MAX4373/74/75 Datasheet by Maxim Integrated

Genera‘-System/Board-Leve\ Current Monrtorrng Precrsron Current Sources ’C to +85” r I MAXAiS/S : 41% i 7 ; maxi m integrated

MAX4373/MAX4374/MAX4375 Low-Cost, Micropower, High-Side

Current-Sense Amplifier +

Comparator + Reference ICs

EVALUATION KIT AVAILABLE

General Description

The MAX4373/MAX4374/MAX4375 low-cost, micropow-

er, high-side current-sense supervisors contain a high-

side current-sense amplifier, bandgap reference, and

comparator with latching output. They feature a voltage

output that eliminates the need for gain-setting resistors,

making them 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 0 to +28V input common-mode range is

independent of the supply voltage, which ensures that

the current-sense feedback remains viable even when

connected to a battery pack in deep discharge.

The comparator output of the MAX4373/MAX4374/

MAX4375 is latched to provide a turn-off flag that

doesn’t oscillate. In addition, the MAX4374/MAX4375

contain a second comparator for use in window-detec-

tion functions. The MAX4373/MAX4374/MAX4375 are

available in three different gain versions (T = +20V/V,

F = +50V/V, H = +100V/V) and use an external sense

resistor to set the sensitivity of the input voltage to the

load current. These features offer a high level of inte-

gration, resulting in a simple and compact current-

sense solution.

The MAX4373/MAX4374/MAX4375 operate from a sin-

gle +2.7V to +28V supply and consume 50µA. They are

specified for the extended operating temperature range

(-40°C to +85°C) and are available in 8-pin and 10-pin

µMAX® packages.

Applications

Notebook Computers

Portable/Battery-Powered Systems

Smart Battery Packs/Chargers

Cell Phones

Power-Management Systems

General-System/Board-Level Current Monitoring

Precision Current Sources

Benefits and Features

•Integrated Current-Sensing Solution Simplifies High-

Side Current Monitoring

•Current-Sense Amplifier plus Internal Comparator

and Bandgap Reference with Improved Accuracy

•1mV (max) Input Offset Voltage

•2% (max) Full-Scale Accuracy

•Internal Bandgap Reference (±1.6% Accuracy)

•High Accuracy +2V to +28V Common-Mode Range,

Functional Down to 0V, Independent of Supply

Voltage Ensures Current Monitoring Even In Deep

Discharge of Battery Pack

•Low Power Consumption Extends Battery Life

•50µA Supply Current

•Single +2.7V to +28V Operating Supply

•Latching Comparator Output Eliminates Oscillation

•Three Gain Versions (+20V/V, +50V/V,

+100V/V) Support Different Size Battery Packs

MAX4373

RS-RS+

OUT

CIN

LOAD/

BATTERY

VCC = 2.7V TO 28V

VIN = 0 TO 28V

GND

VCC

RSENSE

+ VSENSE -ILOAD

VPULL-UP

(UP TO 5V)

COUT

0.1µF

RESET

Pin Configurations appear at end of data sheet.

Denotes a lead(Pb)-free/RoHS-compliant package.

Ordering Information continued at end of data sheet.

Ordering Information

PART TEMP RANGE PIN-

PACKAGE

GAIN

(V/V)

MAX4373TEUA+ -40°C to +85°C 8 µMAX +20

MAX4373TESA+ -40°C to +85°C 8 SO +20

MAX4373FEUA+ -40°C to +85°C 8 µMAX +50

MAX4373FESA+ -40°C to +85°C 8 SO +50

MAX4373HEUA+ -40°C to +85°C 8 µMAX +100

MAX4373HESA+ -40°C to +85°C 8 SO +100

µMAX is a registered trademark of Maxim Integrated Products, Inc.

Typical Operating Circuit

19-1630; Rev 5; 5/15

MAX4373/MAX4374/MAX4375 Low-Cost, Micropower, High-Side

Current-Sense Amplifier +

Comparator + Reference ICs

Maxim Integrated | 2www.maximintegrated.com

Absolute Maximum Ratings

Electrical Characteristics

(VCC = +2.7V to +28V, VRS+ = 0 to +28V, VSENSE = 0V, VRESET = 0V, RLOAD= 1MΩ, 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, RS+, RS- to GND ...........................................-0.3V to +30V

OUT to GND ................................................-0.3V to the lesser of

(VCC + 0.3V) or +15V

CIN1, CIN2, RESET to GND ........................-0.3V to the lesser of

(VCC + 0.3V) or +12V

Differential Input Voltage (VRS+ - VRS-)..............................±0.3V

COUT1, COUT2 to GND........................................-0.3V to +6.0V

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

Continuous Power Dissipation (TA= +70°C)

