MAX4372T/F/H
Low-Cost, UCSP/SOT23, Micropower, High-Side
Current-Sense Amplifier with Voltage Output
General Description
The MAX4372 low-cost, precision, high-side currentsense amplifier is available in a tiny, space-saving
SOT23 5-pin package. Offered in three gain versions
(T = 20V/V, F = 50V/V, and H = 100V/V), this device operates from a single 2.7V to 28V supply and consumes only
30μA. It features a voltage output that eliminates the need
for gain-setting resistors and is ideal for today’s notebook
computers, cell phones, and other systems where battery/
DC current monitoring is critical.
High-side current monitoring is especially useful in battery-powered systems since it does not interfere with the
ground path of the battery charger. The input commonmode range of 0 to 28V is independent of the supply voltage and ensures that the current-sense feedback remains
viable even when connected to a 2-cell battery pack in
deep discharge.
The user can set the full-scale current reading by choosing the device (T, F, or H) with the desired voltage gain
and selecting the appropriate external sense resistor.
This capability offers a high level of integration and flexibility, resulting in a simple and compact current-sense
solution. For higher bandwidth applications, refer to the
MAX4173T/F/H data sheet.
Applications
●●
●●
●●
●●
●●
●●
●●
Power-Management Systems
General-System/Board-Level Current Monitoring
Notebook Computers
Portable/Battery-Powered Systems
Smart-Battery Packs/Chargers
Cell Phones
Precision-Current Sources
Features
●● Low-Cost, Compact Current-Sense Solution
●● 30μA Supply Current
●● 2.7V to 28V Operating Supply
●● 0.18% Full-Scale Accuracy
●● 0.3mV Input Offset Voltage
●● Low 1.5Ω Output Impedance
●● Three Gain Versions Available
• 20V/V (MAX4372T)
• 50V/V (MAX4372F)
• 100V/V (MAX4372H)
●● High Accuracy +2V to +28V Common-Mode Range,
Functional Down to 0V, Independent of Supply
Voltage
●● Available in a Space-Saving 5-Pin SOT23 Package
and 3 x 2 UCSP™ (1mm x 1.5mm) Package
Ordering Information
PART
TEMP
RANGE
MAX4372TEUK+T
-40°C to +85°C
5 SOT23
MAX4372TESA+
-40°C to +85°C
8 SO
MAX4372TEBT+T
-40°C to +85°C
3 x 2 UCSP
GND
OUT
VCC
2
5
A
MAX4372T
MAX4372F
MAX4372H
3
B
4
1
2
3
VCC
GND
OUT
RS-
RS+
MAX4372T
MAX4372F
RS+ MAX4372H RS-
UCSP
SOT23
Pin Configurations continued at end of datasheet.
19-1548; Rev 5; 5/11
ADIU
—
ACX
Ordering Information appears at end of data sheet.
Typical Operating Circuit
ILOAD
GND
TOP VIEW
(BUMPS ON BOTTOM)
1
TOP
MARK
+Denotes lead(Pb)-free/RoHS-compliant package.
T = Tape and reel.
*Note: Gain values are as follows: 20V/V for the T version,
50V/V for the F version, and 100V/V for the H version.
Pin Configurations
TOP VIEW
PINPACKAGE
A/D
CONVERTER
VCC
+2.7V TO +28V
0.1µF
RS-
MAX4372T
MAX4372F
OUT MAX4372H
VCC
RSENSE
VSENSE
LOAD/
BATTERY
RS+
VIN
0 TO 28V
UCSP is a trademark of Maxim Integrated Products, Inc.
MAX4372T/F/H
Low-Cost, UCSP/SOT23, Micropower, High-Side
Current-Sense Amplifier with Voltage Output
Absolute Maximum Ratings
VCC, RS+, RS- to GND..........................................-0.3V to +30V
OUT to GND...........................................................-0.3V to +15V
Differential Input Voltage (VRS+ - VRS-)..............................±0.3V
Current into Any Pin..........................................................±10mA
Continuous Power Dissipation (TA = +70°C)
5-Pin SOT23 (derate 3.9mW/°C above +70°C)........312.6mW
8-Pin SO (derate 7.4mW/°C above +70°C)...............588.2mW
3 x 2 UCSP (derate 3.4mW/°C above +70°C)..........273.2mW
Operating Temperature Range............................ -40°C to +85°C
Storage Temperature Range............................. -65°C to +150°C
Lead Temperature (soldering, 10s).................................. +300°C
Soldering Temperature (reflow)........................................+260°C
Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these
or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to absolute maximum rating conditions for extended periods may affect
device reliability.
