General Description
The MAX4073 low-cost, high-side current-sense ampli-
fier features a voltage output that eliminates the need
for gain-setting resistors making it ideal for cell phones,
notebook computers, PDAs, and other systems where
current monitoring is crucial. High-side current moni-
toring does not interfere with the ground path of the
battery charger making the MAX4073 particularly useful
in battery-powered systems. The input common-mode
range of +2V to +28V is independent of the supply volt-
age. The MAX4073’s wide 1.8MHz bandwidth makes it
suitable for use inside battery-charger control loops.
The combination of three gain versions and a selec-
table external-sense resistor sets the full-scale current
reading. The MAX4073 offers a high level of integra-
tion, resulting in a simple and compact current-sense
solution.
The MAX4073 operates from a +3V to +28V single sup-
ply and draws only 0.5mA of supply current. This
device is specified over the automotive operating tem-
perature range (-40°C to +125°C) and is available in a
space-saving 5-pin SC70 package (half the size of the
SOT23).
For a similar device in a 6-pin SOT23 with a wider com-
mon-mode voltage range (0 to +28V), see the
MAX4173 data sheet.
Applications
Cell Phones
Notebook Computers
Portable/Battery-Powered Systems
Smart Battery Packs/Chargers
PDAs
Power Management Systems
PA Bias Control
General System/Board-Level Current Monitoring
Precision Current Sources
Features
♦Low-Cost, Compact, Current-Sense Solution
♦Three Gain Versions Available
+20V/V (MAX4073T)
+50V/V (MAX4073F)
+100V/V (MAX4073H)
♦±1.0% Full-Scale Accuracy
♦500µA Supply Current
♦Wide 1.8MHz Bandwidth
♦+3V to +28V Operating Supply
♦Wide +2V to +28V Common-Mode Range
Independent of Supply Voltage
♦Automotive Temperature Range (-40°C to +125°C)
♦Available in Space-Saving 5-Pin SC70 Package
MAX4073T/F/H
Low-Cost, SC70, Voltage-Output,
High-Side Current-Sense Amplifier
Typical Operating Circuit
19-2048; Rev 1; 8/12
For pricing, delivery, and ordering information, please contact Maxim Direct
at 1-888-629-4642, or visit Maxim’s website at www.maximintegrated.com.
Ordering Information
Pin Configurations appear at end of data sheet.
PART TEMP. RANGE PIN-PACKAGE GAIN (V/V) TOP MARK
MAX4073TAXK+T -40°C to +125°C 5 SC70 20 ACM
MAX4073TAUT+T -40°C to +125°C 6 SOT23 20 AAUE
MAX4073FAXK+T -40°C to +125°C 5 SC70 50 ACN
MAX4073FAUT+T -40°C to +125°C 6 SOT23 50 AAUF
MAX4073HAXK+T -40°C to +125°C 5 SC70 100 ACO
MAX4073HAUT+T -40°C to +125°C 6 SOT23 100 AAUG
+Denotes lead(Pb)-free/RoHS-compliant package.
MAX4073T/F/H
RSENSE
ILOAD
+2V TO +28V VSENSE
VCC
OUT
VIN
GND
RS+
+3V TO +28V
0.1µF
RS-
LOAD/
BATTERY
LOW-COST
SWITCHING
REGULATOR
MAX4073T/F/H
Low-Cost, SC70, Voltage-Output,
High-Side Current-Sense Amplifier
2Maxim Integrated
ABSOLUTE MAXIMUM RATINGS
ELECTRICAL CHARACTERISTICS
(VRS+ = +2V to +28V, VSENSE = (VRS+ - VRS-) = 0, VCC = +3V to +28V, TA= TMIN to TMAX, unless otherwise noted. Typical values are
at TA= +25°C.) (Note 1)
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.
