General Description
The MAX4372 low-cost, precision, high-side current-
sense 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 oper-
ates 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 bat-
tery-powered systems since it does not interfere with the
ground path of the battery charger. The input common-
mode range of 0 to 28V is independent of the supply volt-
age 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 choos-
ing 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 flex-
ibility, 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 appears at end of data sheet.
UCSP is a trademark of Maxim Integrated Products, Inc.
Pin Configurations continued at end of datasheet.
19-1548; Rev 5; 5/11
+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.
MAX4372T/F/H Low-Cost, UCSP/SOT23, Micropower, High-Side
Current-Sense Amplifier with Voltage Output
Pin Congurations
Typical Operating Circuit
Ordering Information
PART TEMP
RANGE
PIN-
PACKAGE
TOP
MARK
MAX4372TEUK+T -40°C to +85°C 5 SOT23 ADIU
MAX4372TESA+ -40°C to +85°C 8 SO —
MAX4372TEBT+T -40°C to +85°C 3 x 2 UCSP ACX
RS+
1 5 RS-
SOT23
UCSP
TOP VIEW TOP VIEW
(BUMPS ON BOTTOM)
2
3 4
OUT
OUT
VCC
VCC
GND
GND
2 31
A
BRS+ RS-
MAX4372T
MAX4372F
MAX4372H MAX4372T
MAX4372F
MAX4372H
RS-
OUT
A/D
CONVERTER
VCC
VCC
GND
RS+
RSENSE VSENSE
ILOAD
VIN
0 TO 28V
+2.7V TO +28V
0.1µF
MAX4372T
MAX4372F
MAX4372H LOAD/
BATTERY
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
(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)
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Absolute Maximum Ratings
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
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Operating Voltage Range
(Note 2) VCC 2.7 28 V
Common-Mode Input Range
(Note 3) VCMR 0 28 V
Common-Mode Rejection CMR VRS+ > 2V 85 dB
Supply Current ICC VRS+ > 2V, VSENSE = 5mV 30 60 μA
Leakage Current IRS+, IRS- VCC = 0V, VRS+ = 28V 0.05 1.2 μA
Input Bias Current
IRS+
VRS+ > 2V 0 1
μA
VRS+ ≤ 2V -25 +2
IRS-
VRS+ > 2V 0 2
VRS+ ≤ 2V -50 +2
Full-Scale Sense Voltage
(Note 4) VSENSE
Gain = 20V/V or 50V/V 150 mV
Gain = 100V/V 100
Input Offset Voltage
(Note 5) VOS
TA = +25°C
VCC = VRS+ = 12V
MAX4372_ESA 0.3 ±0.8
mV
MAX4372_EUK, _EBT 0.3 ±1.3
TA = TMIN to TMAX
VCC = VRS+ = 12V
MAX4372_ESA ±1.1
MAX4372_EUK, _EBT ±1.9
Full-Scale Accuracy
(Note 5)
VSENSE = 100mV, VCC = 12V,
VRS+ = 12V, TA = +25°C (Note 7) ±0.18 ±3
%
Total OUT Voltage Error
(Note 6)
VSENSE = 100mV, VCC = 12V,
VRS+ = 12V (Note 7) ±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
(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)
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.
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Electrical Characteristics (continued)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
OUT Low Voltage
(MAX4372T, MAX4372F) VOL
VCC = 2.7V,
VSENSE = -10mV,
VRS+ = 28V
IOUT = 10μA 2.6
mV
IOUT = 100μA 9 65
OUT Low Voltage
(MAX4372H) VOL
VCC = 2.7V,
VSENSE = -10mV,
VRS+ = 12V
IOUT = 10μA 2.6
mV
IOUT = 100μA 9 65
OUT High Voltage VCC - VOH
VCC = 2.7V, IOUT = -500μA,
VSENSE = 250mV, VRS+ = 28V 0.1 0.25 V
-3dB Bandwidth BW
VRS+ = 12V,
VCC = 12V,
CLOAD = 10pF
VSENSE = 20mV,
gain = 20V/V 275
kHz
VSENSE = 20mV,
gain = 50V/V 200
VSENSE = 20mV,
gain = 100V/V 110
VSENSE = 6.25mV 50
Gain
MAX4372T 20
V/VMAX4372F 50
MAX4372H 100
Gain Accuracy VSENSE = 20mV
to 100mV, VRS+
= 12V
TA = +25°C ±0.25 ±2.5 %
TA = -40°C to +85°C ±5.5
OUT Settling Time to 1% of
Final Value
Gain = 20V/V,
VCC = 12V,
VRS+ = 12V,
CLOAD = 10pF
VSENSE = 6.25mV to
100mV 20
µs
VSENSE = 100mV to
6.25mV 20
Capacitive-Load Stability No sustained oscillations 1000 pF
OUT Output Resistance ROUT VSENSE = 100mV 1.5 Ω
Power-Supply Rejection PSR VOUT = 2V, VRS+ > 2V 75 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
(VCC = 12V, VRS+ = 12V, VSENSE = 100mV, TA = +25°C, unless otherwise noted.)
