Datasheet MAX 4070 AUA Datasheet (FREI)

AVAILABLE

For pricing, delivery, and

ordering information, please contact Maxim Direct

at 1-888-629-4642, or visit Maxim’s website at www.maximintegrated.com.

General Description

The MAX4069–MAX4072 low-cost, bidirectional, high­side, current-sense amplifiers are ideal for monitoring
battery charge and discharge currents in notebooks,
cell phones, and other portable equipment. They fea­ture up to 24V input common-mode voltage range, low
100µA supply current (which drops to only 10µA in
shutdown), and a total output error of less than 1.5%.
The wide 1.35V to 24V input common-mode range is
independent of the supply voltage, ensuring that the
current-sense feedback remains accurate even when
connected to a battery pack in deep discharge.

To achieve maximum flexibility, an external current-sense
resistor is used along with a Gain Select pin to choose
either 50V/V or 100V/V. A single output pin continuously
monitors the transition from charge to discharge and
avoids the need for a separate polarity output. The
MAX4070 contains an internal 2.5V reference. The
charging current is represented by an output voltage
from 2.5V to V

CC

, while discharge current is given from

2.5V to GND. The MAX4071 is similar, but with a refer­ence voltage of 1.5V. The MAX4069 has an adjustable
reference voltage, set by two external resistors. The
MAX4072 has an input for an external reference.

The MAX4069/MAX4071/MAX4072 operate from a 2.7V to
24V single supply. The MAX4070 operates from a 3.6V to
24V single supply. All devices are specified over the
automotive operating temperature range, -40°C to
+125°C. The MAX4070/MAX4071/MAX4072 are available
in 8-pin µMAX and 8-pin thin QFN packages. The
MAX4069 is available in a 10-pin µMAX

®

package.

Applications

Notebook Fuel Gauging

Smart-Battery Packs/Chargers

Motor Control

Power-Management Systems

Cell-Phone Battery-Current Monitoring

Features

♦ Bidirectional, Compact, Current-Sense Solution

♦ Total Output Error Less than 1.5%

♦ Selectable Gain of 50V/V or 100V/V

♦ Wide 1.35V to 24V Common-Mode Range

Independent of Supply Voltage

♦ 2.7V to 24V Single-Supply Operation

♦ Internal Precision Reference

Adjustable (MAX4069)

2.50V (MAX4070)

1.50V (MAX4071)

♦ Low 100µA Supply Current

♦ 10µA Supply Current in Shutdown

♦ Available in Space-Saving Packages

8-Pin Thin QFN (MAX4070/MAX4071/MAX4072)
8-Pin µMAX (MAX4070/MAX4071MAX4072)
10-Pin µMAX (MAX4069)

Bidirectional, High-Side, Current-Sense

Amplifiers with Reference

Ordering Information

MAX4070

V

BATT

= 1.35V TO 24V

VCC = 3.6V TO 24V

FROM BATTERY

CHARGER

R

SENSE

LOAD

TO ADC

2.5V

V

CC

GSEL

GND

RS- RS+

REFOUT

OUT

SHDN

Typical Operating Circuit

Pin Configurations and Selector Guide appear at end of
data sheet.

*

EP = Exposed pad.

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

19-2423; Rev 3; 11/08

MAX4069–MAX4072

PART TEMP RANGE PIN-PACKAGE

MAX4069AUB -40°C to +125°C 10 µMAX —

MAX4070AUA -40°C to +125°C 8 µMAX —

MAX4070ATA -40°C to +125°C 8 Thin QFN-EP* ABN

MAX4071AUA -40°C to +125°C 8 µMAX —

MAX4071ATA -40°C to +125°C 8 Thin QFN-EP* ABO

MAX4072AUA -40°C to +125°C 8 µMAX —

MAX4072ATA -40°C to +125°C 8 Thin QFN-EP* ABP

TOP

MARK

Bidirectional, High-Side, Current-Sense
Amplifiers with Reference

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

(V

RS

+

= V

RS

-

= V

CC

= 2.7V to 24V, V

SENSE

= V

RS

+

- V

RS

-

= 0V, I

REFOUT

= 0, V

SHDN

= VCC, V

GSEL

= GND, V

REFIN

= 2.5V (MAX4072),

T

A

= T

MIN

to T

MAX

, unless otherwise noted. Typical values are at TA= +25°C and at VCC= V

RS

+

= 12V.) (Notes 1, 2)