8-Pin µMAX (derate 4.1mW/°C above +70°C) .............330mW

8-Pin SO (derate 5.9mW/°C above +70°C)..................471mW

10-Pin µMAX (derate 5.6mW/°C above +70°C) ...........444mW

14-Pin SO (derate 8.3mW/°C above +70°C)................667mW

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

Junction Temperature......................................................+150°C

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

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

Soldering Temperature (reflow) .......................................+260°C

PARAMETER SYMBOL MIN TYP MAX UNITS

-25 2.0

Input Bias Current

IRS+

0 2.5

µA

Leakage Current IRS+, IRS- ±0.015 ±0.5 µA

Supply Current ICC 50 100 µA

IRS-

-50 4

Full-Scale Sense Voltage

(Note 4) VSENSE

150 170 mV

100 120

Common-Mode Input Range

(Note 3)

Operating Voltage Range

(Note 2) VCC 2.7 28 V

VCMR 028V

Common-Mode Rejection CMR 85 dB

OUT Voltage High VCC -

VOH 0.25 V

CONDITIONS

VRS+ ≤2V

VRS+ > 2V

VCC = 0V, VRS+ = 28V

VRS+ > 2V, VSENSE = 5mV

VRS+ > 2V

VRS+ ≤2V

VCC = 2.7V, IOUT = -500µA, VRS+ = 12V

Gain = +20V/V, +50V/V, VRS+ = 12V

Gain = +100V/V, VRS+ = 12V

VRS+ > 2V

Input Offset Voltage VOS

0.1 1

VCC = VRS+ = 12V

(Note 11)

TA= +25°C

TA= TMIN to TMAX 2

8.5 65IOUT = 100µA

IOUT = 10µA

OUT Voltage Low VOUT

2.5 mV

VCC = 2.7V,

VRS+ = 12V

±0.30 ±2TA= +25°C

VSENSE =

100mV

(Note 6)

±3

VCC = 12V,

VRS+ = 12V TA= TMIN to TMAX

±0.35 ±2

VCC = 28V,

VRS+ = 28V

TA= +25°C

±3TA= TMIN to TMAX

±5.0VCC = 12V, VRS+ = 0.1V

VSENSE = 6.25mV, VCC = 12V,

VRS+ = 12V (Note 7)

Total OUT Voltage Error

(Note 5) VOUT

±5.0

MAX4373/MAX4374/MAX4375 Low-Cost, Micropower, High-Side

Current-Sense Amplifier +

Comparator + Reference ICs

Maxim Integrated | 3www.maximintegrated.com

Electrical Characteristics (continued)

(VCC = +2.7V to +28V, VRS+ = 0 to +28V, VSENSE = 0V, VRESET = 0V, RLOAD= 1MΩ, TA= TMIN to TMAX, unless otherwise noted.

Typical values are at TA= +25°C.) (Note 1)

±0.3 ±1.7

±2.7TA= -40°C to +85°C

TA= +25°C

VSENSE =

20mV to 100mV,

VCC = 12V, VRS+ =

12V, Gain = 100

Output Low Voltage VOL 0.6 VISINK = 1mA

Propagation Delay 4µs

CL= 10pF, RL= 10kΩpull-up to 5V,

5mV of overdrive

Input Bias Current IB±2.2 ±15 nA

Comparator Hysteresis -9 mV

0.1 ms

Saturation Recovery Time

(Note 8) VCC = 12V, VRS+ = 12V, CLOAD = 10pF

Power-Supply Rejection

Power-Up Time to 1% of Final

Value

PSR

VSENSE = 100mV to

6.25mV

VSENSE = 6.25mV to

100mV

±2.7TA= -40°C to +85°C

TA= +25°C

+50

+100

MAX437_F

MAX437_H

VSENSE = 6.25mV

VSENSE = 100mV,

Gain = +100V/V

VSENSE = 100mV,

Gain = +50V/V

VSENSE = 100mV,

Gain = +20V/V

110

120

PARAMETER SYMBOL MIN TYP MAX UNITS

72 87

OUT Output Resistance ROUT 1.5 Ω

Capacitive Load Stability 1000 pF

OUT Settling Time to 1% of

Final Value

µs

0.5

Comparator Threshold VTH

590 600 610 mV

Gain

-3dB Bandwidth BW

200

kHz

+20

V/V

Gain Accuracy ΔAV

±0.3 ±1.7

CONDITIONS

VOUT = 2V, VRS+ > 2V

VSENSE = 100mV

No sustained oscillations

Gain = +20V/V,

VCC = 12V,

VRS+ = 12V,

CLOAD = 10pF

VSENSE = 100mV, CLOAD = 10pF,

VCC = 12V, VRS+ = 12V

TA= +25°C

VRS+ = 12V,

VCC = 12V,

CLOAD = 10pF

MAX437_T

VSENSE =

20mV to 150mV;