VCC to GND............................................................-0.3V to +30V
RS+, RS- to GND....................................................-0.3V to +30V
OUT to GND ...............................................-0.3V to (VCC + 0.3V)
Output Short-Circuit to GND ......................................Continuous
Differential Input Voltage (VRS+ - VRS-) .................................±5V
Current Into Any Pin..........................................................±20mA
Continuous Power Dissipation (TA= +70°C)
5-Pin SC70 (derate 2.27mW/°C above +70°C)............200mW
6-Pin SOT23 (derate 8.7mW/°C above +70°C)............696mW
Operating Temperature Range .........................-40°C to +125°C
Junction Temperature......................................................+150°C
Storage Temperature Range .............................-65°C to +150°C
Lead Temperature (soldering, 10s) .................................+300°C
Soldering Temperature ....................................................+260°C
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
Operating Voltage Range VCC (Note 2) 3 28 V
Common-Mode Input Range VCMR (Note 3) 2 28 V
Common-Mode Rejection CMR VSENSE = 100mV, VCC = 12V 90 dB
Supply Current ICC VCC = 28V 0.5 1.2 mA
Leakage Current IRS+/IRS- VCC = 0V, VRS+ = 28V 0.05 1 µA
IRS+ 20 60
Input Bias Current IRS- 40 120 µA
Full-Scale Sense Voltage VSENSE VSENSE = (VRS+ - VRS-) 150 mV
VSENSE = 100mV, VCC = 12V, VRS+ = 2V ±1.0
VSENSE = 100mV, VCC = 12V,
VRS+ = 12V, TA = +25oC±1.0 ±5.0
VSENSE = 100mV, VCC = 12V,
VRS+ = 12V, TA = TMIN to TMAX ±7.0
VSENSE = 100mV, VCC = 28V,
VRS+ = 28V, TA = +25oC±1.0 ±5.0
VSENSE = 100mV, VCC = 28V,
VRS+ = 28V, TA = TMIN to TMAX ±8.5
Total OUT Voltage Error (Note 4)
VSENSE = 6.25mV (Note 5); VCC = 12V,
VRS+ = 12V ±7.5
%
Extrapolated Input Offset Voltage VOS VCC = VRS+ = 12V, VSENSE > 10mV 1.0 mV
MAX4073T, VCC = 3V
MAX4073F, VCC = 7.5VOUT High Voltage (VCC - VOH)VSENSE =
150mV
MAX4073H, VCC = 15V
0.8 1.2 V
MAX4073T/F/H
Low-Cost, SC70, Voltage-Output,
High-Side Current-Sense Amplifier
3
Maxim Integrated
ELECTRICAL CHARACTERISTICS (continued)
(VRS+ = +2V to +28V, VSENSE = (VRS+ - VRS-) = 0, VCC = +3V to +28V, TA= TMIN to TMAX, unless otherwise noted. Typical values are
at TA= +25°C.) (Note 1)
PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS
MAX4073T,
VSENSE = 100mV 1.8
MAX4073F,
VSENSE = 100mV 1.7
MAX4073H,
VSENSE = 100mV 1.6
MHz
Bandwidth BW
VCC = 12V,
VRS+ = 12V,
CLOAD = 5pF
MAX4073T/F/H
VSENSE = 6.25mV
(
Note 5
)
600 kHz
MAX4073T 20
MAX4073F 50Gain AV
MAX4073H 100
V/V
TA = +25°C ±1.0 ±4.5
VCC = 12V,
VRS+ = 12V,
VSENSE = 10mV
to 150mV,
MAX4073T/F TA = TMIN to TMAX ±6.5
TA = +25°C ±1.0 ±4.5
Gain Accuracy ∆AV
VCC = 12V,
VRS+ = 12V,
VSENSE = 10mV
to 100mV,
MAX4073H
TA = TMIN to TMAX ±6.5
%
VSENSE = 6.25mV to
100mV 400
OUT Settling Time to 1% of Final
Value
VCC = 12V
VRS+ = 12V
CLOAD = 5pF VSENSE = 100mV to
6.25mV 800
ns
Output Resistance ROUT 12 kΩ
VSENSE = 60mV, MAX4073T 70 78
VSENSE = 24mV, MAX4073F 70 85Power-Supply Rejection Ratio PSRR V
C C = 3V to 28V
VSENSE = 12mV, MAX4073H 70 90
dB
Power-Up Time (Note 6) CLOAD = 5pF, VSENSE = 100mV 5 µs
Saturation Recovery Time
(Note 7)
VCC = 12V, VRS+ = 12V,
CLOAD = 5pF 5µs
Note 1: All devices are 100% production tested at TA = +25°C. All temperature limits are guaranteed by design.