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 +26V

OUT to GND....................-0.3V to Lesser of (V

CC

+ 0.3V) or 15V

Differential Input Voltage (V

RS

+

- V

RS

-

) ..............................±0.3V

GSEL, SHDN, REFOUT, REFIN

and ADJ to GND.....................................-0.3V to (V

CC

+ 0.3V)

OUT Short-Circuit Duration to GND

or to Lesser of (V

CC

or 15V)...................................Continuous

REFOUT Short Circuit to V

CC

or GND........................Continuous

Current into Any Pin ..........................................................±20mA

Continuous Power Dissipation (T

A

= +70°C)

8-Pin µMAX (derate 4.5 mW/°C above +70°C) ............362mW

8-Pin Thin QFN (derate 24.4mW/°C above +70°C) ...1951mW

10-Pin µMAX (derate 5.6 mW/°C above +70°C) .......444.4mW

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

MAX4069–MAX4072

2

Maxim Integrated

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Operating Voltage Range
(Note 3)

Input-Referred Offset Voltage
(Note 5)

V

CC

V

OS

Common-Mode Input Range CMVR Guaranteed by CMRR test 1.35 24 V

Common-Mode Rejection Ratio CMRR 1.35V ≤ V

Supply Current I

Shutdown Supply Current I

CC

CC SHDN

Leakage Current V

Input Bias Current I

Recommended Full-Scale Sense
Voltage (Note 6)

RS+, IRS-

V

SENSE

MAX4069/MAX4071/MAX4072 (Note 4) 2.7 24

MAX4070 3.6 24

V

= V

CC

RS-

CC

A

CC

= V

= T

= V

RS+

= 12V

RS+ = VRS-

RS+

MIN

RS+

to T

V

V
T

V
SHDN = GND, T

V

= V

CC

RS+

SHDN = GND

= V

RS+

RS-

V

= V

CC

RS+

Gain = 50V/V 75

Gain = 100V/V 50

TA = +25°C 0.08 0.25

=

TA = -40°C to +85°C 0.8

T

= T

A

≤ 24V, V

= V

= 24V, RL = open,

RS-

MAX

= V

= 5.5V,

RS-

= +25°C

A

= V

= 24V,

RS-

to T

MIN

MAX

= 12V 100 120 dB

CC

100 250 µA

9

10 30

1

= 24V, VCC = 0V 0.1 0.5 µA

= V

= 24V 0 2.4 5 µA

RS-

V

mV

µA

mV

Bidirectional, High-Side, Current-Sense

Amplifiers with Reference

ELECTRICAL CHARACTERISTICS (continued)

(V

RS

+

= V

RS

-

= V

CC

= 2.7V to 24V, V

SENSE

= V

RS

+

- V

RS

-

= 0V, I

REFOUT

= 0, V

SHDN

= VCC, V

GSEL

= GND, V

REFIN

= 2.5V (MAX4072),

T

A

= T

MIN

to T

MAX

, unless otherwise noted. Typical values are at TA= +25°C and at VCC= V

RS

+

= 12V.) (Notes 1, 2)

MAX4069–MAX4072

Maxim Integrated

3

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Total OUT Voltage Error (Note 7)