VCC = 12V; VRS+ =

12V; Gain = 20, 50

586 614TA= TMIN to TMAX

COMPARATOR (Note 9)

SEE Elam A, SEE :92 60 5a

MAX4373/MAX4374/MAX4375 Low-Cost, Micropower, High-Side

Current-Sense Amplifier +

Comparator + Reference ICs

Maxim Integrated | 4www.maximintegrated.com

010155 202530

SUPPLY CURRENT

vs. SUPPLY VOLTAGE

MAX4373 toc01

SUPPLY VOLTAGE (V)

SUPPLY CURRENT (μA)

MAX4373

MAX4374/MAX4375

VSENSE = 5mV

0105 15202530

SUPPLY CURRENT

vs. COMMON-MODE VOLTAGE

MAX4373 toc02

COMMON-MODE VOLTAGE (V)

SUPPLY CURRENT (μA)

MAX4374/MAX4375

MAX4373

VSENSE = 5mV

-2.0

-0.5

-1.0

-1.5

0.5

1.5

1.0

2.0

2684 10121416182022242628

TOTAL OUTPUT ERROR

vs. SUPPLY VOLTAGE

MAX4373 toc03

SUPPLY VOLTAGE (V)

OUTPUT ERROR (%)

AV = +100V/V

AV = +20V/V

AV = +50V/V

VSENSE = 100mV

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: Guaranteed by Gain Accuracy test. Output voltage is internally clamped not to exceed 12V.

Note 5: Total OUT Voltage Error and Full-Scale Accuracy are the sum of gain and offset voltage errors.

Note 6: Measured at IOUT = -500µA (RLOAD = 4kΩfor gain of +20V/V, RLOAD = 10kΩfor gain of +50V/V, RLOAD = 20kΩfor gain of

+100V/V).

Note 7: +6.25mV = 1/16 of +100mV full-scale voltage.

Note 8: The device will not experience phase reversal when overdriven.

Note 9: All comparator tests are done with VRS+ = +12V.

Note 10: VPULL-UP is defined as an externally applied voltage through a resistor to pull up the comparator output.

Note 11: VOS is extrapolated from the gain accuracy test.

Electrical Characteristics (continued)

(VCC = +2.7V to +28V, VRS+ = 0 to +28V, VSENSE = 0V, VRESET = 0V, RLOAD= 1MΩ, TA= TMIN to TMAX, unless otherwise noted.

Typical values are at TA= +25°C.) (Note 1)

VCC = 28V, VPULL-UP = 5V (Note 10)

CONDITIONS

µA1

Output High Leakage Current

UNITSMIN TYP MAX

SYMBOLPARAMETER

V2.0

VIH

RESET Input High Voltage

V0.8

VIL

RESET Input Low Voltage

VIL = 0, VIH = 5.5V, VCC = 28V µA-0.5 0.5

IIL, IIH

Logic Input Current

µs3

tRPD

RESET Propagation Delay

µs1.5

tRPW

Minimum RESET Pulse Width

Typical Operating Characteristics

(VRS+ = +12V, VCC = +12V, RLOAD = 1MΩ, VRESET = 0V, VSENSE = 100mV, VPULL-UP = +5V, RPULL-UP = 10kΩ, TA= +25°C, unless

otherwise noted.)

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MAX4373/MAX4374/MAX4375 Low-Cost, Micropower, High-Side

Current-Sense Amplifier +

Comparator + Reference ICs

Maxim Integrated | 5www.maximintegrated.com

-1

-2

-3

-4

-5

2684 10121416182022242628

TOTAL OUTPUT ERROR

vs. SUPPLY VOLTAGE

MAX4373 toc04

SUPPLY VOLTAGE (V)

OUTPUT ERROR (%)

AV = +50V/V

AV = +20V/V

AV = +100V/V

VSENSE = 6.25mV

-2.5

-2.0

-1.5

-1.0

-0.5

0.5

1.0

1.5

05025 75 100 125 150

TOTAL OUTPUT ERROR

vs. SENSE VOLTAGE

MAX4373 toc05

VSENSE (mV)

