Datasheet MAX4372TESA, MAX4372HEUK-T, MAX4372HESA, MAX4372FEUK-T, MAX4372FESA Datasheet (Maxim)

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General Description

The MAX4372 low-cost, precision, high-side current­sense amplifier is available in a tiny, space-saving
SOT23-5 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 com­mon-mode 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 2­cell 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
♦ Low 1.5Ω Output Impedance
♦ Three Gain Versions Available

+20V/V (MAX4372T)
+50V/V (MAX4372F)
+100V/V (MAX4372H)

♦ Wide 0 to +28V Common-Mode Range,

Independent of Supply Voltage

♦ Available in Space-Saving SOT23-5 Package

MAX4372T/F/H

Low-Cost, SOT23, Micropower, High-Side

Current-Sense Amplifier with Voltage Output

________________________________________________________________

Maxim Integrated Products

1

19-1548; Rev 0; 10/99

PART

MAX4372TEUK-T

MAX4372TESA

MAX4372FEUK-T -40°C to +85°C

-40°C to +85°C

-40°C to +85°C

TEMP. RANGE PIN-PACKAGE

5 SOT23-5

8 SO

5 SOT23-5

Pin Configurations

Ordering Information

TOP

MARK

ADIU

—

ADIV

MAX4372FESA

MAX4372HEUK-T

MAX4372HESA -40°C to +85°C

-40°C to +85°C

-40°C to +85°C 8 SO

5 SOT23-5

8 SO

—

ADIW

—

RS-

OUT

A/D

CONVERTER

V

CC

V

CC

GND

RS+

R

SENSEVSENSE

I

LOAD

V

IN

0 TO 28V

+2.7V TO +28V

0.1µF

MAX4372T/F/H

LOAD/

BATTERY

Typical Operating Circuit

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.

TOP VIEW

GND

15RS-

MAX4372T/F/H

OUT

2

V

CC

34

SOT23-5

RS+

GND

V

CC

1

2

MAX4372T/F/H

3

4

SO

87RS+

N.C.N.C.

RS-

6

N.C.OUT

5

MAX4372T/F/H

Low-Cost, SOT23, Micropower, High-Side
Current-Sense Amplifier with Voltage Output

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(V

RS+

= 0 to +28V, VCC= +2.7V to +28V, V

SENSE

= 0, R

LOAD

= 1MΩ, T

A

= T

MIN

to T

MAX

, unless otherwise noted. Typical values are

at T

A

= +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, RS+, RS- to GND ...........................................-0.3V to +30V

OUT to GND ...........................................................-0.3V to +15V

Differential Input Voltage (V

RS+

- V

RS-

) ..............................±0.3V

Current into Any Pin..........................................................±10mA

Continuous Power Dissipation (T

A

= +70°C)

5-Pin SOT23 (derate 7.1mW/°C above +70°C).............571mW

8-Pin SO (derate 5.88mW/°C above +70°C).................471mW

Operating Temperature Range ...........................-40°C to +85°C

Storage Temperature Range .............................-65°C to +150°C

Lead Temperature (soldering, 10sec). ............................+300°C

VCC= 2.7V, I

OUT

= -500µA

VCC= 2.7V

V

RS+

≤ 2V

V

RS+

> 2V

V

RS+

≤ 2V

V

RS+

> 2V

V

RS+

> 2V

V

RS+

> 2V, V

SENSE

= 5mV

Gain = +100V/V

VCC= 0

Gain = +20V/V or +50V/V

CONDITIONS

V0.1 0.25VCC- V

OH

OUT High Voltage

965

OUT Low Voltage mV

2.6

mV

100

V

SENSE

150

Full-Scale Sense Voltage
(Note 4)

V028V

CMR

Common-Mode Input Range
(Note 3)

V2.7 28V

CC

Operating Voltage Range
(Note 2)

µA

-50 2

I

RS-

Input Bias Current

02

-25 2

I

RS+

01

dB85CMRCommon-Mode Rejection

µA30 60I

CC

Supply Current

µA0.05 1.2I

RS+

, I

RS-

Leakage Current

UNITSMIN TYP MAXSYMBOLPARAMETER

I

OUT

= 10µA

I

OUT

= 100µA

V

SENSE

= 100mV, VCC= 12V,

V

RS+

= 12V, TA= +25°C (Note 6)

%±0.18 ±3

Full-Scale Accuracy
(Note 5)

V

SENSE

= 100mV, VCC= 12V,

V

RS+

= 12V (Note 6)

±6

V

SENSE

= 100mV, VCC= 28V,

V

RS+

= 28V (Note 6)

±0.15 ±7

V

SENSE

= 100mV, VCC= 12V,

V

RS+

= 0.1V (Note 6)

±1 ±28

V

SENSE

= 6.25mV, VCC= 12V,

V

RS+

= 12V (Note 7)