V

SENSE

V

CC

gain = 50

V

SENSE

V

CC

gain = 100

MAX4069/MAX4070/
MAX4072:
V

SENSE

V

CC

gain = 50

MAX4069/MAX4070/
MAX4072:
V

SENSE

V

CC

gain = 100

= V

= V

= V

= V

= 75mV,

= 12V,

RS+

= 50mV,

= 12V,

RS+

= -35mV,

= 12V,

RS+

= -17.5mV,

= 12V,

RS+

TA = +25°C ±0.25 ±1.0

TA = - 40°C to + 85°C ±1.5

T

= T

MIN

to T

MAX

A

TA = +25°C ±0.25 ±1.0

TA = - 40°C to + 85°C ±1.5

T

= T

MIN

to T

MAX

A

TA = +25°C ±0.4 ±1.0

TA = - 40°C to + 85°C ±2.0

TA = T

MIN

to T

MAX

TA = +25°C ±0.8 ±2.0

TA = - 40°C to + 85°C ±4.0

= T

MIN

to T

MAX

T

A

±2.0

±2.5

±3.0

%

±6

MAX4071:
V

= -15mV,

SENSE

= V

V

CC

RS+

gain = 50

MAX4071:
V

= -7.5mV,

SENSE

= V

V

CC

RS+

gain = 100

V

= 3mV,

SENSE

V

= 12V , V

C C

= 12V,

= 12V,

= 12V

RS +

TA = +25°C ±1.0 ±2.5

TA = - 40°C to + 85°C ±4.0

T

= T

MIN

to T

MAX

A

±6.0

TA = +25°C ±2.0 ±5

TA = - 40°C to + 85°C ±10

T

= T

A

T

A

to T

MIN

MAX

= +25°C ±3

±15

Bidirectional, High-Side, Current-Sense
Amplifiers with Reference

ELECTRICAL CHARACTERISTICS (continued)

(V

RS

+

= V

RS

-

= V

CC

= 2.7V to 24V, V

SENSE

= V

RS

+

- V

RS

-

= 0V, I

REFOUT

= 0, V

SHDN

= VCC, V

GSEL

= GND, V

REFIN

= 2.5V (MAX4072),

T

A

= T

MIN

to T

MAX

, unless otherwise noted. Typical values are at TA= +25°C and at VCC= V

RS

+

= 12V.) (Notes 1, 2)

MAX4069–MAX4072

4

Maxim Integrated

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

OUT Voltage High V

OUT Voltage Low V

CC

- V

OL

-3dB Bandwidth BW

Gain A

Capacitive-Load Stability 100 pF

Power-Supply Rejection Ratio PSRR

Logic Low Voltage (GSEL, SHDN)VILVCC = 3.6V or 24V 0.6 V
Logic High Voltage (GSEL, SHDN)VIHVCC = 3.6V or 24V 2 V

Gain-Select Input Current I

Shutdown Input Current I

GSEL

SHDN

I

OUT

V

SENSE

V

RS+

I

OUT

V

SENSE

V

RS+

= 10µA,

= 100mV,

= V

= 500µA,

= 100mV,

= V

CC

CC

MAX4071,
V

= 2.7V

CC

MAX4069/MAX4070/
MAX4072,
V

= 3.6V

CC

MAX4071,

= 2.7V

V

CC

MAX4069/MAX4070/
MAX4072,
V

= 3.6V

CC

65 150

65 150

90 250

90 250

MAX4071,
V

= 2.7V

I

= -10µA,

OUT

V

= -100mV,

SENSE

= V

V

RS+

CC

I

= -500µA,

OUT

= -100mV,

V

SENSE

V

= V

RS+

CC

V

= 50mV,

SENSE

V

= 12V, CL = 100pF

CC

CC

MAX4069/MAX4070/
MAX4072,
V

= 3.6V

CC

MAX4071,

= 2.7V

V

CC

100 250

MAX4069/MAX4070/
MAX4072,
V

= 3.6V

CC

100 250

Gain = 50V/V 100

Gain = 100V/V 40

GSEL = GND 50

GSEL = V

V

CC

CC

= 2.7V to 24V
(MAX4069/MAX4071/MAX4072),
V

= 3.6V to 24V (MAX4070)

CC

100 120 dB

100

520

520

V

OH

GSEL = VCC = 24V or GND 0.01 1 µA

SHDN = V
SHDN = GND, V

= 24V 3 12

CC

= 24V 0.01 1

CC

mV

mV

kHz

V/V

µA

Bidirectional, High-Side, Current-Sense

Amplifiers with Reference

ELECTRICAL CHARACTERISTICS (continued)

(V

RS

+

= V

RS

-

= V

CC

= 2.7V to 24V, V

SENSE

= V

RS

+

- V

RS

-

= 0V, I

REFOUT

= 0, V

SHDN

= VCC, V

GSEL

= GND, V

REFIN

= 2.5V (MAX4072),

T

A

= T

MIN

to T

MAX

, unless otherwise noted. Typical values are at TA= +25°C and at VCC= V

RS

+

= 12V.) (Notes 1, 2)

Note 1: All devices are 100% tested at TA= +25°C. Limits over temperature are guaranteed by design.
Note 2: R1 = 215kΩ, R2 = 210kΩ for the MAX4069 only (see

Functional Diagram

). This sets REFOUT to 2.49V nominal.