OUTPUT ERROR (%)

AV = +50V/V

AV = +20V/V

AV = +100V/V

VCC = +5.5V

-2.0

-1.5

-1.0

-0.5

0.5

1.0

1.5

2.0

05025 75 100 125 150

TOTAL OUTPUT ERROR

vs. SENSE VOLTAGE

MAX4373 toc06

VSENSE (mV)

OUTPUT ERROR (%)

AV = +50V/V

AV = +100V/V AV = +20V/V

1.0

0.5

2.0

1.5

2.5

3.0

0507525 100 125 150

TOTAL OUTPUT ERROR

vs. SENSE VOLTAGE

MAX4373 toc07

VSENSE (mV)

OUTPUT ERROR (%)

AV = +50V/V

AV = +20V/V

AV = +100V/V

VCC = +28V

-2

2684 10121416182022242628

TOTAL OUTPUT ERROR

vs. COMMON-MODE VOLTAGE

MAX4373 toc08

COMMON-MODE VOLTAGE (V)

OUTPUT ERROR (%)

AV = +50V/V

AV = +100V/V

AV = +20V/V

INPUT

OUTPUT

20μs/div

200mV

600mV

30mV

10mV

SMALL-SIGNAL PULSE RESPONSE

(AV = +20V/V)

MAX4373 toc09

INPUT

OUTPUT

20μs/div

500mV

1.5V

30mV

10mV

SMALL-SIGNAL PULSE RESPONSE

(AV = +50V/V)

MAX4373 toc10

INPUT

OUTPUT

20μs/div

30mV

10mV

SMALL-SIGNAL PULSE RESPONSE

(AV = +100V/V)

MAX4373 toc11

Typical Operating Characteristics (continued)

(VRS+ = +12V, VCC = +12V, RLOAD = 1MΩ, VRESET = 0V, VSENSE = 100mV, VPULL-UP = +5V, RPULL-UP = 10kΩ, TA= +25°C, unless

otherwise noted.)

MAX4373/MAX4374/MAX4375 Low-Cost, Micropower, High-Side

Current-Sense Amplifier +

Comparator + Reference ICs

Maxim Integrated | 6www.maximintegrated.com

INPUT

OUTPUT

20μs/div

150mV

50mV

LARGE-SIGNAL PULSE RESPONSE

(AV = +20V/V)

MAX4373 toc12

INPUT

OUTPUT

20μs/div

2.5V

7.5V

150mV

50mV

LARGE-SIGNAL PULSE RESPONSE

(AV = +50V/V)

MAX4373 toc13

INPUT

OUTPUT

20μs/div

500mV

9.5V

95mV

5mV

LARGE-SIGNAL PULSE RESPONSE

(AV = +100V/V)

MAX4373 toc14

-10

-100

10 100 1k 10k 100k

COMMON-MODE REJECTION

vs. FREQUENCY

-50

-60

-70

-80

-90

MAX4373 toc15

FREQUENCY (Hz)

CMR (dB)

-40

-30

-20

-10

-100

10 100 1k 10k 100k

POWER-SUPPLY REJECTION

vs. FREQUENCY

-50

-60

-70

-80

-90

MAX4373 toc16

FREQUENCY (Hz)

PSR (dB)

-40

-30

-20

-5

-2

-3

-4

-1

1k 100k10k 1000k

SMALL-SIGNAL GAIN

vs. FREQUENCY

MAX4373 toc17

FREQUENCY (Hz)

GAIN (dB)

AV = +50V/V

AV = +100V/V

AV = +20V/V

-5

1k 10k 100k

LARGE-SIGNAL GAIN

vs. FREQUENCY

-3

-4

MAX4373 toc18

FREQUENCY (Hz)

GAIN (dB)

-1

-2

VIN = 100mVP-P (20, 50)

VIN = 50mVP-P (100)

AV = +50V/V

AV = +20V/V

AV = +100V/V

Typical Operating Characteristics (continued)

(VRS+ = +12V, VCC = +12V, RLOAD = 1MΩ, VRESET = 0V, VSENSE = 100mV, VPULL-UP = +5V, RPULL-UP = 10kΩ, TA= +25°C, unless

otherwise noted.)

f1. f1

MAX4373/MAX4374/MAX4375 Low-Cost, Micropower, High-Side

Current-Sense Amplifier +

Comparator + Reference ICs

Maxim Integrated | 7www.maximintegrated.com

VCC

OUTPUT

100μs/div

POWER-UP DELAY

MAX4373 toc19

AV = +20V/V

OUTPUT

VCC

COMPARATOR POWER-UP DELAY

MAX4373 toc20

VCC = VPULL-UP

10µs/div

590

593

592

591

594

595

596

597

598

599

600

0105 15202530

COMPARATOR TRIP POINT vs.