Note 2: Inferred from PSRR test.
Note 3: Inferred from OUT Voltage Error test.
Note 4: Total OUT Voltage Error is the sum of the gain and offset errors.
Note 5: 6.25mV = 1/16 of 100mV full-scale sense voltage.
Note 6: Output settles to within 1% of final value.
Note 7: The device will not experience phase reversal when overdriven.
MAX4073T/F/H
Low-Cost, SC70, Voltage-Output,
High-Side Current-Sense Amplifier
4Maxim Integrated
0.43
0.46
0.45
0.44
0.47
0.48
0.49
0.50
0.51
0.52
0.53
0105 15202530
SUPPLY CURRENT vs.
SUPPLY VOLTAGE
MAX4073 toc01
SUPPLY VOLTAGE (V)
SUPPLY CURRENT (mA)
VSENSE = 6.25mV
MAX4073H
MAX4073F
MAX4073T
0.5
0.8
0.7
0.6
0.9
1.0
1.1
1.2
1.3
1.4
1.5
0105 15202530
SUPPLY CURRENT vs.
SUPPLY VOLTAGE
MAX4073 toc02
SUPPLY VOLTAGE (V)
SUPPLY CURRENT (mA)
VSENSE = 100mV
MAX4073H
MAX4073F
MAX4073T
0
0.2
0.1
0.4
0.3
0.6
0.5
0.7
-50 0 25-25 50 75 100 125
SUPPLY CURRENT vs.
TEMPERATURE
MAX4073 toc03
TEMPERATURE (˚C)
SUPPLY CURRENT (mA)
VSENSE = 0
VCC = +28V
0.47
0.49
0.48
0.51
0.50
0.53
0.52
0.54
010155 202530
SUPPLY CURRENT vs.
VRS+ VOLTAGE
MAX4073 toc04
VRS+ (V)
SUPPLY CURRENT (mA)
VSENSE = 6.25mV
MAX4073H
MAX4073F
MAX4073T
-1.0
-0.4
-0.6
-0.8
-0.2
0
0.2
0.4
0.6
0.8
1.0
0105 15202530
TOTAL OUTPUT ERROR vs.
SUPPLY VOLTAGE
MAX 4073 toc07
SUPPLY VOLTAGE (V)
TOTAL OUTPUT ERROR (%)
VSENSE = 100mV MAX4073F
MAX4073H
MAX4073T
0.60
0.90
0.80
0.70
1.00
1.10
1.20
1.30
1.40
1.50
1.60
0105 15202530
SUPPLY CURRENT vs.
VRS+ VOLTAGE
MAX4073 toc05
VRS+ (V)
SUPPLY CURRENT (mA)
VSENSE = 100mV
MAX4073H
MAX4073F
MAX4073T
0
0.3
0.2
0.1
0.5
0.4
0.9
0.8
0.7
0.6
1.0
-50 -25 0 25 50 75 100 125
OUTPUT HIGH VOLTAGE
(VCC - VOH) vs. TEMPERATURE
MAX4073 toc06
TEMPERATURE (°C)
VCC - VOH (V)
VSENSE = 150mV
-2.0
-1.5
-1.0
-0.5
0
0.5
1.0
1.5
2.0
0105 15202530
TOTAL OUTPUT ERROR
vs. SUPPLY VOLTAGE
MAX4073 toc08
SUPPLY VOLTAGE (V)
TOTAL OUTPUT ERROR (%)
VSENSE = 6.25mV
Typical Operating Characteristics
(VCC = +12V, VRS+ = +12V, VSENSE = 100mV, CL= 5pF, TA= +25°C, unless otherwise noted.)