MAX4372T/F/H Low-Cost, UCSP/SOT23, Micropower, High-Side
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Typical Operating Characteristics
25.0
27.5
30.0
32.5
35.0
SUPPLY CURRENT vs. SUPPLY VOLTAGE
MAX4372 toc01
SUPPLY VOLTAGE (V)
SUPPLY CURRENT (µA)
0 12 164 8 20 24 28
AV = +100V/V
AV = +50V/V
AV = +20V/V
VSENSE = 5mV
-1.2
-0.8
-1.0
-0.2
-0.4
-0.6
0.4
0.2
0
0.6
0 105 15 20 25 30
TOTAL OUTPUT ERROR
vs. SUPPLY VOLTAGE
MAX4372 toc04
SUPPLY VOLTAGE (V)
OUTPUT ERROR (%)
G = +100V/V
G = +50V/V
G = +20V/V
0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
0 105 15 20 25 30
TOTAL OUTPUT ERROR
vs. COMMON-MODE VOLTAGE
MAX4372T toc07
COMMON-MODE VOLTAGE (V)
OUTPUT ERROR (%)
G = +100V/V
G = +20V/V
G = +50V/V
0
5
10
15
20
25
30
35
40
-40 10 60-15 35 85
SUPPLY CURRENT vs. TEMPERATURE
MAX4372T toc02
TEMPERATURE (°C)
SUPPLY CURRENT (µA)
VSENSE = 5mV
-1.0
-0.5
0.5
0
1.0
1.5
0 10050 150 200 250 300
TOTAL OUTPUT ERROR vs. VSENSE
MAX4372T toc05
VSENSE (mV)
OUTPUT ERROR (%)
AV = +100V/V
AV = +20V/V
AV = +50V/V
-1.0
-0.9
-0.8
-0.7
-0.6
-0.5
-0.4
-0.3
-0.2
-0.1
0
GAIN ACCURACY vs. TEMPERATURE
MAX4372T toc08
TEMPERATURE (°C)
GAIN ACCURACY (%)
-40 10 60-15 35 85
AV = +20V/V
AV = +50V/V
AV = +100V/V
28.0
29.0
28.5
30.0
29.5
31.5
31.0
30.5
32.0
SUPPLY CURRENT
vs. COMMON-MODE VOLTAGE
MAX4372 toc03
COMMON-MODE VOLTAGE (V)
SUPPLY CURRENT (µA)
0 12 164 8 20 24 28
AV = +100V/V
AV = +50V/V
AV = +20V/V
VSENSE = 5mV
-45
-90 100 100k10k1k
POWER-SUPPLY REJECTION
vs. FREQUENCY
-75
-85
-55
-65
-40
-70
-80
-50
-60
MAX4372T toc06
FREQUENCY (Hz)
PSR (dB)
-1.0
-0.8
-0.6
-0.4
-0.2
0
0.2
0.4
0.6
0.8
1.0
-40 10 60-15 35 85
TOTAL OUTPUT ERROR vs. TEMPERATURE
MAX4372T toc09
TEMPERATURE (°C)
TOTAL OUTPUT ERROR (%)
AV = +50V/V
AV = +100V/V
AV = +20V/V
(VCC = 12V, VRS+ = 12V, VSENSE = 100mV, TA = +25°C, unless otherwise noted.)