Note 3: Guaranteed by the PSRR test.
Note 4: The REFOUT voltage for the MAX4069 should be set such that it does not exceed V

CC

- 1.1V. Similarly, the maximum REFIN

voltage for the MAX4072 should also be less than V

CC

- 1.1V.

Note 5: Input-Referred Offset Voltage is defined as the voltage difference between OUT and REFOUT, divided by the selected gain

of either 50 or 100, when V

SENSE

= V

RS+

- V

RS-

= 0V.

Note 6: The negative full-scale sense voltage is limited by the voltage range of OUT from V

REFOUT

to GND.

Note 7: Total OUT Voltage Error is the sum of offset voltage and gain errors. The output voltage is measured relative to the reference

(REFOUT or REFIN).

MAX4069–MAX4072

Maxim Integrated

5

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

REFOUT (MAX4069/MAX4070/MAX4071)

Reference Output Voltage V

Reference Output Voltage
Temperature Coefficient

Load Regulation

Line Regulation

TCV

ΔV

REFOUT

/ΔI

ΔV

ΔV

REF

REF I

REF/

REF Capacitive-Load Stability 500 pF

Reference Adjust Voltage
Threshold

V

ADJ

Reference Output Voltage Range

Reference Adjust Input Current I

ADJ

REFIN (MAX4072 only)

Input-Voltage Range VCC = 12V 1 4 V

Input Current REFIN = 2.5V, VCC = 12V -60 +20 µA

MAX4069,

= 12V

V

CC

(Note 2)

MAX4070,
V

= 12V

CC

MAX4071,

= 12V

V

CC

REFVCC

CC

= 12V

I

= 0 to 500µA 2

REFOUT

= 0 to -100µA 4

REFOUT

2.7V ≤ VCC ≤ 24V 20 µV/V

MAX4069, V

CC

MAX4069, range adjustable with R1

= 12V

V

CC

MAX4069, VCC = 12V, V

TA = +25°C 2.44 2.49 2.54

= T

MIN

to T

MAX

T

A

2.39 2.59

TA = +25°C 2.45 2.5 2.55

= T

MIN

to T

MAX

T

A

2.40 2.60

TA = +25°C 1.47 1.5 1.53

= T

MIN

to T

MAX

T

A

1.44 1.56

-40°C ≤ TA ≤ +85°C15

T

= T

MIN

to T

MAX

A

20

= 12V 1.230 V

and R2,

V

ADJ

to

+4

= 1.23V 100 nA

ADJ

V

ppm/°C

mV/mA

V

Bidirectional, High-Side, Current-Sense
Amplifiers with Reference

Typical Operating Characteristics

(V

CC

= V

RS+

= 12V, V

SENSE

= 50mV for gain of 100V/V and 75mV for gain of 50V/V, TA = +25°C, unless otherwise noted.)

MAX4069

REFOUT vs. TEMPERATURE

MAX4069-72 toc09

TEMPERATURE (°C)

REFOUT (V)

1007525 500-25

1.205

1.210

1.215

1.220

1.225

1.230

1.235

1.240

1.245

1.250

1.200

-50 125

REFOUT CONNECTED TO ADJ

SUPPLY CURRENT vs. TEMPERATURE

MAX4069-72 toc08

TEMPERATURE (°C)

SUPPLY CURRENT (μA)

1007550250-25

60

80

100

120

140

160

180

40

-50 125

AV = 50V/V

VCC = 24V

VCC = 12V

SUPPLY CURRENT vs. SUPPLY VOLTAGE

MAX4069-72 toc07

SUPPLY VOLTAGE (V)