Electrical Characteristics
(VRS+ = 0 to 28V, VCC = 2.7V to 28V, VSENSE = 0V, RLOAD = 1MΩ, TA = TMIN to TMAX, unless otherwise noted. Typical values are
at TA = +25°C.) (Note 1)
PARAMETER
Operating Voltage Range
(Note 2)
SYMBOL
CONDITIONS
MIN
TYP
MAX
UNITS
VCC
2.7
28
V
Common-Mode Input Range
(Note 3)
VCMR
0
28
V
Common-Mode Rejection
CMR
Supply Current
Leakage Current
ICC
IRS+, IRSIRS+
Input Bias Current
IRSFull-Scale Sense Voltage
(Note 4)
Input Offset Voltage
(Note 5)
Full-Scale Accuracy
(Note 5)
VSENSE
VOS
VRS+ > 2V
85
VRS+ > 2V, VSENSE = 5mV
VCC = 0V, VRS+ = 28V
dB
30
60
μA
0.05
1.2
μA
VRS+ > 2V
0
1
VRS+ ≤ 2V
-25
+2
VRS+ > 2V
0
2
VRS+ ≤ 2V
-50
+2
Gain = 20V/V or 50V/V
150
Gain = 100V/V
100
MAX4372_ESA
0.3
±0.8
MAX4372_EUK, _EBT
0.3
±1.3
TA = TMIN to TMAX
VCC = VRS+ = 12V
MAX4372_ESA
±1.1
MAX4372_EUK, _EBT
±1.9
±0.18
VSENSE = 100mV, VCC = 12V,
VRS+ = 12V (Note 7)
Total OUT Voltage Error
(Note 6)
www.maximintegrated.com
mV
TA = +25°C
VCC = VRS+ = 12V
VSENSE = 100mV, VCC = 12V,
VRS+ = 12V, TA = +25°C (Note 7)
μA
mV
±3
±6
VSENSE = 100mV, VCC = 28V,
VRS+ = 28V (Note 7)
±0.15
±7
VSENSE = 100mV, VCC = 12V,
VRS+ = 0.1V (Note 7)
±1
±28
VSENSE = 6.25mV, VCC = 12V,
VRS+ = 12V (Note 8)
±0.15
%
Maxim Integrated │ 2
MAX4372T/F/H
Low-Cost, UCSP/SOT23, Micropower, High-Side
Current-Sense Amplifier with Voltage Output
Electrical Characteristics (continued)
(VRS+ = 0 to 28V, VCC = 2.7V to 28V, VSENSE = 0V, RLOAD = 1MΩ, TA = TMIN to TMAX, unless otherwise noted. Typical values are
at TA = +25°C.) (Note 1)
PARAMETER
SYMBOL
CONDITIONS
MIN
TYP
MAX
OUT Low Voltage
(MAX4372T, MAX4372F)
VOL
VCC = 2.7V,
VSENSE = -10mV,
VRS+ = 28V
IOUT = 10μA
2.6
IOUT = 100μA
9
OUT Low Voltage
(MAX4372H)
VOL
VCC = 2.7V,
VSENSE = -10mV,
VRS+ = 12V
IOUT = 10μA
2.6
IOUT = 100μA
9
65
OUT High Voltage
VCC - VOH
0.1
0.25
-3dB Bandwidth
BW
Gain
VCC = 2.7V, IOUT = -500μA,
VSENSE = 250mV, VRS+ = 28V
VRS+ = 12V,
VCC = 12V,
CLOAD = 10pF
65
VSENSE = 20mV,
gain = 20V/V
275
VSENSE = 20mV,
gain = 50V/V
200
VSENSE = 20mV,
gain = 100V/V
110
VSENSE = 6.25mV
50
MAX4372T
20
MAX4372F
50
MAX4372H
100
Gain Accuracy
VSENSE = 20mV
to 100mV, VRS+ = 12V
TA = +25°C
OUT Settling Time to 1% of
Final Value
Gain = 20V/V,
VCC = 12V,
VRS+ = 12V,
CLOAD = 10pF
VSENSE = 6.25mV to
100mV