-3.0
-2.5
-2.0
-1.5
-1.0
-0.5
0
0.5
1.0
0105 15202530
TOTAL OUTPUT ERROR
vs. COMMON-MODE VOLTAGE
MAX4073 toc09
COMMON-MODE VOLTAGE (V)
TOTAL OUTPUT ERROR (%)
MAX4073T/F/H
Low-Cost, SC70, Voltage-Output,
High-Side Current-Sense Amplifier
5
Maxim Integrated
-1.0
-0.6
-0.8
-0.2
-0.4
0.2
0
0.4
0.8
0.6
1.0
-50 0 25-25 50 75 100 125 150
TOTAL OUTPUT ERROR
vs. TEMPERATURE
MAX4073 toc10
TEMPERATURE (°C)
TOTAL OUTPUT ERROR (%)
VCC = +12V
VCC = +28V
GAIN ACCURACY
vs. TEMPERATURE
MAX4073 toc11
-2.0
-1.5
-0.5
-1.0
1.0
1.5
0.5
0
2.0
GAIN ACCURACY (%)
-50 0 25-25 50 75 100 125
TEMPERATURE (°C)
VSENSE = (10mV - 100mV)
100 1000
5
10
15
20
25
35
30
40
45
0.1 1 10
SMALL-SIGNAL GAIN vs.
FREQUENCY
MAX4073 toc12
FREQUENCY (kHz)
GAIN (dB)
0
10,000
MAX4073H
MAX4073F
MAX4073T
Typical Operating Characteristics (continued)
(VCC = +12V, VRS+ = +12V, VSENSE = 100mV, CL= 5pF, TA= +25°C, unless otherwise noted.)
100
20
0.1 10 100
POWER-SUPPLY REJECTION
RATIO vs. FREQUENCY
40
30
50
60
70
80
90
MAX4073 toc13
FREQUENCY (kHz)
PSRR (dB)
11000
MAX4073H
MAX4073F
MAX4073T
1µs/div
MAX4073T SMALL-SIGNAL
TRANSIENT RESPONSE
VSENSE
2.5mV/div
OUT
50mV/div
95mV
100mV
2V
1.9V
MAX4073 toc14
1µs/div
MAX4073F SMALL-SIGNAL
TRANSIENT RESPONSE
VSENSE
2.5mV/div
OUT
125mV/div
95mV
100mV
5V
4.75V
MAX4073 toc15
1µs/div
MAX4073H SMALL-SIGNAL
TRANSIENT RESPONSE
VSENSE
2.5mV/div
95mV
100mV
10V
9.5V
MAX4073 toc16
OUT
250mV/div
MAX4073T/F/H
Low-Cost, SC70, Voltage-Output,
High-Side Current-Sense Amplifier
6Maxim Integrated
Typical Operating Characteristics (continued)
(VCC = +12V, VRS+ = +12V, VSENSE = 100mV, CL= 5pF, TA= +25°C, unless otherwise noted.)
1µs/div
MAX4073T LARGE-SIGNAL
TRANSIENT RESPONSE
VSENSE
45mV/div
OUT
0.9V/div
6.25mV
100mV
2V
0.120V
MAX4073 toc17
1µs/div
MAX4073F LARGE-SIGNAL
TRANSIENT RESPONSE
VSENSE
45mV/div
OUT
2.35V/div
6.25mV
100mV
5V
0.3V
MAX4073 toc18
1µs/div
MAX4073H LARGE-SIGNAL
TRANSIENT RESPONSE
VSENSE
45mV/div
OUT
4.7V/div
6.25mV
100mV
10V
0.6V
MAX4073 toc19
Detailed Description
The MAX4073 high-side current-sense amplifier fea-
tures a +2V to +28V input common-mode range that is
independent of supply voltage. This feature allows the
monitoring of current out of a battery as low as +2V and
also enables high-side current sensing at voltages
greater than the supply voltage (VCC).