%

±0.15

Total OUT Voltage Error
(Note 5)

MAX4372T/F/H

Low-Cost, SOT23, Micropower, High-Side

Current-Sense Amplifier with Voltage Output

_______________________________________________________________________________________ 3

ELECTRICAL CHARACTERISTICS (continued)

(V

RS+

= 0 to +28V, VCC= +2.7V to +28V, V

SENSE

= 0, R

LOAD

= 1MΩ, T

A

= T

MIN

to T

MAX

, unless otherwise noted. Typical values are

at T

A

= +25°C.) (Note 1)

Note 1: All devices are 100% production tested at T

A

= +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: Total OUT voltage error is the sum of gain and offset voltage errors.
Note 6: Measured at I

OUT

= -500µA (R

LOAD

= 4kΩ for gain = +20V/V, R

LOAD

= 10kΩ for gain = +50V/V, R

LOAD

= 20kΩ for gain =

+100V/V).

Note 7: +6.25mV = 1/16 of +100mV full-scale voltage (C/16).
Note 8: The device will not reverse phase when overdriven.

V

RS

+

= 12V,

V

CC

= 12V,

C

LOAD

= 10pF

CONDITIONS

MAX4372T 20

V

SENS

E

= 100mV,

gain = +20V/V

kHz

50

BW

275

UNITSMIN TYP MAXSYMBOLPARAMETER

V

SENSE

= 100mV,

gain = +50V/V

200

V

SENSE

= 100mV,

gain = +100V/V

110

-3dB Bandwidth

MAX4372F

MAX4372H

V/V

100

Gain 50

No sustained oscillations

V

SENSE

= 100mV Ω1.5R

OUT

OUT Output Resistance

pF1000Capacitive Load Stability

V

SENSE

= 20mV

to 100mV

%

±5.5

Gain Accuracy

V

OUT

= 2V, V

RS+

> 2V

VCC= 12V, V

RS+

= 12V, C

LOAD

= 10pF ms0.1

Saturation Recovery Time
(Note 8)

VCC= 12V, V

RS+

= 12V,

V

SENSE

= 100mV, C

LOAD

= 10pF

ms0.5

Power-Up Time to 1% of
Final Value

dB75 85PSRPower-Supply Rejection

V

SENSE

= 6.25mV

±0.25 ±2.5TA= +25°C

TA= -40°C to +85°C

V

SENSE

= 6.25mV to

100mV

20

V

SENSE

= 100mV to

6.25mV

Gain = +20V/V,
VCC= 12V,
V

RS+

= 12V,

C

LOAD

= 10pF

µs

20

OUT Settling Time to 1% of
Final Value

MAX4372T/F/H

Low-Cost, SOT23, Micropower, High-Side
Current-Sense Amplifier with Voltage Output

4 _______________________________________________________________________________________

Typical Operating Characteristics

(VCC= +12V, V

RS+

= 12V, V

SENSE

= 100mV, TA = +25°C, unless otherwise noted.)

25.0

27.5

30.0

32.5

35.0

SUPPLY CURRENT vs. SUPPLY VOLTAGE

MAX4372 toc01

SUPPLY VOLTAGE (V)

SUPPLY CURRENT (µA)

012164 8 20 24 28

AV = +100V/V

AV = +50V/V

AV = +20V/V

V

SENSE

= 5mV

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)

V

SENSE

= 5mV

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)

012164 8 20 24 28

AV = +100V/V

AV = +50V/V

AV = +20V/V

V

SENSE

= 5mV

-1.2

-0.8

-1.0

-0.2

-0.4

-0.6

0.4

0.2

0

0.6

0105 15202530

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

0105 15202530

TOTAL OUTPUT ERROR

vs. COMMON-MODE VOLTAGE

MAX4372T toc07

COMMON-MODE VOLTAGE (V)

OUTPUT ERROR (%)

G = +100V/V

G = +50V/V

G = +20V/V

-1.0

-0.5

0.5

0

1.0

1.5

0 10050 150 200 250 300

TOTAL OUTPUT ERROR vs. V

SENSE

MAX4372T toc05

V

SENSE

(mV)

OUTPUT ERROR (%)

