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Электронный компонент: ADM4073

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Low Cost, Voltage Output,
High-Side, Current-Sense Amplifier
ADM4073
Rev. 0
Information furnished by Analog Devices is believed to be accurate and reliable. However, no
responsibility is assumed by Analog Devices for its use, nor for any infringements of patents or other
rights of third parties that may result from its use. Specifications subject to change without notice. No
license is granted by implication or otherwise under any patent or patent rights of Analog Devices.
Trademarks and registered trademarks are the property of their respective owners.


One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: 781.329.4700
www.analog.com
Fax: 781.461.3113
2006 Analog Devices, Inc. All rights reserved.
FEATURES
Low cost, compact, current-sense solution
Three available gain versions
20 V/V (ADM4073T)
50 V/V (ADM4073F)
100 V/V (ADM4073H)
Typical 1.0% full-scale accuracy
500 A supply current
Wide 1.8 MHz bandwidth
3 V to 28 V operating supply
Wide 2 V to 28 V common-mode range
Independent of supply voltage
Operates from -40C to +125C
Available in a 6-lead SOT-23 package
Pin-to-pin compatibility with the MAX4073
APPLICATIONS
Cell phones, PDAs
Notebook computers
Portable/battery-powered systems
Smart battery packs/chargers
Automotive
Power management systems
PA bias control
General system/board-level current monitoring
Precision current sources
FUNCTIONAL BLOCK DIAGRAM
2V TO 28V
3V TO 28V
0.1F
V
OUT
R
SENSE
I
LOAD
I
RG1
V
OUT
RS+
GND
AV
RS
V
CC
RG2
RGD = 12k
RG1
ADM4073
I
RGD
CURRENT
MIRROR
05131-
003
Figure 1.
APPLICATION DIAGRAM
2V TO 28V
3V TO 28V
0.1F
V
OUT
R
SENSE
OUT
ADC
RS+
GND
RS
V
CC
ADM4073
0
513
1-
0
01
Figure 2.
GENERAL DESCRIPTION
The ADM4073 is a low cost, high-side, current-sense amplifier
ideal for small portable applications such as cell phones,
notebook computers, PDAs, and other systems where current
monitoring is required. The device is available in three different
gain models, eliminating the need for gain-setting resistors.
Because the ground path is not interrupted, the ADM4073 is
particularly useful in rechargeable battery-powered systems,
while its wide 1.8 MHz bandwidth makes it suitable for use
inside battery-charger control loops. The input common-mode
range of 2 V to 28 V is independent of the supply voltage.
The voltage on the output pin is determined by the current
flowing through the selectable external sense resistor and the
gain of the version selected. The operating range is 3 V to 28 V
with a typical supply current of 500 A. The ADM4073 is
available in a 6-lead SOT-23 package and is specified over the
automotive operating temperature range (-40C to +125C).
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ADM4073
Rev. 0 | Page 2 of 12
TABLE OF CONTENTS
Features .............................................................................................. 1
Applications....................................................................................... 1
Functional Block Diagram .............................................................. 1
Application Diagram........................................................................ 1
General Description ......................................................................... 1
Revision History ............................................................................... 2
Specifications..................................................................................... 3
Absolute Maximum Ratings............................................................ 4
Thermal Characteristics .............................................................. 4
ESD Caution...................................................................................4
Pin Configuration and Function Descriptions..............................5
Typical Performance Characteristics ..............................................6
Theory of Operation ...................................................................... 10
R
SENSE
............................................................................................. 10
Output (OUT)............................................................................. 10
Outline Dimensions ....................................................................... 11
Ordering Guide .......................................................................... 11
REVISION HISTORY
7/06--Revision 0: Initial Version
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ADM4073
Rev. 0 | Page 3 of 12
SPECIFICATIONS
V
RS+
= 2 V to 28 V, V
SENSE
= (V
RS+
- V
RS-
) = 0, V
CC
= 3 V to 28 V, T
A
= -40C to +125C, unless otherwise noted. Typical values are at T
A
= 25C.
1
Table 1.