SUPPLY CURRENT (μA)

22204 6 8 12 14 1610 18

70

80

90

100

110

120

130

140

60

224

AV = 100V/V

MAX4071

MAX4070

MAX4069

MAX4072

TOTAL ERROR vs. TEMPERATURE

MAX4069-72 toc06

TEMPERATURE (°C)

TOTAL ERROR (%)

1007550250-25

-1.0

-0.5

0

0.5

1.0

1.5

-1.5

-50 125

V

SENSE

= 50mV

A

V

= 100V/V

VCC = 24V

VCC = 12V

TOTAL ERROR vs. SUPPLY VOLTAGE

(V

SENSE

= 3mV)

MAX4069-72 toc05

SUPPLY VOLTAGE (V)

TOTAL ERROR (%)

1814610

-1.5

-1.0

-0.5

0

0.5

1.0

1.5

2.0

-2.0
222

AV = 100V/V

AV = 50V/V

TOTAL ERROR vs. SUPPLY VOLTAGE

MAX4069-72 toc04

SUPPLY VOLTAGE (V)

TOTAL ERROR (%)

222016 188 10 12 146

-0.4

-0.3

-0.2

-0.1

0

0.1

0.2

0.3

0.4

0.5

-0.5
424

V

SENSE

= 75mV

A

V

= 50V/V

V

SENSE

= 50mV

A

V

= 100V/V

(V

OUT

- V

REF

) vs. V

SENSE

MAX4069-72 toc03

V

SENSE

(V)

(V

OUT

- V

REF

) (V)

225200150 17550 75 100 12525

1

2

3

4

5

6

7

8

9

10

11

12

0

0 250

AV = 100V/V

AV = 50V/V

INPUT OFFSET VOLTAGE

vs. TEMPERATURE

MAX4069-72 toc02

TEMPERATURE (°C)

INPUT OFFSET VOLTAGE (μV)

1007525 500-25

-125

-100

-75

0

25

50

75

100

125

150

-150

-50 125

-50

-25

AV = 100V/V

INPUT OFFSET VOLTAGE DISTRIBUTION

MAX4069-72 toc01

VOS (μV)

PERCENTAGE OF UNITS (%)

160

120

80

40

0

-40

-80

-120

5

10

15

20

25

0

-160

200

-200

30

35

MAX4069–MAX4072

6

Maxim Integrated

Bidirectional, High-Side, Current-Sense

Amplifiers with Reference

Typical Operating Characteristics (continued)

(V

CC

= V

RS+

= 12V, V

SENSE

= 50mV for gain of 100V/V and 75mV for gain of 50V/V, TA = +25°C, unless otherwise noted.)

0

-140

0.01 1 100.1 100

PSRR AND CMRR vs. FREQUENCY

MAX4069-72 toc18

FREQUENCY (Hz)

PSRR AND CMRR (dB)

-100

-80

-60

-40

-20

-120

CMRR

PSRR

SMALL-SIGNAL GAIN

vs. FREQUENCY

MAX4069-72 toc17

FREQUENCY (kHz)

GAIN (dB)

100101

-15

-10

-5

0

5

-20

0.1 1000

AV = 50V/V

AV = 100V/V

VOL vs. TEMPERATURE

MAX4069-72 toc16

TEMPERATURE (°C)

V

OL

(mV)

1007525 500-25

25

50

75

100

125

150

175

200

225

250

0

-50 125

IL = 500μA

IL = 10μA

VOH vs. TEMPERATURE

MAX4069-72 toc15

TEMPERATURE (°C)

V

OH

(mV)

1007525 500-25

20

40

60

80

100

120

140

160

180

200

0

-50 125

VOH = VCC - V

OUT

IL = 500μA

IL = 10μA

MAX4071

REFOUT vs. SUPPLY VOLTAGE

MAX4069-72 toc14

SUPPLY VOLTAGE (V)

REFOUT (V)

1814106

1.496

1.497

1.498

1.499

1.500

1.501

1.502

1.495
222

MAX4070

REFOUT vs. SUPPLY VOLTAGE

MAX4069-72 toc13

SUPPLY VOLTAGE (V)

