AD ADM4073TWRJZ-REEL7 Low cost, voltage output, high-side, current-sense amplifier Datasheet

Low Cost, Voltage Output,
High-Side, Current-Sense Amplifier
ADM4073
FUNCTIONAL BLOCK DIAGRAM
ILOAD
RSENSE
2V TO 28V
0.1µF
IRG1
VCC
RG1
RG2
AV
ADM4073
VOUT
CURRENT
MIRROR
RGD = 12kΩ
IRGD
GND
Figure 1.
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
RS–
RS+
3V TO 28V
VOUT
05131-003
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 μA 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 −40°C to +125°C
Available in a 6-lead SOT-23 package
Pin-to-pin compatibility with the MAX4073
APPLICATION DIAGRAM
RSENSE
2V TO 28V
RS+
3V TO 28V
VOUT
RS–
VCC
OUT
0.1µF
ADC
ADM4073
GND
05131-001
FEATURES
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 μA. The ADM4073 is
available in a 6-lead SOT-23 package and is specified over the
automotive operating temperature range (−40°C to +125°C).
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.
ADM4073
TABLE OF CONTENTS
Features .............................................................................................. 1
ESD Caution...................................................................................4
Applications....................................................................................... 1
Pin Configuration and Function Descriptions..............................5
Functional Block Diagram .............................................................. 1
Typical Performance Characteristics ..............................................6
Application Diagram........................................................................ 1
Theory of Operation ...................................................................... 10
General Description ......................................................................... 1
RSENSE............................................................................................. 10
Revision History ............................................................................... 2
Output (OUT)............................................................................. 10
Specifications..................................................................................... 3
Outline Dimensions ....................................................................... 11
Absolute Maximum Ratings............................................................ 4
Ordering Guide .......................................................................... 11
Thermal Characteristics .............................................................. 4
REVISION HISTORY
7/06—Revision 0: Initial Version
Rev. 0 | Page 2 of 12
ADM4073
SPECIFICATIONS
VRS+ = 2 V to 28 V, VSENSE = (VRS+ − VRS−) = 0, VCC = 3 V to 28 V, TA = −40°C to +125°C, unless otherwise noted. Typical values are at TA = 25°C. 1
Table 1.
Parameter
POWER SUPPLY
Operating Voltage Range, VCC
Common-Mode Input Range, VCMR
Common-Mode Input Rejection, CMR
Supply Current, ICC
Leakage Current, IRS+/IRS−
Input Bias Current, IRS+
Input Bias Current, IRS−
Full Scale Sense Voltage, VSENSE
Total Out Voltage Error 2
Min
Typ
3
2
90
0.5
0.05
20
40
150
±1
±1.0
±1.0
Extrapolated Input Offset Voltage, VOS
Out High Voltage (VCC − VOH)
DYNAMIC CHARACTERISTICS
Bandwidth, BW
Gain, AV
Gain Accuracy, dAV
±7.5
1.0
0.8
0.8
0.8
1.8
1.7
1.6
600
20
50
100
±1.0
±1.0
OUT Settling Time to 1% of Final Value
Output Resistance, ROUT
Power Supply Rejection Ratio, PSRR
Power-Up Time 4
Saturation Recovery Time 5
400
800
12
78
85
90
5
5
Max
Unit
Conditions
28
28