SUPPLY VOLTAGE

MAX4373 toc21

SUPPLY VOLTAGE (V)

TRIP POINT (mV)

INPUT

125mV/div

OUTPUT

2.5V/div

2μs/div

COMPARATOR PROPAGATION DELAY

MAX4373 toc22

VOD = 5mV

2.4

2.2

2.8

3.0

2.6

3.4

3.6

3.2

3.8

08040 120 16020 10060 140 180 200

COMPARATOR PROPAGATION DELAY

vs. OVERDRIVE VOLTAGE

MAX4373 toc24

OVERDRIVE VOLTAGE (mV)

PROGAGATION DELAY (μs)

-50 -10 10-30 30507090

COMPARATOR PROPAGATION DELAY

vs. TEMPERATURE

MAX4373 toc26

TEMPERATURE (°C)

PROPAGATION DELAY (μs)

VOD = 5mV

Typical Operating Characteristics (continued)

(VRS+ = +12V, VCC = +12V, RLOAD = 1MΩ, VRESET = 0V, VSENSE = 100mV, VPULL-UP = +5V, RPULL-UP = 10kΩ, TA= +25°C, unless

otherwise noted.)

E wdqgoim:

MAX4373/MAX4374/MAX4375 Low-Cost, Micropower, High-Side

Current-Sense Amplifier +

Comparator + Reference ICs

Maxim Integrated | 8www.maximintegrated.com

0.8

1.2

1.0

1.6

1.4

1.8

2.0

010155 202530

COMPARATOR RESET VOLTAGE

vs. SUPPLY VOLTAGE

MAX4373 toc27

SUPPLY VOLTAGE (V)

RESET VOLTAGE (V)

0 0.6 0.80.2 0.4 1.0 1.2 1.4 1.6

COMPARATOR VOL vs. ISINK

MAX4373 toc28

ISINK (mA)

VOL (mV)

INPUT

OUTPUT

10μs/div

750mV

250mV

COMPARATOR AC RESPONSE

MAX4373 toc31

0.2

0.6

0.4

0.8

1.0

-60 -20 0-40 20406080100

TOTAL OUTPUT ERROR

vs. TEMPERATURE

MAX4373 toc33

TEMPERATURE (°C)

TOTAL OUTPUT ERROR (%)

-60 -20 0-40 20406080100

SUPPLY CURRENT

vs. TEMPERATURE

MAX4373 toc32

TEMPERATURE (°C)

SUPPLY CURRENT (μA)

MAX4374

MAX4375

MAX4373

VSENSE = 5mV

595

597

596

599

598

601

600

602

604

603

605

-60 -20 0-40 20406080100

COMPARATOR TRIP POINT

vs. TEMPERATURE

MAX4373 toc35

TEMPERATURE (°C)

COMPARATOR TRIP POINT (mV)

0.2

0.6

0.4

0.8

1.0

-60 -20 0-40 20406080100

GAIN ACCURACY

vs. TEMPERATURE

MAX4373 toc34

TEMPERATURE (°C)

GAIN ACCURACY (%)

AV = +20V/V, +50V/V

AV = +100V/V

Typical Operating Characteristics (continued)

(VRS+ = +12V, VCC = +12V, RLOAD = 1MΩ, VRESET = 0V, VSENSE = 100mV, VPULL-UP = +5V, RPULL-UP = 10kΩ, TA= +25°C, unless

otherwise noted.)otherwise noted.)

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MAX4373/MAX4374/MAX4375 Low-Cost, Micropower, High-Side

Current-Sense Amplifier +

Comparator + Reference ICs

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FUNCTION

Detailed Description

The MAX4373 high-side current-sense supervisor fea-

tures a high-side current-sense amplifier, bandgap ref-

erence, and comparator with latching output to monitor

a supply for an overcurrent condition (Figure 1). The

latching output allows the comparator to shut down a

power supply without oscillations. The MAX4374/

MAX4375 offer an additional comparator to allow win-

dow detection of the current.

Current-Sense Amplifier

The internal current-sense amplifier features a 0V to

+28V input common-mode range that is independent of

the supply voltage. With this feature, the device can

monitor the output current of a battery in deep dis-

charge and also high-side current-sensing voltages

exceeding VCC.