REFOUT (V)

222016 186 8 10 12 144

2.491

2.492

2.493

2.494

2.495

2.496

2.497

2.498

2.499

2.500

2.490
224

MAX4069

REFOUT vs. SUPPLY VOLTAGE

MAX4069-72 toc12

SUPPLY VOLTAGE (V)

REFOUT (V)

222016 186 8 10 12 144

1.217

1.219

1.221

1.223

1.225

1.227

1.229

1.231

1.233

1.235

1.215
224

MAX4071

REFOUT vs. TEMPERATURE

MAX4069-72 toc11

TEMPERATURE (°C)

REFOUT (V)

1007525 500-25

1.480

1.485

1.490

1.495

1.500

1.505

1.510

1.515

1.520

1.525

1.475

-50 125

MAX4070

REFOUT vs. TEMPERATURE

MAX4069-72 toc10

TEMPERATURE (°C)

REFOUT (V)

1007550250-25

2.465

2.480

2.495

2.510

2.525

2.540

2.450

-50 125

MAX4069–MAX4072

Maxim Integrated

7

Bidirectional, High-Side, Current-Sense
Amplifiers with Reference

Typical Operating Characteristics (continued)

(V

CC

= V

RS+

= 12V, V

SENSE

= 50mV for gain of 100V/V and 75mV for gain of 50V/V, TA = +25°C, unless otherwise noted.)

EXITING SHUTDOWN

MAX4069-72 toc24

100μs/div

V

REFOUT

2V/div

V

OUT

2V/div

V

SHDN

5V/div

STARTUP DELAY

MAX4069-72 toc23

20μs/div

V

REFOUT

5V/div

V

OUT

5V/div

V

CC

10V/div

LARGE-SIGNAL TRANSIENT RESPONSE

MAX4069-72 toc22

100μs/div

OUTPUT
2V/div

INPUT
20mV/div

GAIN = 100

REF

LARGE-SIGNAL TRANSIENT RESPONSE

MAX4069-72 toc21

100μs/div

OUTPUT
2V/div

INPUT
50mV/div

GAIN = 50

REF

SMALL-SIGNAL TRANSIENT RESPONSE

MAX4069-72 toc20

100μs/div

OUTPUT
500mV/div

REF

INPUT
5mV/div

GAIN = 100

SMALL-SIGNAL TRANSIENT RESPONSE

MAX4069-72 toc19

100μs/div

OUTPUT
200mV/div

REF

INPUT
5mV/div

GAIN = 50

MAX4069–MAX4072

8

Maxim Integrated

Bidirectional, High-Side, Current-Sense

Amplifiers with Reference

Functional Diagram

Pin Description

MAX4069–MAX4072

Maxim Integrated

9

PIN

MAX4069

111SHDN

2 2 2 RS- Negative Connection to the External Sense Resistor

3 3 3 RS+ Positive Connection to the External Sense Resistor

4 — — N.C. No Connection. Not internally connected.

5 4 4 GND

6 — — ADJ

7 5 — REFOUT Reference Output Voltage (MAX4069/MAX4070/MAX4071)

8 6 6 OUT

977V

10 8 8 GSEL

— — 5 REFIN Reference Input Voltage (MAX4072)

MAX4070/

MAX4071

MAX4072

NAME FUNCTION

Shutdown Input. Drive SHDN low to select shutdown mode. Connect SHDN
to V

for normal operation.

CC

Ground. For thin QFN packages, also make an external connection from
GND to the under-side exposed paddle.

Adjustable Output Voltage Feedback Input. Connect a resistor-divider
between REFOUT, ADJ, and GND (MAX4069 only, see Functional Diagram).

Voltage Output. The difference voltage, V
the voltage difference between RS+ and RS- and indicates the correct
polarity.

Supply Voltage Input. Bypass VCC to GND with a 0.1µF capacitor.

CC

Gain-Setting Input. Connect GSEL low to select gain = 50V/V, or connect
GSEL high to select gain = 100V/V.