AV = +100V/V

AV = +20V/V

AV = +50V/V

-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

-0.9

-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

-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

V

OUT

V

SENSE

600mV

200mV

30mV

10mV

MAX4372T

SMALL-SIGNAL TRANSIENT RESPONSE

MAX4372T toc10

20µs/div

V

OUT

V

SENSE

1.5V

0.5V

30mV

10mV

MAX4372F

SMALL-SIGNAL TRANSIENT RESPONSE

MAX4372T toc11

20µs/div

V

OUT

V

SENSE

3V

1V

30mV

10mV

MAX4372H

SMALL-SIGNAL TRANSIENT RESPONSE

MAX4372T toc12

20µs/div

V

OUT

V

SENSE

1V

3V

50mV

150mV

MAX4372T

LARGE-SIGNAL TRANSIENT RESPONSE

MAX4372T toc13

20µs/div

V

OUT

V

SENSE

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

V

OUT

V

SENSE

0

10V

0

100mV

MAX4372H

LARGE-SIGNAL TRANSIENT RESPONSE

20µs/div

MAX4372T toc15

MAX4372T/F/H

Low-Cost, SOT23, Micropower, High-Side

Current-Sense Amplifier with Voltage Output

_______________________________________________________________________________________

5

Typical Operating Characteristics (continued)

(VCC= +12V, V

RS+

= 12V, V

SENSE

= 100mV, TA = +25°C, unless otherwise noted.)

_______________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). Since A1’s inverting input is
high impedance, the voltage on the negative terminal
equals VIN- V

SENSE

. A1 forces its positive terminal to
match its negative terminal; therefore, the voltage
across RG1(VIN- V1-) equals V

SENSE

. This creates a

current to flow through RG1equal to V

SENSE

/ 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:

I

M

= β V

SENSE

/ R

G1

A2’s positive terminal presents high impedance, so this
current flows through RGD, with the following result:

V2+= R

GD

β · V

SENSE

/ R

G1

R1 and R2 set the closed-loop gain for A2, which
amplifies V2+, yielding:

V

OUT

= R

GD

· β · V

SENSE

/ RG1(1 + R2 / R1)

The gain of the device equals:

V

OUT

= R

GD

· β (1 + R2 / R1) / R

G1

V

SENSE

__________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.

Choosing R

SENSE

Given the gain and maximum load current, select
R

SENSE

such that VCC- V

OUT

does not exceed +0.25V

and V

OUT

does not exceed +10V. To measure lower

currents more accurately, use a high value for R

SENSE

.
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
R

SENSE

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.

MAX4372T/F/H

Low-Cost, SOT23, Micropower, High-Side
Current-Sense Amplifier with Voltage Output

6 _______________________________________________________________________________________

Pin Description

1 3 Ground

2 4 Output Voltage. V

OUT

is proportional to the magnitude of V

SENSE(VRS+

- V

RS-

).

PIN

GND

OUT

SO

FUNCTION

SOT23-5

NAME

3 1 Supply Voltage

4 8 Power Connection to the External Sense Resistor

V

CC

RS+

5 6 Load-Side Connection to the External Sense Resistor

— 2, 5, 7 No Connection. Not internally connected.

RS-

N.C.

Figure 1. Functional Diagram

+2.7V

V

CC

TO

+28V

CURRENT

MIRROR

MAX4372T/F/H

OUT

RS+

RS-

GND

R

SENSE

0 TO +28V

I

LOAD

LOAD

V

IN

V

SENSE

TO

R

G1

V1+

A1

V1-

R

G2

R

I

M

A2

R2

GD

V2+

V2-

R1

MAX4372T/F/H

Low-Cost, SOT23, Micropower, High-Side

Current-Sense Amplifier with Voltage Output

_______________________________________________________________________________________ 7

Using a PC Board Trace as R

SENSE

If the cost of R

SENSE

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 about 30mΩ/ft. The resistance tem-

perature 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 will introduce 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 R

SENSE

of 5mΩ) creates a full-scale

V

SENSE

of 50mV that yields a maximum V

OUT

of 1V.

R

SENSE

, in this case, requires about 2 inches of 0.1-

inch-wide copper trace.

Table 1. Recommended Component Values

FULL-SCALE LOAD

CURRENT,

I

LOAD

(A)

GAIN

(V/V)

CURRENT-SENSE

RESISTOR,

R

SENSE

(mΩ)

2.0

FULL-SCALE OUTPUT

VOLTAGE (FULL-SCALE

V

SENSE

= 100mV),

V

OUT

(V)

5.0

10.0

0.1 1000

20

100

50

2.0

100

50 5.0

10.0

1 100

20

2.0

100

50 5.0

2.0

100

50 5.0

10.0

5 20

20

10.0

10 10

20

Figure 2. Connections Showing Use of PC Board

Chip Information

TRANSISTOR COUNT: 225

INPUT LOAD/BATTERY

0.1in COPPER 0.3in COPPER0.3in COPPER

RS+

MAX4372T/F/H

RS-

R

V

SENSE

SENSE

V

OUT

GND

CC

+2.7V TO +28V

MAX4372T/F/H

Low-Cost, SOT23, Micropower, High-Side
Current-Sense Amplifier with Voltage Output

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.

8

_____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600

© 1999 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.

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.

8

_____________________Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600

© 1999 Maxim Integrated Products Printed USA is a registered trademark of Maxim Integrated Products.

Package Information

SOT5L.EPS