Parameter
Min Typ Max Unit Conditions
POWER SUPPLY
Operating Voltage Range, V
CC
3
28
V
Inferred from PSRR test
Common-Mode Input Range, V
CMR
2
28
V
Inferred OUT voltage error test
Common-Mode Input Rejection, CMR
90
dB
V
SENSE
= 100 mV, V
CC
= 12 V
Supply Current, I
CC
0.5
1.2
mA
V
CC
= 28 V
Leakage Current, I
RS+
/I
RS-
0.05
2
A
V
CC
= 0 V, V
RS+
= 28 V, T
A
= 85C
Input Bias Current, I
RS+
20
60
A
Input Bias Current, I
RS-
40
120
A
Full Scale Sense Voltage, V
SENSE
150
mV
V
SENSE
= (V
RS+
- V
RS-
)
Total Out Voltage Error
2
1
%
V
SENSE
= 100 mV, V
CC
= 12 V, V
RS+
= 2 V
1.0
5.0
%
V
SENSE
= 100 mV, V
CC
= 12 V, V
RS+
= 12 V, T
A
= +25C
5.0
%
V
SENSE
= 100 mV, V
CC
= 12 V, V
RS
= 12V, T
A
= -40C to +125C
1.0
5.0
%
V
SENSE
= 100 mV, V
CC
= 28 V, V
RS
= 28 V, T
A
= +25C
5.0
%
V
SENSE
= 100 mV, V
CC
= 28 V, V
RS
= 28 V, T
A
= -40C to +125C
7.5
%
V
SENSE
= 6.25 mV,
3
V
CC
= 12 V, V
RS
= 12 V
Extrapolated Input Offset Voltage, V
OS
1.0 mV V
CC
= V
RS+
= 12 V, V
SENSE
> 10 mV
Out High Voltage (V
CC
- V
OH
)
0.8
1.2
V
V
CC
= 3 V, V
SENSE
= 150 mV (ADM4073T)
0.8
1.2
V
V
CC
= 7.5 V, V
SENSE
= 150 mV (ADM4073F)
0.8
1.2
V
V
CC
= 15 V, V
SENSE
= 150 mV (ADM4073H), T
A
= 25C
DYNAMIC CHARACTERISTICS
Bandwidth, BW
1.8
MHz
V
SENSE
= 100 mV, V
CC
= 12 V, V
RS+
= 12 V, C
LOAD
= 5 pF (ADM4073T)
1.7
MHz
V
SENSE
= 100 mV, V
CC
= 12 V, V
RS+
= 12 V, C
LOAD
= 5 pF (ADM4073F)
1.6
MHz
V
SENSE
= 100 mV, V
CC
= 12 V, V
RS+
= 12 V, C
LOAD
= 5 pF (ADM4073H)
600
kHz
V
SENSE
= 6.25 mV,
3
V
CC
= 12 V, V
RS+
= 12 V, C
LOAD
= 5 pF (ADM4073T/F/H)
Gain, A
V
20
V/V
ADM4073T
50
V/V
ADM4073F
100
V/V
ADM4073H
Gain Accuracy, dA
V
1.0
2.0
%
V
SENSE
= 10 mV to 150 mV, V
CC
= 12 V, V
RS+
= 12 V,
T
A
= +25C (ADM4073T/F)
2.0
%
V
SENSE
= 10 mV to 150 mV, V
CC
= 12 V, V
RS+
= 12 V,
T
A
= -40C to +125C (ADM4073T/F)
1.0
1.5
%
V
SENSE
= 10 mV to 100 mV, V
CC
= 12 V, V
RS+
= 12 V,
T
A
= +25C (ADM4073H)
3.0
%
V
SENSE
= 10 mV to 100 mV, V
CC
= 12 V, V
RS+
= 12 V,
T
A
= -40C to +125C (ADM4073H)
OUT Settling Time to 1% of Final Value
400
ns
V
SENSE
= 6.25 mV to 100 mV, V
CC
= 12 V, V
RS+
= 12 V, C
LOAD
= 5 pF
800
ns
V
SENSE
= 100 mV to 6.25 mV, V
CC
= 12 V, V
RS+
= 12 V, C
LOAD
= 5 pF
Output Resistance, R
OUT
12
k
Power Supply Rejection Ratio, PSRR
78
dB
V
SENSE
= 60 mV, V
CC
= 3 V to 28 V (ADM4073T)
85
dB
V
SENSE
= 24 mV, V
CC
= 3 V to 28 V (ADM4073F)
90
dB
V
SENSE
= 12 mV, V
CC
= 3 V to 28 V (ADM4073H)
Power-Up Time
4
5 s
C
LOAD
= 5 pF, V
SENSE
= 100 mV
Saturation Recovery Time
5
5 s
C
LOAD
= 5 pF, V
CC
= 12 V, V
RS+
= 12 V
1
100% production tested at T
A
= 25C. Specifications over temperature limit are guaranteed by design.
2
Total out voltage error is the sum of the gain and offset errors.