The current-sense amplifier is also suitable for low-side

current sensing. However, the total output voltage error

will increase when VRS+ falls below 2V, as shown in

the

Electrical Characteristics

and

Typical Operating

Characteristics

Pin Description

Figure 1. Functional Diagram

FUNCTIONNAME

11 VCC

2 2 OUT

3 3 CIN1

— 4 CIN2

— 7 COUT2

6 8 COUT1

5 6 RESET

45GND

— — N.C.

810 RS+

7 9 RS-

Supply Voltage Input

3, 6, 9, 12

MAX4374/MAX4375

Voltage Output. VOUT is proportional to VSENSE (VRS+ - VRS-).

MAX4373

Comparator Input 1. Positive input of an internal comparator. The nega-

tive terminal is connected to a 0.6V internal reference.

Comparator Input 2. Terminal of a second internal comparator. The pos-

itive terminal for the MAX4374 and the negative terminal for the

MAX4375. The other terminal is connected to a 0.6V internal reference.

Open-Drain Comparator Output. Output of the second unlatched inter-

nal comparator.

Open-Drain Comparator Output. Latching output of the comparator con-

trolled by CIN1. Connect RESET to GND to disable the latch.

Reset Input. Resets the output latch of the comparator at CIN1.

µMAX

Ground

µMAX/SO SO

No Connection. Not internally connected.

Power Connection to the External Sense Resistor

Load-Side Connection for the External Sense Resistor

RS-RS+

OUT

CIN2

GND

CIN1

LOAD

VIN = 0 TO 28V

VCC

RESET

0.6V

BANDGAP

REFERENCE

RSENSE

+ VSENSE -

VPULL-UP

(UP TO 5V) R2

R1 R4

VPULL-UP

(UP TO 5V)

MAX4374

(MAX4375)

R3 COUT1

COUT2

CURRENT-

SENSE

AMPLIFIER

+(-)

-(+)

GOOmV reference The positive terminal is accessible at CIN1. When RESET is high. the internal latch is active. and once (3th rises above GOOmV, the output latches into the open state. Rulsihg RESET low for 1.5us resets the latch. and holding RESET loW makes the latch transparent See RESETatPoWer-Up section The MAX4374/MAX4375 contain an additional open- drain comparator. The negative terminal of the MAX4374‘s additional comparator and the positive ter- minal of the MAX4375’s additional comparator are con- nected to the internal GOOmV reference as shown in Figure 1 The positive terminal of the MAX4374’s addi- tional comparator and the negative terminal of the MAX4375’s additional comparator are accessible at CIN2. Applications Information Recommended Component Values ldeally, the maximum load current Will develop the full- scale sense voltage across the current-sense resistor Choose the gain version needed to yield the maximum output voltage required for the application. Where VSENSE is the full-scale sense voltage. 150mV for gains of +20V/V and +50V/V or 100mV for a gain of +100V/V. Av is the gain of the device The minimum supply voltage is VOUT + 0.25V Note that the output for the gain of +1OOV/V is internally clamped at 12V Calculate the maximum value for RsENSE so that the differential voltage across RS+ and RS- does not exceed the full-scale sense voltage Choose the highest value resistance possible to maxi- mize VSENSE and thus minimize total output error ln applications monitoring high current. ensure that RSENSE is able to dissipate its oWn l2R loss. If the resis- tor‘s 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 Use resistors specified for current-sens- ing applications. vMWmaximintegratedcom ilh é RSo RS mun our MAX4373 Cth til—’vvv ‘ W t i lwi Overcurrent Protection Circuit The overcurrent protection circuit. shown in Figure 2 uses the MAX4373 to control an external P-chahne MOSFET. The MOSFET controlled by the MAX4373 opens the current path under overload conditions. The latched output of the MAX4373’s comparator prevents the circuit from oscillating. and the pushbutton resets the current path after an overcurreht condition. Window Detection Circuit Figure 3 shows a simple circuit suitable for window detection Let IOVER be the minimum load curreh (iLOAD) required to cause a low state at COUTZ, and |e IUNDEH be the maximum load current required to cause a high state at COUTt. where Av is the gain of the device and VREF is the inter- nal reference voltage (0.6V typ). Connect COUTt and COUT2. the resulting comparator output will be high when the current is inside the cur- rent window and low when the current is outside the Window. The Window is defined as load currents less than lot/ER and greater than luNDER Maxim Inlegrated l ti]

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Internal Comparator(s)