MAX4372T/F/H Low-Cost, UCSP/SOT23, Micropower, High-Side
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Typical Operating Characteristics (continued)
VOUT
VSENSE
600mV
200mV
30mV
10mV
MAX4372T
SMALL-SIGNAL TRANSIENT RESPONSE
MAX4372T toc10
20µs/div
VOUT
VSENSE
1V
3V
50mV
150mV
MAX4372T
LARGE-SIGNAL TRANSIENT RESPONSE
MAX4372T toc13
20µs/div
VOUT
VSENSE
0
10V
0
100mV
MAX4372H
LARGE-SIGNAL TRANSIENT RESPONSE
20µs/div
MAX4372T toc15
VOUT
VSENSE
2.5V
7.5V
50mV
150mV
MAX4372F
LARGE-SIGNAL TRANSIENT RESPONSE
20µs/div
MAX4372T toc14
3
-8 1k 100k10k 1M
SMALL-SIGNAL GAIN vs. FREQUENCY
-7
MAX4372T toc16
FREQUENCY (Hz)
GAIN (dB)
-6
-5
-4
-3
-2
-1
0
1
2
G = 50V/V
G = 20V/V
G = 100V/V
VSENSE = 20mV
VOUT
VSENSE
1.5V
0.5V
30mV
10mV
MAX4372F
SMALL-SIGNAL TRANSIENT RESPONSE
MAX4372T toc11
20µs/div
VOUT
VSENSE
3V
1V
30mV
10mV
MAX4372H
SMALL-SIGNAL TRANSIENT RESPONSE
MAX4372T toc12
20µs/div
Detailed Description
The MAX4372 high-side current-sense amplifier features
a 0 to 28V input common-mode range that is indepen-
dent 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 ampli-
fies V2+, yielding:
VOUT = RGD x β x VSENSE/RG1 (1 + R2/R1)
The gain of the device equals:
OUT
SEN
G1
SE
RGD x (1 + R2/R1)
V
V/Rβ=
Applications Information
Recommended Component Values
The MAX4372 operates over a wide variety of current
ranges with different sense resistors. Table 1 lists com-
mon resistor values for typical operation of the MAX4372.
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 volt-
age, 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.
Figure 1. Functional Diagram
MAX4372T/F/H Low-Cost, UCSP/SOT23, Micropower, High-Side
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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.
GND
TO
LOAD
VIN
0 TO 28V
2.7V
TO
28V
R1
RGD
RG2
100kΩ
RS+
RS-
RG1
100kΩ
R2
OUT
V2+
V1+
V1-
V2-
VCC RSENSE
ILOAD
IM
VSENSE
CURRENT
MIRROR
A1
A2
MAX4372T
MAX4372F
MAX4372H
Using a PC Board Trace as RSENSE
If the cost of RSENSE is an issue and accuracy is not criti-
cal, 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 sys-
tems that experience a wide temperature variance must
compensate for this effect. In addition, self-heating intro-
duces a nonlinearity error. Do not exceed the maximum
power dissipation of the copper trace.
For example, the MAX4372T (with a maximum load cur-
rent 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.
Figure 2. Connections Showing Use of PC Board
Table 1. Recommended Component Values
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FULL-SCALE LOAD
CURRENT,
ILOAD (A)
CURRENT-SENSE
RESISTOR,
RSENSE (mΩ)
GAIN
(V/V)
FULL-SCALE OUTPUT
VOLTAGE (FULL-SCALE
VSENSE = 100mV),
VOUT (V)
0.1 1000
20 2.0
50 5.0
100 10.0
1 100
20 2.0
50 5.0
100 10.0
5 20
20 2.0
50 5.0
100 10.0
10 10
20 2.0
50 5.0
100 10.0
0.1in COPPER 0.3in COPPER0.3in COPPER
INPUT LOAD/BATTERY
VCC
VSENSE
RSENSE
GND
2.7V TO 28V
RS+
RS- OUT
MAX4372T
MAX4372F
MAX4372H
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Ordering Information (continued) Pin Congurations (continued)
PART TEMP
RANGE
PIN-
PACKAGE
TOP
MARK
MAX4372FEUK+T -40°C to +85°C 5 SOT23 ADIV
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 ACZ
Chip Information
PROCESS: BiCMOS
RS-
N.C.OUT
1
2
8
7
RS+
N.C.N.C.
GND
VCC
SO
3
4
6
5
MAX4372T
MAX4372F
MAX4372H
+Denotes lead(Pb)-free/RoHS-compliant package.
T = Tape and reel.
Note: MAX4372_EBT uses package code B6-2.
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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 —
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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.
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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.
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 specications 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.
MAX4372T/F/H Low-Cost, UCSP/SOT23, Micropower, High-Side
Current-Sense Amplier with Voltage Output
© 2011 Maxim Integrated Products, Inc.
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Revision History
REVISION
NUMBER
REVISION
DATE DESCRIPTION PAGES
CHANGED
4 7/09 Updated feature in accordance with actual performance of the product 1
5 5/11 Updated VRST conditions to synchronize with tested material and added
lead-free designation 1–3, 8
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