3
6.25 mV = 1/16
th
of 100 mV full-scale sense voltage.
4
Output settles to within 1% of final value.
5
The device does not experience phase reversal when overdriven.
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ADM4073
Rev. 0 | Page 4 of 12
ABSOLUTE MAXIMUM RATINGS
Table 2.
Parameter Rating
V
CC
to GND
-0.3 V to +30 V
RS to GND
-0.3 V to +30 V
OUT to GND
-0.3 V to (V
CC
+ 0.3 V)
OUT Short-Circuit to GND
Continuous
Differential Input Voltage (V
RS+
- V
RS-
) 5
V
Current into any Pin
20 mA
Storage Temperature Range
-65C to +125C
Operating Temperature Range
-40C to +125C
Lead Temperature, Soldering (10 sec)
300C
Junction Temperature
150C
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.
THERMAL CHARACTERISTICS
JA
is specified for the worst-case conditions, that is, a device
soldered in a circuit board for surface-mount packages.
Table 3. Thermal Resistance
Package Type
JA
Unit
6-Lead SOT-23
169.5
C/W
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.
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ADM4073
Rev. 0 | Page 5 of 12
PIN CONFIGURATION AND FUNCTION DESCRIPTIONS
GND
1
GND
2
V
CC
3
OUT
6
RS
5
RS+
4
ADM4073xWRJ
TOP VIEW
(Not to Scale)
0
513
1-
00
2
Figure 3. Pin Configuration
Table 4. Pin Function Descriptions
Pin No.
Mnemonic
Description
1, 2
GND
Chip Ground Pin.
3 V
CC
Chip Power Supply. Requires a 0.1F capacitor to ground.
4
RS+
Power-Side Connection to the External Sense Resistor.
5
RS-
Load-Side Connection to the External Sense Resistor.
6 OUT Voltage Output. V
OUT
is proportional to V
SENSE
. Output impedence is approximately 12 k
.
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ADM4073
Rev. 0 | Page 6 of 12
TYPICAL PERFORMANCE CHARACTERISTICS
0.60
0.30
0
30
SUPPLY VOLTAGE (V)
S
UP
P
L
Y
CURR
E
NT
(
m
A)
5
10
15
20
25
ADM4073H
ADM4073T
ADM4073F
V
SENSE
= 6.25mV
0.55
0.50
0.45
0.40
0.35
05
13
1-
0
05
Figure 4. Supply Current vs. Supply Voltage (V
SENSE
= 6.25mV)
1.5
0.5
0
30
0.45
0.35
0
30
V
RS+
(V)
S
UP
P
L
Y
CU
RRE
NT
(
m
A)
ADM4073H
ADM4073T
ADM4073F
0.43
0.41
0.39
0.37
5
10
15
20
25
V
SENSE
= 6.25mV
0
51
31-
00
8
SUPPLY VOLTAGE (V)
S
UP
P
L
Y
CU
RRE
NT

(
m
A)
5
10
15
20
25
ADM4073H
ADM4073T
ADM4073F
V
SENSE
= 100mV
1.4
1.3
1.2
1.1
1.0
0.9
0.8
0.7
0.6
05
13
1-
0
06
Figure 5. Supply Current vs. Supply Voltage (V
SENSE
= 100 mV)
0.7
0
50
150
TEMPERATURE (C)
S
UP
P
L
Y
CU
RRE
N
T
(
m
A)
0.6
0.5
0.4
0.3
0.2
0.1
V
SENSE
= 0mV
V
CC
= 28V
25
0
25
50
75
100
125
05
13
1-
00
7
Figure 6. Supply Current vs. Temperature
Figure 7. Supply Current vs. RS+ Voltage (V
SENSE
= 6.25 mV)
1.5
0.5
0
30
V
RS+
(V)
S
U
P
P
L
Y
C
URRE
NT

(
m
A)
ADM4073H
ADM4073T
ADM4073F
1.3
1.1
0.9
0.7
5
10
15
20
25
V
SENSE
= 100mV
05
13
1-
00
9
Figure 8. Supply Current vs. RS+ Voltage (V
SENSE
= 100 mV)
1.0
1.0
0
3
SUPPLY VOLTAGE (V)
T
O
TA
L O
U
T
P
U
T E
R
R
O
R
(
%
)
0
5
10
15
20
25
ADM4073H
ADM4073T
ADM4073F
0.8
0.6
0.4
0.2
0
0.2
0.4
0.6
0.8
V
SENSE
= 100mV
0
513
1-
0
10
Figure 9. Total Output Error vs. Supply Voltage (V
SENSE
= 100 mV)
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ADM4073