The MAX4373/MAX4374/MAX4375 contain an open-

drain output comparator for current limiting. The com-

parator’s negative terminal is connected to the internal

600mV reference. The positive terminal is accessible at

CIN1. When RESET is high, the internal latch is active,

and once CIN1 rises above 600mV, the output latches

into the open state. Pulsing RESET low for 1.5µs resets

the latch, and holding RESET low makes the latch

transparent. See

RESET at Power-Up

section

The MAX4374/MAX4375 contain an additional open-

drain comparator. The negative terminal of the

MAX4374’s additional comparator and the positive ter-

minal of the MAX4375’s additional comparator are con-

nected to the internal 600mV reference as shown in

Figure 1. The positive terminal of the MAX4374’s addi-

tional comparator and the negative terminal of the

MAX4375’s additional comparator are accessible at

CIN2.

Applications Information

Recommended Component Values

Ideally, the maximum load current will develop the full-

scale sense voltage across the current-sense resistor.

Choose the gain version needed to yield the maximum

output voltage required for the application:

where VSENSE is the full-scale sense voltage, 150mV for

gains of +20V/V and +50V/V or 100mV for a gain of

+100V/V. AVis the gain of the device. The minimum

supply voltage is VOUT + 0.25V. Note that the output for

the gain of +100V/V is internally clamped at 12V.

Calculate the maximum value for RSENSE so that the

differential voltage across RS+ and RS- does not

exceed the full-scale sense voltage:

Choose the highest value resistance possible to maxi-

mize VSENSE and thus minimize total output error.

In applications monitoring high current, ensure that

RSENSE is able to dissipate its own I2R loss. If the resis-

tor’s 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. Use resistors specified for current-sens-

ing applications.

Overcurrent Protection Circuit

The overcurrent protection circuit, shown in Figure 2,

uses the MAX4373 to control an external P-channel

MOSFET. The MOSFET controlled by the MAX4373

opens the current path under overload conditions. The

latched output of the MAX4373’s comparator prevents

the circuit from oscillating, and the pushbutton resets

the current path after an overcurrent condition.

Window Detection Circuit

Figure 3 shows a simple circuit suitable for window

detection. Let IOVER be the minimum load current

(ILOAD) required to cause a low state at COUT2, and let

IUNDER be the maximum load current required to cause

a high state at COUT1:

where AVis the gain of the device and VREF is the inter-

nal reference voltage (0.6V typ).

Connect COUT1 and COUT2; the resulting comparator

output will be high when the current is inside the cur-

rent window and low when the current is outside the

window. The window is defined as load currents less

than IOVER and greater than IUNDER.

RS-RS+

OUT

CIN1

LOAD

MAX4373

GND

COUT1

RESET

PUSHBUTTON

VCC

2.7V TO 5.5V

Figure 2. MAX4373 Overcurrent Protection Circuit

VVA

OUT SENSE V

=×

SENSE MAX

LOAD

SENSE MAX

()

and

UNDER REF

SENSE V

OVER REF

SENSE V

⎛

⎝

⎜⎞

⎠

⎟

⎛

⎝

⎜⎞

⎠

⎟

RS+ RSV .ig van :2 N ru 28V i Vac um % MAX4375 CiNZ R CiNi moi i iﬁ 2 iih Power-Supply Bypassing It is recommended that VCC be bypassed to GND at least a 0 WP ceramic capacitor to isoiate the ICf suppiy voltage transients It is possible that piugg in/out a battery or AC adapter/charger couid ca iarge fast iine transients (>5V/ps) at VCC The simp solution is to run VCC from a better reguiated sup (+5V for example), since Vcc and RS+ (or RS-) do have to be connected together For high-speed VCC transientsi another soiution i add a resistor in series with the Vcc pin and a O capacitor to create an RC time constant to slow the time of the transient. Since these current-sense am tiers consume iess than 100w; even a 2 5k§2 resi oniy drops an extra 250mV at VCC. For most appl tions with fast transients th in coniunction Wit 0 WP bypass capacitor works weii wwwmaximmtegratedcom

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Power-Supply Bypassing

It is recommended that VCC be bypassed to GND with

at least a 0.1µF ceramic capacitor to isolate the IC from

supply voltage transients. It is possible that plugging

in/out a battery or AC adapter/charger could cause

large, fast line transients (>5V/µs) at VCC. The simplest

solution is to run VCC from a better regulated supply

(+5V for example), since VCC and RS+ (or RS-) do not

have to be connected together.