Inferred from PSRR test
Inferred OUT voltage error test
VSENSE = 100 mV, VCC = 12 V
VCC = 28 V
VCC = 0 V, VRS+ = 28 V, TA = 85°C
1.2
1.2
1.2
V
V
dB
mA
μA
μA
μA
mV
%
%
%
%
%
%
mV
V
V
V
±2.0
MHz
MHz
MHz
kHz
V/V
V/V
V/V
%
±2.0
%
±1.5
%
±3.0
%
VSENSE = 100 mV, VCC = 12 V, VRS+ = 12 V, CLOAD = 5 pF (ADM4073T)
VSENSE = 100 mV, VCC = 12 V, VRS+ = 12 V, CLOAD = 5 pF (ADM4073F)
VSENSE = 100 mV, VCC = 12 V, VRS+ = 12 V, CLOAD = 5 pF (ADM4073H)
VSENSE = 6.25 mV,3 VCC = 12 V, VRS+ = 12 V, CLOAD = 5 pF (ADM4073T/F/H)
ADM4073T
ADM4073F
ADM4073H
VSENSE = 10 mV to 150 mV, VCC = 12 V, VRS+ = 12 V,
TA = +25°C (ADM4073T/F)
VSENSE = 10 mV to 150 mV, VCC = 12 V, VRS+ = 12 V,
TA = −40°C to +125°C (ADM4073T/F)
VSENSE = 10 mV to 100 mV, VCC = 12 V, VRS+ = 12 V,
TA = +25°C (ADM4073H)
VSENSE = 10 mV to 100 mV, VCC = 12 V, VRS+ = 12 V,
TA = −40°C to +125°C (ADM4073H)
VSENSE = 6.25 mV to 100 mV, VCC = 12 V, VRS+ = 12 V, CLOAD = 5 pF
VSENSE = 100 mV to 6.25 mV, VCC = 12 V, VRS+ = 12 V, CLOAD = 5 pF
1.2
2
60
120
±5.0
±5.0
±5.0
±5.0
ns
ns
kΩ
dB
dB
dB
μs
μs
VSENSE = (VRS+ − VRS−)
VSENSE = 100 mV, VCC = 12 V, VRS+ = 2 V
VSENSE = 100 mV, VCC = 12 V, VRS+ = 12 V, TA = +25°C
VSENSE = 100 mV, VCC = 12 V, VRS = 12V, TA = −40°C to +125°C
VSENSE = 100 mV, VCC = 28 V, VRS = 28 V, TA = +25°C
VSENSE = 100 mV, VCC = 28 V, VRS = 28 V, TA = −40°C to +125°C
VSENSE = 6.25 mV, 3 VCC = 12 V, VRS = 12 V
VCC = VRS+ = 12 V, VSENSE > 10 mV
VCC = 3 V, VSENSE = 150 mV (ADM4073T)
VCC = 7.5 V, VSENSE = 150 mV (ADM4073F)
VCC = 15 V, VSENSE = 150 mV (ADM4073H), TA = 25°C
VSENSE = 60 mV, VCC = 3 V to 28 V (ADM4073T)
VSENSE = 24 mV, VCC = 3 V to 28 V (ADM4073F)
VSENSE = 12 mV, VCC = 3 V to 28 V (ADM4073H)
CLOAD = 5 pF, VSENSE = 100 mV
CLOAD = 5 pF, VCC = 12 V, VRS+ = 12 V
1
100% production tested at TA = 25°C. Specifications over temperature limit are guaranteed by design.
Total out voltage error is the sum of the gain and offset errors.
3
6.25 mV = 1/16th 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.
2
Rev. 0 | Page 3 of 12
ADM4073
ABSOLUTE MAXIMUM RATINGS
Table 2.
Parameter
VCC to GND
RS± to GND
OUT to GND
OUT Short-Circuit to GND
Differential Input Voltage (VRS+ − VRS−)
Current into any Pin
Storage Temperature Range
Operating Temperature Range
Lead Temperature, Soldering (10 sec)
Junction Temperature
Rating
−0.3 V to +30 V
−0.3 V to +30 V
−0.3 V to (VCC + 0.3 V)
Continuous
±5 V
±20 mA
−65°C to +125°C
−40°C to +125°C
300°C
150°C
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
θJA 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
6-Lead SOT-23
ESD CAUTION
ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily accumulate on
the human body and test equipment and can discharge without detection. Although this product features
proprietary ESD protection circuitry, permanent damage may occur on devices subjected to high energy
electrostatic discharges. Therefore, proper ESD precautions are recommended to avoid performance
degradation or loss of functionality.
Rev. 0 | Page 4 of 12
θJA
169.5
Unit
°C/W
ADM4073
PIN CONFIGURATION AND FUNCTION DESCRIPTIONS
ADM4073xWRJ
GND 1
6
OUT
VCC 3
4
RS+
05131-002
TOP VIEW
GND 2 (Not to Scale) 5 RS–
Figure 3. Pin Configuration
Table 4. Pin Function Descriptions
Pin No.
1, 2
3
4
5
6
Mnemonic
GND
VCC
RS+
RS−
OUT
Description
Chip Ground Pin.
Chip Power Supply. Requires a 0.1μF capacitor to ground.
Power-Side Connection to the External Sense Resistor.
Load-Side Connection to the External Sense Resistor.
Voltage Output. VOUT is proportional to VSENSE. Output impedence is approximately 12 kΩ.