20
VSENSE = 100mV to
6.25mV
20
Capacitive-Load Stability
No sustained oscillations
OUT Output Resistance
ROUT
VSENSE = 100mV
Power-Supply Rejection
PSR
VOUT = 2V, VRS+ > 2V
UNITS
mV
mV
V
kHz
V/V
±0.25
TA = -40°C to +85°C
±2.5
±5.5
%
µs
75
1000
pF
1.5
Ω
85
dB
Power-Up Time to 1% of
Final Value
VCC = 12V, VRS+ = 12V,
VSENSE = 100mV, CLOAD = 10pF
0.5
ms
Saturation Recovery Time
(Note 9)
VCC = 12V, VRS+ = 12V, CLOAD = 10pF
0.1
ms
Note 1: All devices are 100% production tested at TA = +25°C. All temperature limits are guaranteed by design.
Note 2: Guaranteed by PSR test.
Note 3: Guaranteed by OUT voltage error test.
Note 4: Output voltage is internally clamped not to exceed 12V.
Note 5: VOS is extrapolated from the gain accuracy tests.
Note 6: Total OUT voltage error is the sum of gain and offset voltage errors.
Note 7: Measured at IOUT = -500μA (RLOAD = 4kΩ for gain = 20V/V, RLOAD = 10kΩ for gain = 50V/V, RLOAD = 20kΩ for gain = 100V/V).
Note 8: 6.25mV = 1/16 of 100mV full-scale voltage (C/16).
Note 9: The device does not reverse phase when overdriven.
www.maximintegrated.com
Maxim Integrated │ 3
MAX4372T/F/H
Low-Cost, UCSP/SOT23, Micropower, High-Side
Current-Sense Amplifier with Voltage Output
Typical Operating Characteristics
(VCC = 12V, VRS+ = 12V, VSENSE = 100mV, TA = +25°C, unless otherwise noted.)
AV = +20V/V
27.5
8
12
16
20
0
28
-15
10
35
60
28.0
85
MAX4372 toc03
AV = +20V/V
29.0
VSENSE = 5mV
0
4
8
12
16
20
24
TOTAL OUTPUT ERROR vs. VSENSE
POWER-SUPPLY REJECTION
vs. FREQUENCY
1.0
OUTPUT ERROR (%)
-0.6
-40
AV = +50V/V
AV = +20V/V
0
-45
-50
-55
AV = +100V/V
0.5
28
MAX4372T toc06
1.5
-0.8
-60
-65
-70
-75
-0.5
-80
-1.0
-85
15
20
25
30
0
50
1.0
0.8
G = +50V/V
G = +100V/V
0
5
10
20
25
COMMON-MODE VOLTAGE (V)
www.maximintegrated.com
100
1k
AV = +20V/V
-0.1
-0.2
AV = +50V/V
-0.3
30
-0.5
-0.6
-0.7
-1.0
100k
TOTAL OUTPUT ERROR vs. TEMPERATURE
AV = +100V/V
-0.4
10k
FREQUENCY (Hz)
-0.9
15
-90
300
-0.8
G = +20V/V
0.2
250
GAIN ACCURACY vs. TEMPERATURE
GAIN ACCURACY (%)
1.2
0.4
200
0
MAX4372T toc07
1.4
0.6
150
VSENSE (mV)
TOTAL OUTPUT ERROR
vs. COMMON-MODE VOLTAGE
1.6
100
1.0
MAX4372T toc09
10
0.8
TOTAL OUTPUT ERROR (%)
5
MAX4372T toc08
0
-1.0
SUPPLY VOLTAGE (V)
OUTPUT ERROR (%)
29.5
TOTAL OUTPUT ERROR
vs. SUPPLY VOLTAGE
