02)
8
1
5
4
0.280 (7.11)
0.250 (6.35)
0.240 (6.10)
0.325 (8.26)
0.310 (7.87)
0.300 (7.62)
0.100 (2.54)
BSC
0.060 (1.52)
MAX
0.195 (4.95)
0.130 (3.30)
0.115 (2.92)
0.210 (5.33)
MAX
0.015
(0.38)
MIN
0.150 (3.81)
0.130 (3.30)
0.115 (2.92)
0.015 (0.38)
GAUGE
0.014 (0.36)
0.010 (0.25)
0.008 (0.20)
PLANE
SEATING
PLANE
0.022 (0.56)
0.018 (0.46)
0.014 (0.36)
0.430 (10.92)
MAX
0.005 (0.13)
MIN
0.070 (1.78)
0.060 (1.52)
0.045 (1.14)
COMPLIANT TO JEDEC STANDARDS MS-001
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.
CORNER LEADS MAY BE CONFIGURED AS WHOLE OR HALF LEADS.
Figure 40. 8-Lead Plastic Dual-In-Line Package [PDIP]
(N-8)
Dimensions shown in inches and (millimeters)
Rev. I | Page 20 of 24
Data Sheet
AD737
ORDERING GUIDE
Model1
Temperature Range
−40°C to +85°C
−40°C to +85°C
0°C to 70°C
Package Description
Package Option
AD737ANZ
AD737ARZ
AD737JNZ
8-Lead Plastic Dual In-Line Package [PDIP]
8-Lead Standard Small Outline Package [SOIC_N]
8-Lead Plastic Dual In-Line Package [PDIP]
8-Lead Standard Small Outline Package [SOIC_N]
8-Lead Standard Small Outline Package [SOIC_N]
8-Lead Standard Small Outline Package [SOIC_N]
8-Lead Standard Small Outline Package [SOIC_N]
8-Lead Standard Small Outline Package [SOIC_N]
8-Lead Standard Small Outline Package [SOIC_N]
8-Lead Standard Small Outline Package [SOIC_N]
8-Lead Standard Small Outline Package [SOIC_N]
8-Lead Standard Small Outline Package [SOIC_N]
8-Lead Standard Small Outline Package [SOIC_N]
Evaluation Board
N-8
R-8
N-8
R-8
R-8
R-8
R-8
R-8
R-8
R-8
R-8
R-8
R-8
AD737JRZ
0°C to 70°C
AD737JRZ-R7
AD737JRZ-RL
AD737JRZ-5
0°C to 70°C
0°C to 70°C
0°C to 70°C
AD737JRZ-5-R7
AD737JRZ-5-RL
AD737KR-REEL
AD737KR-REEL7
AD737KRZ-RL
AD737KRZ-R7
AD737-EVALZ
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
1 Z = RoHS Compliant Part.
Rev. I | Page 21 of 24
AD737
NOTES
Data Sheet
Rev. I | Page 22 of 24
Data Sheet
NOTES
AD737
Rev. I | Page 23 of 24
AD737
NOTES
Data Sheet
©2012 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective owners.
D00828-0-6/12(I)
Rev. I | Page 24 of 24
相关型号：
SI9130DB
5- and 3.3-V Step-Down Synchronous ConvertersWarning: Undefined variable $rtag in /www/wwwroot/website_ic37/www.icpdf.com/pdf/pdf/index.php on line 217
-
VISHAY
SI9135LG-T1
SMBus Multi-Output Power-Supply ControllerWarning: Undefined variable $rtag in /www/wwwroot/website_ic37/www.icpdf.com/pdf/pdf/index.php on line 217
-
VISHAY
SI9135LG-T1-E3
SMBus Multi-Output Power-Supply ControllerWarning: Undefined variable $rtag in /www/wwwroot/website_ic37/www.icpdf.com/pdf/pdf/index.php on line 217
-
VISHAY
SI9135_11
SMBus Multi-Output Power-Supply ControllerWarning: Undefined variable $rtag in /www/wwwroot/website_ic37/www.icpdf.com/pdf/pdf/index.php on line 217
-
VISHAY
SI9136_11
Multi-Output Power-Supply ControllerWarning: Undefined variable $rtag in /www/wwwroot/website_ic37/www.icpdf.com/pdf/pdf/index.php on line 217
-
VISHAY
SI9130CG-T1-E3
Pin-Programmable Dual Controller - Portable PCsWarning: Undefined variable $rtag in /www/wwwroot/website_ic37/www.icpdf.com/pdf/pdf/index.php on line 217
-
VISHAY
SI9130LG-T1-E3
Pin-Programmable Dual Controller - Portable PCsWarning: Undefined variable $rtag in /www/wwwroot/website_ic37/www.icpdf.com/pdf/pdf/index.php on line 217
-
VISHAY
SI9130_11
Pin-Programmable Dual Controller - Portable PCsWarning: Undefined variable $rtag in /www/wwwroot/website_ic37/www.icpdf.com/pdf/pdf/index.php on line 217
-
VISHAY
SI9137
Multi-Output, Sequence Selectable Power-Supply Controller for Mobile ApplicationsWarning: Undefined variable $rtag in /www/wwwroot/website_ic37/www.icpdf.com/pdf/pdf/index.php on line 217
-
VISHAY
SI9137DB
Multi-Output, Sequence Selectable Power-Supply Controller for Mobile ApplicationsWarning: Undefined variable $rtag in /www/wwwroot/website_ic37/www.icpdf.com/pdf/pdf/index.php on line 217
-
VISHAY
SI9137LG
Multi-Output, Sequence Selectable Power-Supply Controller for Mobile ApplicationsWarning: Undefined variable $rtag in /www/wwwroot/website_ic37/www.icpdf.com/pdf/pdf/index.php on line 217
-
VISHAY
SI9122E
500-kHz Half-Bridge DC/DC Controller with Integrated Secondary Synchronous Rectification DriversWarning: Undefined variable $rtag in /www/wwwroot/website_ic37/www.icpdf.com/pdf/pdf/index.php on line 217
-
VISHAY
©2020 ICPDF网 联系我们和版权申明