OUT

- V

, is proportional to

REF

LOAD

FROM BATTERY

CHARGER

R

SENSE

GAIN SELECT

SHUTDOWN

2.7V TO 24V

V

RS+

RS-

GSEL

SHDN

CC

MAX4069

OA

OUT TO ADC

REFOUT

ADJ

R1

R2

CSA

GND

V

REF

1.23V

Detailed Description

The MAX4069–MAX4072 bidirectional, high-side, cur­rent-sense amplifiers are ideal for portable equipment.
The wide 1.35V to 24V input common-mode voltage
range is independent of the supply voltage, ensuring
that the current-sense feedback remains accurate even
when connected to a battery pack in deep discharge.

The MAX4069/MAX4071/MAX4072 operate from a 2.7V
to 24V single supply. Because the MAX4070 has a 2.5V
internal reference, it operates from 3.6V to 24V. All
devices have a low 100µA supply current that reduces
to only 10µA (typ) in shutdown mode. To achieve maxi­mum flexibility, an external current-sense resistor is
used along with a gain select pin (GSEL) to choose
either 50V/V or 100V/V. Drive GSEL low to select gain of
50V/V or drive GSEL high to choose gain of 100V/V
(see

Functional Diagram

). The MAX4069 has an
adjustable reference voltage set by two external resis­tors between REFOUT and ADJ, and GND pins. The
MAX4070 contains an internal 2.5V reference. The
MAX4071 is similar to the MAX4070 but with a fixed
internal reference voltage of 1.5V. The MAX4072 has a
reference input pin to allow use of external references.
Charging current is represented by an output voltage
from the reference voltage to VCC, while discharge cur­rent is given from the reference voltage to GND. The
direction of V

SENSE

is totally arbitrary.

The input stage of the MAX4069–MAX4072 is shown in
Figure 1. Its unique topology allows for monitoring bidi­rectional currents through the sense resistor (R

SENSE

). If,
for instance, current flows from RS+ to RS-, the
MAX4069–MAX4072 match for the voltage drop over the
external sense resistor (R

SENSE

) by increasing the cur­rent through the internal Q1 and RG1. At the same time,
the current through Q2 and RG2 decreases, however,
internal circuitry not shown in Figure 1 prevents Q2 from
turning off completely. Likewise, if current flows from RS­to RS+, the current through Q2 and RG2 increases and
the current through Q1 decreases. In this way, the volt­ages at the input terminals of the internal amplifier A1 are
kept constant and an accurate measurement of the sense
voltage is achieved. In the following amplifier stages of
the MAX4069–MAX4072, the output signal of amplifier A2
is level-shifted towards the reference voltage (V

REF

),
resulting in a voltage at the output pin (OUT) that swings
above the V

REF

voltage for positive-sense voltages and

below V

REF

for negative-sense voltages.

Applications Information

Bidirectional, Current-Sense Amplifier

Systems such as laptop computers and other devices
that have internal charge circuitry require a precise bidi­rectional, current-sense amplifier to accurately monitor
the battery’s current regardless of polarity. Figure 2
shows the MAX4069–MAX4072 used as a bidirectional
current monitor. In Figure 2, the direction of V

SENSE

is
assigned to charge and discharge, assuming charge is
greater than discharge. The practical choice of direction
is based on dynamic range at OUT, given that the range
of REF to VCCis usually greater than from REF to
ground. This is useful for implementing either smart bat­tery packs or fuel gauges.

High-Current Measurement

The MAX4069–MAX4072 can achieve high-current
measurements by using low-value sense resistors,
which can be paralleled to further increase the current­sense limit.

Adjusting V

REF

(MAX4069)

The MAX4069 has an output reference voltage that can
be set to a desired voltage by a two-resistor divider
between REFOUT, ADJ, and GND. If REFOUT and ADJ
are connected together, the minimum output reference
voltage is obtained, 1.23V (typ). The maximum voltage
for REFOUT is 4V (that requires VCC≥ 5.1V). The rec­ommended range for the external resistors is: R1 + R2
should be > 20kΩ and < 500kΩ.

Bidirectional, High-Side, Current-Sense
Amplifiers with Reference

Figure 1. Detailed Input Stage

Note: RG1= RG2= 104k (typ).