-0.4
0
AV = +50V/V
COMMON-MODE VOLTAGE (V)
-0.2
-1.2
30.0
28.5
VSENSE = 5mV
-40
30.5
TEMPERATURE (°C)
G = +50V/V
G = +20V/V
0
10
31.0
SUPPLY VOLTAGE (V)
0.4
OUTPUT ERROR (%)
24
G = +100V/V
0.2
15
PSR (dB)
0.6
20
MAX4372T toc05
4
25
5
VSENSE = 5mV
0
30
AV = +100V/V
31.5
SUPPLY CURRENT (µA)
AV = +50V/V
30.0
35
SUPPLY CURRENT (µA)
AV = +100V/V
32.0
MAX4372T toc02
MAX4372 toc01
32.5
25.0
40
MAX4372 toc04
SUPPLY CURRENT (µA)
35.0
SUPPLY CURRENT
vs. COMMON-MODE VOLTAGE
SUPPLY CURRENT vs. TEMPERATURE
SUPPLY CURRENT vs. SUPPLY VOLTAGE
0.6
0.4
AV = +50V/V
0.2
0
-0.2
AV = +100V/V
AV = +20V/V
-0.4
-0.6
-0.8
-40
-15
10
35
TEMPERATURE (°C)
60
85
-1.0
-40
-15
10
35
60
85
TEMPERATURE (°C)
Maxim Integrated │ 4
MAX4372T/F/H
Low-Cost, UCSP/SOT23, Micropower, High-Side
Current-Sense Amplifier with Voltage Output
Typical Operating Characteristics (continued)
(VCC = 12V, VRS+ = 12V, VSENSE = 100mV, TA = +25°C, unless otherwise noted.)
MAX4372T
SMALL-SIGNAL TRANSIENT RESPONSE
MAX4372F
SMALL-SIGNAL TRANSIENT RESPONSE
MAX4372T toc10
MAX4372H
SMALL-SIGNAL TRANSIENT RESPONSE
MAX4372T toc11
30mV
MAX4372T toc12
30mV VSENSE
30mV
10mV
10mV
10mV
600mV
1.5V
3V
VSENSE
VSENSE
VOUT
VOUT
VOUT
200mV
1V
0.5V
20µs/div
20µs/div
20µs/div
MAX4372T
LARGE-SIGNAL TRANSIENT RESPONSE
MAX4372F
LARGE-SIGNAL TRANSIENT RESPONSE
MAX4372T toc13
MAX4372T toc14
150mV
VSENSE
150mV
VSENSE
50mV
50mV
3V
7.5V
VOUT
VOUT
1V
2.5V
20µs/div
20µs/div
MAX4372T toc15
3
SMALL-SIGNAL GAIN vs. FREQUENCY
MAX4372T toc16
MAX4372H
LARGE-SIGNAL TRANSIENT RESPONSE
2
1
100mV
VSENSE
G = 50V/V
0
10V
GAIN (dB)
0
G = 20V/V
-1
-2
-3
G = 100V/V
-4
VOUT
-5
-6
0
20µs/div
www.maximintegrated.com
-7
-8
VSENSE = 20mV
1k
10k
100k
1M
FREQUENCY (Hz)
Maxim Integrated │ 5
MAX4372T/F/H
Low-Cost, UCSP/SOT23, Micropower, High-Side
Current-Sense Amplifier with Voltage Output
Pin/Bump Description
PIN
BUMP
NAME
FUNCTION
SOT23
SO
UCSP
1
3
A2
GND
Ground
2
4
A3
OUT
Output Voltage. VOUT is proportional to the magnitude of VSENSE
(VRS+ - VRS-).
3
1
A1
VCC
Supply Voltage. Use at least a 0.1μF capacitor to decouple VCC from fast
transients.
4
8
B1
RS+
Power Connection to the External Sense Resistor
5
6
B3
RS-
Load-Side Connection to the External Sense Resistor
—
2, 5, 7
—
N.C.
No Connection. Not internally connected.