For high-speed VCC transients, another solution is to

add a resistor in series with the VCC pin and a 0.1µF

capacitor to create an RC time constant to slow the rise

time of the transient. Since these current-sense ampli-

fiers consume less than 100µA, even a 2.5kΩresistor

only drops an extra 250mV at VCC. For most applica-

tions with fast transients, 1kΩin conjunction with a

0.1µF bypass capacitor works well.

RESET at Power-Up

The RESET pin is used to control the latch function of

comparator 1. Holding RESET low (<0.8V) makes the

latch transparent and COUT1 will respond to changes

at CIN1, above and below the internal 600mV reference

threshold voltage. When RESET is high (>2.0V), once

CIN1 rises above 600mV, COUT1 latches into the

open-drain OFF state and remains in this state even if

CIN1 drops below 600mV. Pulsing RESET low for at

least 1.5µs resets the latch.

There is no internal circuitry to control the reset function

during power-up. To prevent false latching, RESET

must be held low until the VCC power has risen above

the 2.7V minimum operating supply voltage. This is

easily accomplished when RESET is driven under µC or

logic gate control. However, if RESET is to be always

connected high, add an RC between VCC, RESET and

GND (see Figure 2). Note that RESET cannot exceed

VCC + 0.3V or +12V, whichever is less.

The following formula can be used to determine the

appropriate RC value.

where T is the maximum time for VCC to reach 2.7V and

0.8V is the maximum RESET logic low voltage. For

example, a 470kΩresistor and 0.22µF capacitor will

keep RESET low during a power-up time of up to 36ms.

A faster power-up time is also safe with the calculated

R and C since the capacitor will have even less time to

charge.

RC T

VV V

=−

()

ln . /( . . ) .2 7 2 7 0 8 0 3514

RS-RS+

OUT

CIN1

CIN2

LOAD

VCC = 2.7V TO 28V

VIN = 0 TO 28V

MAX4375

GND

VCC

GND R5

RSENSE

+ VSENSE -

COUT1

COUT2

ILOAD

RESET

VPULL-UP

(UP TO 5V)

Figure 3. MAX4375 Window Detector

WWI—\ﬂﬂﬂﬂ LILILILILILILI ﬂﬂﬂﬂ Ll |_l Ll Ll ﬂﬂﬂﬂﬂ LILILILILI www.maximimegrated.comlgackaggs 21 -0041 90-0096 21-0036 90-0092 21-0061 90-0330 21 -0041 90-0096

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Current-Sense Amplifier +

Comparator + Reference ICs

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Chip Information

SUBSTRATE CONNECTED TO GND

Ordering Information (continued)

PART TEMP RANGE PIN-

PACKAGE

GAIN

(V/V)

MAX4374TEUB+ -40°C to +85°C 10 µMAX +20

MAX4374TESD+ -40°C to +85°C 14 SO +20

MAX4374FEUB+ -40°C to +85°C 10 µMAX +50

MAX4374FESD+ -40°C to +85°C 14 SO +50

MAX4374HEUB+ -40°C to +85°C 10 µMAX +100

MAX4374HESD+ -40°C to +85°C 14 SO +100

MAX4375TEUB+ -40°C to +85°C 10 µMAX +20

MAX4375TESD+ -40°C to +85°C 14 SO +20

MAX4375FEUB+ -40°C to +85°C 10 µMAX +50

MAX4375FESD+ -40°C to +85°C 14 SO +50

MAX4375HEUB+ -40°C to +85°C 10 µMAX +100

MAX4375HESD+ -40°C to +85°C 14 SO +100

µMAX SO

µMAX/SO

RS+

RS-

COUT1

COUT2

CIN2

CIN1

OUT

VCC

GND

RS+

RS-

N.C.

COUT1

CIN1

N.C.

OUT

VCC

COUT2

N.C.

GND

N.C.

CIN2

COUT1

GND

RS+

RS-

OUT

CIN1

VCC

TOP VIEW

MAX4374

MAX4375

MAX4374

MAX4375

MAX4373

RESET RESET RESET

Pin Configurations

Denotes a lead(Pb)-free/RoHS-compliant package.

PACKAGE

TYPE

PACKAGE

CODE

OUTLINE

NO.

LAND

PATTERN NO.

8 SOIC S8+2 21-0041 90-0096

8 µMAX U8+1 21-0036 90-0092

10 µMAX U10+2 21-0061 90-0330

14 SOIC S14+1 21-0041 90-0096

Package Information

For the latest package outline information and land patterns (foot-

prints), 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.

MAX4373/MAX4374/MAX4375 Low-Cost, Micropower, High-Side

Current-Sense Amplifier +

Comparator + Reference ICs

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.

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.

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