The MAX4073 operates as follows: current from the
source flows through RSENSE to the load (Figure 1). Since
the internal-sense amplifier’s inverting input has high
impedance, negligible current flows through RG2
(neglecting the input bias current). Therefore, the
sense amplifier’s inverting-input voltage equals
VSOURCE - (ILOAD)(RSENSE). The amplifier’s open-loop
gain forces its noninverting input to the same voltage as
the inverting input. Therefore, the drop across RG1
equals (ILOAD)(RSENSE). Since IRG1 flows through RG1,
IRG1 = (ILOAD)(RSENSE) / RG1. The internal current mirror
multiplies IRG1 by a current gain factor, β, to give
IRGD = β✕IRG1. Solving IRGD = β✕(ILOAD)(RSENSE)/
RG1. Assuming infinite output impedance, VOUT = (IRGD)
(RGD). Substituting in for IRGD and rearranging, VOUT =
β✕(RGD/RG1)(RSENSE ✕ILOAD). The parts gain equals
β✕RGD/RG1. Therefore, VOUT = (GAIN) (RSENSE)
(ILOAD), where GAIN = 20V/V for MAX4073T, GAIN =
50V/V for MAX4073F, and GAIN = 100V/V for MAX4073H.
Set the full-scale output range by selecting RSENSE and
the appropriate gain version of the MAX4073.
Applications Information
Recommended Component Values
The MAX4073 senses a wide variety of currents with
different sense resistor values. Table 1 lists common
resistor values for typical operation of the MAX4073.
Choosing RSENSE
To measure lower currents more accurately, use a
large value for RSENSE. The larger value develops a
higher-sense voltage that reduces offset voltage errors
of the internal op amp. Typical sense voltages range
between 10mV and 150mV.
In applications monitoring very high currents, RSENSE
must be able to dissipate the 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 maxi-
mum ratings (±5V).
If ISENSE has a large high-frequency component, mini-
mize the inductance of RSENSE. Wire-wound resistors
have the highest inductance, metal-film resistors are
MAX4073T/F/H
Low-Cost, SC70, Voltage-Output,
High-Side Current-Sense Amplifier
7
Maxim Integrated
Pin Description
PIN
SOT23 SC70
NAME FUNCTION
1, 2 2 GND Ground
33V
CC Supply Voltage Input. Bypass to GND with a 0.1µF capacitor.
4 4 RS+ Power-Side Connection to the External Sense Resistor
5 5 RS- Load-Side Connection to the External Sense Resistor
6 1 OUT Voltage Output. VOUT is proportional to VSENSE. Output impedance is approximately
12kΩ.
RSENSE
VSOURCE
+2V TO +28V
+3V TO +28V
RGD = 12kΩ
VOUT
IRG1
IRGD
ILOAD
RG1 RG2
RS-RS+
OUT
GND
TO LOAD/BATTERY
VCC
CURRENT
MIRROR
A1
MAX4073T/F/H
Figure 1. Functional Diagram
MAX4073T/F/H
Low-Cost, SC70, Voltage-Output,
High-Side Current-Sense Amplifier
8Maxim Integrated
somewhat better, and low-inductance metal-film resis-
tors are best suited for these applications.
For VSENSE = 100mV, full-scale output voltage can be
2V, 5V, or 10V depending on the gain. For proper oper-
ation, ensure VCC exceeds the full-scale output voltage
by 1.2V (see Output High Voltage (VCC - VOH) vs.
Temperature in the
Typical Operating Characteristics
).