Rev. 0 | Page 5 of 12
ADM4073
TYPICAL PERFORMANCE CHARACTERISTICS
0.45
0.60
VSENSE = 6.25mV
VSENSE = 6.25mV
0.43
SUPPLY CURRENT (mA)
0.50
ADM4073H
0.45
ADM4073F
0.40
ADM4073T
ADM4073T
0.39
ADM4073F
5
10
15
20
25
30
SUPPLY VOLTAGE (V)
0.35
05131-005
0
0
VSENSE = 100mV
SUPPLY CURRENT (mA)
1.1
1.0
0.9
ADM4073F
0.7
1.1
0.9
10
15
20
25
30
05131-006
0.5
5
0
ADM4073F
ADM4073T
0
5
10
15
20
25
30
30
VRS+ (V)
Figure 8. Supply Current vs. RS+ Voltage (VSENSE = 100 mV)
Figure 5. Supply Current vs. Supply Voltage (VSENSE = 100 mV)
0.7
1.0
VSENSE = 0mV
VCC = 28V
VSENSE = 100mV
TOTAL OUTPUT ERROR (%)
0.8
0.5
0.4
0.3
0.2
0.6
ADM4073F
0.4
ADM4073T
0.2
0
ADM4073H
–0.2
–0.4
–0.6
0.1
–0.8
0
–50
–25
0
25
50
75
100
TEMPERATURE (°C)
125
150
–1.0
05131-007
SUPPLY CURRENT (mA)
ADM4073H
ADM4073T
SUPPLY VOLTAGE (V)
0.6
30
1.3
0.7
0.6
25
05131-009
SUPPLY CURRENT (mA)
ADM4073H
1.2
0.5
20
VSENSE = 100mV
1.5
0.8
15
Figure 7. Supply Current vs. RS+ Voltage (VSENSE = 6.25 mV)
1.5
1.3
10
VRS+ (V)
Figure 4. Supply Current vs. Supply Voltage (VSENSE = 6.25mV)
1.4
5
05131-008
0.37
0.35
0.30
ADM4073H
0.41
05131-010
SUPPLY CURRENT (mA)
0.55
0
5
10
15
20
25
SUPPLY VOLTAGE (V)
Figure 6. Supply Current vs. Temperature
Figure 9. Total Output Error vs. Supply Voltage (VSENSE = 100 mV)
Rev. 0 | Page 6 of 12
ADM4073
1.0
2.0
VSENSE = 6.25mV
1.5
0.6
1.0
0.4
GAIN ACCURACY (%)
ADM4073F
0.2
0
ADM4073T
–0.2
–0.4
0.5
0
–0.5
–1.0
–0.6
ADM4073H
5
10
15
20
25
30
SUPPLY VOLTAGE (V)
–2.0
–50
25
75
100
125
150
150
1.4
ADM4073F
0.5
1.2
ADM4073H
ADM4073H
0
1.0
VCC – VOH (V)
ADM4073T
–0.5
–1.0
–1.5
0.8
ADM4073F
0.6
0.4
–2.0
ADM4073T
0.2
–2.5
0
5
10
15
20
25
30
COMMON-MODE VOLTAGE (V)
0
–50
05131-012
–3.0
50
Figure 13. Gain Accuracy vs. Temperature
1.0
TOTAL OUTPUT ERROR (%)
0
TEMPERATURE (°C)
Figure 10. Total Output Error vs. Supply Voltage (VSENSE = 6.25 mV)
0
50
100
TEMPERATURE (°C)
Figure 11. Total Output Error vs. Common-Mode Voltage
Figure 14. O/P High Voltage (VCC − VOH) vs. Temperature
70
0.10
ADM4073F
0.08
60
0.06
VCC = 28V
0.04
0.02
50
VCC = 12V
PSRR (dB)
TOTAL OUTPUT ERROR (%)
–25
05131-014
0
05131-011
–1.0
05131-015
–1.5
–0.8
0
–0.02
–0.04
40
ADM4073T
30
20
–0.06
–0.08
0
50
100
TEMPERATURE (°C)
150
0
0.1
05131-013
–0.10
–50
ADM4073H
10
1
10
100
FREQUENCY (kHz)
Figure 15. PSRR vs. Frequency
Figure 12. Total Output Error vs. Temperature
Rev. 0 | Page 7 of 12
1000
10000
05131-016
TOTAL OUTPUT ERROR (%)
0.8
ADM4073
45
ADM4073H
100mV
40
ADM4073F
35
GAIN (dB)
30
VSENSE
2.5mV/DIV
ADM4073T
95mV
25
20
10V
15
10
OUT
250mV/DIV
100
1000
10000
1µs/DIV
Figure 19. ADM4073H Small Signal Transient Response
Figure 16. Small Signal Gain vs. Frequency
100mV
VSENSE
2.5mV/DIV
100mV
VSENSE
45mV/DIV
95mV
6.25mV
2V
OUT
50mV/DIV
2V
OUT
0.9V/DIV
05131-018
1.9V
1µs/DIV
0.120V
1µs/DIV
Figure 17. ADM4073T Small Signal Transient Response
Figure 20. ADM4073T Large Signal Transient Response
100mV
VSENSE
2.5mV/DIV
100mV