Rev. 0 | Page 7 of 12
1.0
1.0
0
30
SUPPLY VOLTAGE (V)
T
O
TA
L O
U
T
P
U
T E
R
R
O
R
(
%
)
5
10
15
20
25
ADM4073H
ADM4073T
ADM4073F
0.8
0.6
0.4
0.2
0
0.2
0.4
0.6
0.8
V
SENSE
= 6.25mV
0
513
1-
0
11
Figure 10. Total Output Error vs. Supply Voltage (V
SENSE
= 6.25 mV)
1.0
3.0
0
30
2.0
2.0
50
150
TEMPERATURE (C)
G
AI
N AC
CURA
CY
(
%
)
COMMON-MODE VOLTAGE (V)
T
O
TA
L OU
T
P
U
T E
R
R
O
R
(%
)
5
10
15
20
25
ADM4073H
ADM4073T
ADM4073F
1.0
0.5
0
0.5
1.5
2.0
2.5
0
513
1-
0
12
Figure 11. Total Output Error vs. Common-Mode Voltage
0.10
0.10
50
150
TEMPERATURE (C)
T
O
TA
L OU
T
P
U
T E
R
R
O
R
(%
)
0.08
0.06
0.04
0.02
0
0.02
0.04
0.06
0.08
V
CC
= 28V
V
CC
= 12V
0
50
100
05
13
1-
0
13
Figure 12. Total Output Error vs. Temperature
0
50
100
1.5
1.0
0.5
0
0.5
1.0
1.5
25
25
75
125
0
513
1-
0
14
1.4
0
50
150
TEMPERATURE (C)
V
CC
V
OH
(V
)
Figure 13. Gain Accuracy vs. Temperature
0
513
1-
0
15
1.2
1.0
0.8
0.6
0.4
0.2
ADM4073H
ADM4073F
ADM4073T
0
50
100
Figure 14. O/P High Voltage (V
CC
- V
OH
) vs. Temperature
70
0
0.1
10000
FREQUENCY (kHz)
P
S
RR (
d
B
)
0
513
1-
0
16
60
50
40
30
20
10
1
10
100
1000
ADM4073F
ADM4073T
ADM4073H
Figure 15. PSRR vs. Frequency
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ADM4073
Rev. 0 | Page 8 of 12
45
0
0.1
10000
FREQUENCY (kHz)
G
A
IN
(
d
B
)
0
513
1-
0
17
1
10
100
1000
ADM4073F
ADM4073T
ADM4073H
40
35
30
25
20
15
10
5
Figure 16. Small Signal Gain vs. Frequency
05
13
1-
0
18
1s/DIV
100mV
95mV
2V
1.9V
V
SENSE
2.5mV/DIV
OUT
50mV/DIV
Figure 17. ADM4073T Small Signal Transient Response
05
13
1-
0
19
1s/DIV
100mV
95mV
5V
4.75V
V
SENSE
2.5mV/DIV
OUT
125mV/DIV
Figure 18. ADM4073F Small Signal Transient Response
05
13
1-
0
20
1s/DIV
100mV
95mV
10V
9.5V
V
SENSE
2.5mV/DIV
OUT
250mV/DIV
Figure 19. ADM4073H Small Signal Transient Response
05
13
1-
0
21
1s/DIV
100mV
6.25mV
2V
0.120V
V
SENSE
45mV/DIV
OUT
0.9V/DIV
Figure 20. ADM4073T Large Signal Transient Response
05
13
1-
0
22
1s/DIV
100mV
6.25mV
5V
0.3V
V
SENSE
45mV/DIV
OUT
2.35V/DIV
Figure 21. ADM4073F Large Signal Transient Response
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ADM4073
Rev. 0 | Page 9 of 12
05
13
1-
0
23
1s/DIV
100mV
6.25mV
10V
0.6V
V
SENSE
45mV/DIV
OUT
4.7V/DIV
Figure 22. ADM4073H Large Signal Transient Response
05
13
1-
0
24
1s/DIV
250mV
50mV
V
OH
1V
V
SENSE
100mV/DIV
OUT
600mV/DIV
V
CC
= 3V
Figure 23. ADM4073T Overdrive Response
05
13
1-
0
25
1s/DIV
4V
0V
2V
0V
V
CC
2V/DIV
OUT
1V/DIV
V
CC
= 0V TO 4V
Figure 24. ADM4073T Start-Up Delay
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ADM4073
Rev. 0 | Page 10 of 12
THEORY OF OPERATION
The current from the source flows through R
SENSE
, which
generates a voltage drop, V
SENSE
, across the RS+ and RS-
terminals of the sense amplifier. The Input Stage Amplifier A1
regulates its inputs to be equal, thereby shunting a current
proportional to V
SENSE
/R
G1
to the output current mirror. This
current is then multiplied by a gain factor b in the output stage
current mirror and flows through R
GD
to generate V
OUT
.