Using a PCB 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 0.1-inch-wide trace of
2-ounce copper is approximately 30mΩ/ft. The resis-
tance-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, do not exceed the maximum power
dissipation of the copper trace.
For example, the MAX4073T (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 2 inches of 0.1 inch-
wide copper trace.
Output Impedance
The output of the MAX4073 is a current source driving a
12kΩresistance. Resistive loading added to OUT
reduces the output gain of the MAX4073. To minimize
output errors for most applications, connect OUT to a
high-impedance input stage. When output buffering is
required, choose an op amp with a common-mode
input range and an output voltage swing that includes
ground when operating with a single supply. The op
amp’s supply voltage range should be at least as high
as any voltage the system may encounter.
The percent error introduced by output loading is deter-
mined with the following formula:
where RLOAD is the external load applied to OUT.
Current Source Circuit
Figure 3 shows a block diagram using the MAX4073
with a switching regulator to make a current source.
% 100 R
12k R 1
ERROR LOAD
LOAD
=Ω+−
⎛
⎝
⎜
⎞
⎠
⎟
MAX4073T
VSENSE
RSENSE
+3V TO +28V
0.1µF
RS+
+
0.3in COPPER
INPUT LOAD/BATTERY
0.3in COPPER0.1in COPPER
RS-
GND
OUT
VCC
_
Figure 2. MAX4073T Connections Showing Use of PC Board
Figure 3. Current Source
MAX4073T/F/H
RSENSE
ILOAD
+2V TO +28V VSENSE
VCC
OUT
VIN
GND
RS+
+3V TO +28V
0.1µF
RS-
LOAD/
BATTERY
LOW-COST
SWITCHING
REGULATOR
MAX4073T/F/H
Low-Cost, SC70, Voltage-Output,
High-Side Current-Sense Amplifier
9
Maxim Integrated
Table 1. Recommended Component Values
10.0100
5.050
2.0
10 10
20
10.0100
5.050
2.0
520
20
10.0100
5.050
2.0
1100
20
10.0100
5.0501000
CURRENT-SENSE RESISTOR
RSENSE (mΩ)
20
GAIN
2.0
0.1
FULL-SCALE OUTPUT VOLTAGE
(FULL-SCALE VSENSE = 100mV)
VOUT (V)
FULL-SCALE LOAD CURRENT
ILOAD (A)
5RS-
GND
GND
RS+VCC
16OUT
MAX4073T/F/H
2
34
SOT23
GND
VCC
15
RS-
OUT
MAX4073T/F/H
SC70
++
2
34
TOP VIEW
RS+
Pin Configurations
Chip Information
PROCESS: Bipolar
MAX4073T/F/H
Low-Cost, SC70, Voltage-Output,
High-Side Current-Sense Amplifier
10 Maxim Integrated
SC70, 5L.EPS
PACKAGE OUTLINE, 5L SC70
21-0076 1
1
E
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 SC70 X5+1 21-0076 90-0188
6 SOT23 U6+4 21-0058 90-0175
MAX4073T/F/H
Low-Cost, SC70, Voltage-Output,
High-Side Current-Sense Amplifier
11
Maxim Integrated
6LSOT.EPS
PACKAGE OUTLINE, SOT 6L BODY
21-0058
2
1
I
PACKAGE OUTLINE, SOT 6L BODY
21-0058
2
2
I
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.
MAX4073T/F/H
Low-Cost, SC70, Voltage-Output,
High-Side Current-Sense Amplifier
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim 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.
12
_______________________________Maxim Integrated 160 Rio Robles, San Jose, CA 95134 USA 1-408-601-1000
© 2012 Maxim Integrated Products The Maxim logo and Maxim Integrated are trademarks of Maxim Integrated Products, Inc.
Revision History
REVISION
NUMBER
REVISION
DATE DESCRIPTION PAGES
CHANGED
0 5/01 Initial release —
2 8/12 Added lead-free notation to Ordering Information. 1