VSENSE
45mV/DIV
95mV
6.25mV
5V
OUT
125mV/DIV
5V
OUT
2.35V/DIV
05131-019
4.75V
1µs/DIV
05131-021
10
FREQUENCY (kHz)
Figure 18. ADM4073F Small Signal Transient Response
0.3V
1µs/DIV
Figure 21. ADM4073F Large Signal Transient Response
Rev. 0 | Page 8 of 12
05131-022
1
05131-017
0
0.1
9.5V
05131-020
5
ADM4073
VCC = 0V TO 4V
100mV
6.25mV
VCC
2V/DIV
0V
10V
OUT
4.7V/DIV
2V
OUT
1V/DIV
05131-023
0.6V
1µs/DIV
Figure 22. ADM4073H Large Signal Transient Response
250mV
50mV
VOH
OUT
600mV/DIV
05131-024
1V
1µs/DIV
1µs/DIV
Figure 24. ADM4073T Start-Up Delay
VCC = 3V
VSENSE
100mV/DIV
0V
Figure 23. ADM4073T Overdrive Response
Rev. 0 | Page 9 of 12
05131-025
VSENSE
45mV/DIV
4V
ADM4073
THEORY OF OPERATION
The current from the source flows through RSENSE, which
generates a voltage drop, VSENSE, 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 VSENSE/RG1 to the output current mirror. This
current is then multiplied by a gain factor b in the output stage
current mirror and flows through RGD to generate VOUT.
Therefore, VOUT is related to VSENSE by the ratio of R G1 to RGD and
the current gain b.
VOUT = AV × VSENSE
where:
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 I2R
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.
AV = RGD/R G1 × b
where:
RSENSE
INPUT
AV = 20 V/V (for ADM4073T).
AV = 50 V/V (for ADM4073H).
AV = 100 V/V (for ADM4073F).
RS+
ILOAD
VCC
OUT
ADM4073
GND
RG2
05131-004
RG1
OUTPUT
RS–
0.1µF
IRG1
VCC
0.1µF
VOUT
RS–
RS+
3V TO 28V
3V TO 28V
RSENSE
2V TO 28V
COPPER PCB TRACE
Figure 26. Using PCB Trace for Current Sensing
AV
OUTPUT (OUT)
ADM4073
VOUT
CURRENT
MIRROR
RGD = 12kΩ
GND
05131-003
IRGD
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.
Figure 25. Functional Block Diagram
The percent error introduced by output loading is determined
with the following formula:
RSENSE
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).
% Error = 100 ((RLOAD / ROUT _ INT + RSENSE ) − 1)
where:
RLOAD is the external load applied to OUT.
ROUT_INT is the internal output resistance (12 kΩ).
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:
RSENSE = 100 mV/10 A
RSENSE = 10 mΩ
VOUT = (ILOAD × RSENSE) × AV
Rev. 0 | Page 10 of 12
ADM4073
OUTLINE DIMENSIONS
2.90 BSC
6
5
4
1
2
3
2.80 BSC
1.60 BSC
PIN 1
INDICATOR
0.95 BSC
1.30
1.15
0.90
1.90
BSC
1.45 MAX
0.15 MAX
0.50
0.30
0.22
0.08
SEATING
PLANE
10°
4°
0°
0.60
0.45
0.30
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
ADM4073TWRJZ-REEL7 1
ADM4073FWRJZ-REEL71
ADM4073HWRJZ-REEL71
1
Gain
20
50
100
Temperature Range
−40°C to +125°C
−40°C to +125°C
−40°C to +125°C
Package Description
6-Lead SOT-23
6-Lead SOT-23
6-Lead SOT-23
Z = Pb-free part.
Rev. 0 | Page 11 of 12
Package Option
RJ-6
RJ-6
RJ-6
Branding
M2E
M2C
M2D
ADM4073
NOTES
©2006 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective owners.
D05131-0-7/06(0)
Rev. 0 | Page 12 of 12
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