Detailed Description
The MAX4372 high-side current-sense amplifier features
a 0 to 28V input common-mode range that is independent of supply voltage. This feature allows the monitoring
of current flow out of a battery in deep discharge, and
also enables high-side current sensing at voltages far in
excess of the supply voltage (VCC).
Current flows through the sense resistor, generating a
sense voltage (Figure 1. Functional Diagram). Since
A1’s inverting input is high impedance, the voltage on
the negative terminal equals VIN - VSENSE. A1 forces its
positive terminal to match its negative terminal; therefore,
the voltage across RG1 (VIN - V1-) equals VSENSE. This
creates a current to flow through RG1 equal to VSENSE/
RG1. The transistor and current mirror amplify the current
by a factor of β. This makes the current flowing out of the
current mirror equal to:
IM = β VSENSE/RG1
A2’s positive terminal presents high impedance, so this
current flows through RGD, with the following result:
V2+ = RGD β x VSENSE/RG1
R1 and R2 set the closed-loop gain for A2, which amplifies V2+, yielding:
VOUT = RGD x β x VSENSE/RG1 (1 + R2/R1)
The gain of the device equals:
VOUT
VSENSE
= RGD x β (1 + R2 /R1) /R G1
Applications Information
Recommended Component Values
The MAX4372 operates over a wide variety of current
ranges with different sense resistors. Table 1 lists common resistor values for typical operation of the MAX4372.
www.maximintegrated.com
RG1
100kΩ
2.7V
TO
28V
VCC
A1
V1+
RG2
100kΩ
VIN
0 TO 28V
RS+
RSENSE
RS-
V1CURRENT
MIRROR
RGD
IM
MAX4372T
MAX4372F
MAX4372H
VSENSE
ILOAD
TO
LOAD
V2+
OUT
A2
V2R2
R1
GND
Figure 1. Functional Diagram
Choosing RSENSE
Given the gain and maximum load current, select RSENSE
such that VOUT does not exceed VCC - 0.25V or 10V. To
measure lower currents more accurately, use a high value
for RSENSE. A higher value develops a higher sense voltage, which overcomes offset voltage errors of the internal
current amplifier.
In applications monitoring very high current, ensure
RSENSE is able to dissipate its own I2R losses. If the
resistor’s rated power dissipation is exceeded, its value
may drift or it may fail altogether, causing a differential
voltage across the terminals in excess of the absolute
maximum ratings.
Maxim Integrated │ 6
MAX4372T/F/H
Low-Cost, UCSP/SOT23, Micropower, High-Side
Current-Sense Amplifier with Voltage Output
Table 1. Recommended Component Values
FULL-SCALE LOAD
CURRENT,
ILOAD (A)
0.1
1
5
10
CURRENT-SENSE
RESISTOR,
RSENSE (mΩ)
1000
100
20
10
GAIN
(V/V)
FULL-SCALE OUTPUT
VOLTAGE (FULL-SCALE
VSENSE = 100mV),
VOUT (V)
20
2.0
50
5.0
100
10.0
20
2.0
50
5.0
100
10.0
20
2.0
50
5.0
100
10.0
20
2.0
50
5.0
100
10.0
Using a PC Board Trace as RSENSE
If the cost of RSENSE is an issue and accuracy is not critical, use the alternative solution shown in Figure 2. This
solution uses copper PC board traces to create a sense
resistor. The resistivity of a 0.1in wide trace of 2oz copper
is about 30mΩ/ft. The resistance temperature coefficient
of copper is fairly high (approximately 0.4%/°C), so systems that experience a wide temperature variance must
compensate for this effect. In addition, self-heating introduces a nonlinearity error. Do not exceed the maximum
power dissipation of the copper trace.
For example, the MAX4372T (with a maximum load current of 10A and an RSENSE of 5mΩ) creates a full-scale
VSENSE of 50mV that yields a maximum VOUT of 1V.
RSENSE, in this case, requires about 2in of 0.1in wide
copper trace.