Therefore, V
OUT
is related to V
SENSE
by the ratio of R
G1
to R
GD
and
the current gain b.
V
OUT
= A
V
V
SENSE
where:
A
V
= R
GD
/R
G1
b
where:
A
V
= 20 V/V (for ADM4073T).
A
V
= 50 V/V (for ADM4073H).
A
V
= 100 V/V (for ADM4073F).
2V TO 28V
3V TO 28V
0.1F
V
OUT
R
SENSE
I
LOAD
I
RG1
V
OUT
RS+
GND
AV
RS
V
CC
RG2
RGD = 12k
RG1
ADM4073
I
RGD
CURRENT
MIRROR
05131-
0
03
Figure 25. Functional Block Diagram
R
SENSE
The ADM4073 has the ability to sense a wide variety of
currents by selecting a particular sense resistor. Select a suitable
output voltage for full-scale current, for example, 10 V for 10 A.
Then select a gain model that gives the most efficient use of the
sense voltage range (150 mV max).
In the example above, using the ADM4073H (gain of 100) give
an output voltage of 10 V when the sense voltage is 100 mV.
Use the following equation to determine what value of sense
resistor gives 100 mV with 10 A flowing through it:
R
SENSE
= 100 mV/10 A
R
SENSE
= 10 m
To measure lower currents accurately, as large a sense resistor
as possible should be used to utilize the higher end of the sense
voltage range. This reduces the effects of the offset voltage
errors in the internal amplifier.
When currents are very large, it is important to take the I
2
R
power losses across the sense resistor into account. If the sense
resistor's rated power dissipation is not sufficient, its value can
drift, giving an inaccurate output voltage, or it could fail
altogether. This, in turn, causes the voltage across the RS+ and
RS- pins to exceed the absolute maximum ratings.
If the monitored supply rail has a large amplitude high
frequency component, a sense resistor with low inductance
should be chosen.
INPUT
COPPER PCB TRACE
OUTPUT
3V TO 28V
0.1F
R
SENSE
OUT
RS+
GND
RS
V
CC
ADM4073
0
513
1-
0
04
Figure 26. Using PCB Trace for Current Sensing
OUTPUT (OUT)
The output stage of the ADM4073 is a current source driving a
pull-down resistance. To ensure optimum accuracy, care must
be taken not to load this output externally. To minimize output
errors, ensure OUT is connected to a high impedance input
stage. If this is not possible, output buffering is recommended.
The percent error introduced by output loading is determined
with the following formula:
(
)
(
)
1
/
100
%
_
-
+
=
SENSE
INT
OUT
LOAD
R
R
R
Error
where:
R
LOAD
is the external load applied to OUT.
R
OUT_INT
is the internal output resistance (12 k).
V
OUT
= (I
LOAD
R
SENSE
) A
V
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ADM4073
Rev. 0 | Page 11 of 12
OUTLINE DIMENSIONS
1
3
4
5
2
6
2.90 BSC
1.60 BSC
2.80 BSC
1.90
BSC
0.95 BSC
0.22
0.08
10
4
0
0.50
0.30
0.15 MAX
1.30
1.15
0.90
SEATING
PLANE
1.45 MAX
0.60
0.45
0.30
PIN 1
INDICATOR
COMPLIANT TO JEDEC STANDARDS MO-178-AB
Figure 27. 6-Lead Small Outline Transistor Package [SOT-23]
(RJ-6)
Dimensions shown in millimeters
ORDERING GUIDE
Model Gain
Temperature
Range
Package
Description Package
Option Branding
ADM4073TWRJZ-REEL7
1
20
-40C to +125C
6-Lead SOT-23
RJ-6
M2E
ADM4073FWRJZ-REEL7
1
50
-40C to +125C
6-Lead SOT-23
RJ-6
M2C
ADM4073HWRJZ-REEL7
1
100
-40C to +125C
6-Lead SOT-23
RJ-6
M2D
1
Z = Pb-free part.
background image
ADM4073
Rev. 0 | Page 12 of 12
NOTES
2006 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective owners.
D05131-0-7/06(0)

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