UCSP Applications Information
For the latest application details on UCSP construction,
dimensions, tape carrier information, printed circuit board
techniques, bump-pad layout, and recommended reflow
temperature profile, as well as the latest information on
reliability testing results, go to the Maxim’s website at
www.maxim-ic.com/ucsp to find the Application Note:
UCSP—A Wafer-Level Chip-Scale Package.
www.maximintegrated.com
INPUT
0.3in COPPER
LOAD/BATTERY
RSENSE
0.1in COPPER
0.3in COPPER
VSENSE
RS+
VCC
RS-
OUT
2.7V TO 28V
MAX4372T
MAX4372F
MAX4372H
GND
Figure 2. Connections Showing Use of PC Board
Maxim Integrated │ 7
MAX4372T/F/H
Low-Cost, UCSP/SOT23, Micropower, High-Side
Current-Sense Amplifier with Voltage Output
Ordering Information (continued)
PINPACKAGE
Pin Configurations (continued)
PART
TEMP
RANGE
TOP
MARK
MAX4372FEUK+T
-40°C to +85°C
5 SOT23
MAX4372FESA+
-40°C to +85°C
8 SO
MAX4372FEBT+T
-40°C to +85°C
3 x 2 UCSP
ACX
MAX4372HEUK+T
-40°C to +85°C
5 SOT23
ADIW
MAX4372HESA+
-40°C to +85°C
8 SO
MAX4372HEBT+T
-40°C to +85°C
3 x 2 UCSP
ADIV
—
—
ACZ
VCC 1
N.C. 2
GND
3
MAX4372T
MAX4372F
MAX4372H
OUT 4
8
RS+
7
N.C.
6
RS-
5
N.C.
SO
+Denotes lead(Pb)-free/RoHS-compliant package.
T = Tape and reel.
Chip Information
PROCESS: BiCMOS
www.maximintegrated.com
Maxim Integrated │ 8
MAX4372T/F/H
Low-Cost, UCSP/SOT23, Micropower, High-Side
Current-Sense Amplifier with Voltage Output
Package Information
For the latest package outline information and land patterns (footprints), go to www.maximintegrated.com/packages. Note that a “+”,
“#”, or “-” in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing
pertains to the package regardless of RoHS status.
PACKAGE TYPE
PACKAGE CODE
OUTLINE NO.
LAND PATTERN NO.
5 SOT23
U5+1
21-0057
90-0174
8 SO
S8+2
21-0041
90-0096
5 UCSP
B6+2
21-0097
—
Note: MAX4372_EBT uses package code B6-2.
www.maximintegrated.com
Maxim Integrated │ 9
MAX4372T/F/H
Low-Cost, UCSP/SOT23, Micropower, High-Side
Current-Sense Amplifier with Voltage Output
Package Information (continued)
For the latest package outline information and land patterns (footprints), go to www.maximintegrated.com/packages. Note that a “+”,
“#”, or “-” in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing
pertains to the package regardless of RoHS status.
www.maximintegrated.com
Maxim Integrated │ 10
MAX4372T/F/H
Low-Cost, UCSP/SOT23, Micropower, High-Side
Current-Sense Amplifier with Voltage Output
Package Information (continued)
For the latest package outline information and land patterns (footprints), go to www.maximintegrated.com/packages. Note that a “+”,
“#”, or “-” in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing
pertains to the package regardless of RoHS status.
www.maximintegrated.com
Maxim Integrated │ 11
MAX4372T/F/H
Low-Cost, UCSP/SOT23, Micropower, High-Side
Current-Sense Amplifier with Voltage Output
Revision History
REVISION
NUMBER
REVISION
DATE
PAGES
CHANGED
4
7/09
Updated feature in accordance with actual performance of the product
5
5/11
Updated VRST conditions to synchronize with tested material and added
lead-free designation
DESCRIPTION
1
1–3, 8
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim Integrated’s website at www.maximintegrated.com.
Maxim Integrated cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim Integrated product. No circuit patent licenses
are implied. Maxim Integrated reserves the right to change the circuitry and specifications without notice at any time. The parametric values (min and max limits)
shown in the Electrical Characteristics table are guaranteed. Other parametric values quoted in this data sheet are provided for guidance.
Maxim Integrated and the Maxim Integrated logo are trademarks of Maxim Integrated Products, Inc.
© 2011 Maxim Integrated Products, Inc. │ 12
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