MAX4069–MAX4072

10

Maxim Integrated

R

Q1 Q2

SENSE

RS-RS+

RG2RG1

A1

MAX4069–MAX4072

OUT

I

OUT

A2

External Reference (MAX4072)

The MAX4072 contains REFIN pin for external refer­ence voltage. The allowable voltage range on REFIN is
1V (min) to 4V (max) with VCC≥ 5.1V.

Reference Output

(MAX4069/MAX4060/MAX4071)

The REFOUT of the MAX4069/MAX4070/MAX4071 can
sink 100µA and source 500µA. Keep the total capaci­tance on REFOUT under 500pF to maintain stability.

Recommended Component Values

Ideally, the maximum load current develops the full­scale sense voltage across the current-sense resistor.
Choose the gain needed to yield the maximum output
voltage required for the application:

V

OUT

= V

SENSE

x A

V

where V

SENSE

is the full-scale sense voltage, 75mV for
gain of 50V/V, or 50mV for gain of 100V/V. AVis the
gain of the device.

In applications monitoring high current, ensure that
R

SENSE

is able to dissipate its own I2R loss. If the resis­tor’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 maxi­mum ratings. Use resistors specified for current- sens­ing applications.

The MAX4069–MAX4072 sense a wide variety of cur­rents with different sense-resistor values. Table 1 lists
common resistor values for typical operation of these
devices. Listed output voltage is with respect to REF.

Sense Resistor, R

SENSE

Choose R

SENSE

based on the following criteria:

Voltage Loss: A high R

SENSE

value causes the power­source voltage to degrade through IR loss. For minimal
voltage loss, use the lowest R

SENSE

value.

Accuracy: A high R

SENSE

value allows lower currents
to be measured more accurately. This is because off­sets become less significant when the sense voltage is
larger. For best performance, select R

SENSE

to provide
approximately 75mV (gain of 50V/V) or 50mV (gain of
100V/V) of sense voltage for the full-scale current in
each application.

Efficiency and Power Dissipation: At high-current lev­els, the I2R losses in R

SENSE

can be significant. Take
this into consideration when choosing the resistor value
and its power dissipation (wattage) rating. Also, the
sense resistor’s value might drift if it is allowed to heat
up excessively.

Inductance: Keep inductance low if I

SENSE

has a large
high-frequency component. Wire-wound resistors have
the highest inductance, while metal film is somewhat
better. Low-inductance metal-film resistors are also
available. Instead of being spiral-wrapped round a

Bidirectional, High-Side, Current-Sense

Amplifiers with Reference

2

Figure 2. Bidirectional Current Monitor

MAX4069–MAX4072

Maxim Integrated

11

CELLS

I

I

DISCHARGE

RS- RS+

V

CC

GSEL

R

SENSE

MAX4070

CHARGE

OUT

LOAD

TO ADC

V

- V

OUT

REF

-25mV 25mV 50mV0

5V

2.5V

A

= 100

V

V

SENSE

CHARGE

CURRENT

GND

REFOUT

2.5V

SHDN

DISCHARGE

CURRENT

-2.5V

Bidirectional, High-Side, Current-Sense
Amplifiers with Reference

core, as in metal-film or wire-wound resistors, they are
a straight band of metal and are available in values
under 1Ω.

Peak Current: The maximum current through R

SENSE

must be limited to:

I

PEAK

= 0.3V / (R

SENSE

+ R

TRACE

)

where R

TRACE

is the total stray resistance from RS+

and RS- to R

SENSE

. To prevent forwarding the back-to­back diodes between the differential input, the absolute
maximum of the differential input voltage is 0.3V.

Dynamic Range Considerations

Although the MAX4069–MAX4072 have fully symmetri­cal, bidirectional, V

SENSE

input capability, the output­voltage range is usually higher from REF to VCCand
lower from REF to GND (unless the supply voltage is at
the lowest end of the operating range). Therefore, the
user must consider the dynamic range of current moni­tored in both directions and choose the supply voltage
and the reference voltage (REFOUT or REFIN) to make
sure the output swing above and below REF is ade­quate to handle the swings without clipping or running
out of headroom.

Shutdown Mode

When SHDN is low, the MAX4069–MAX4072 are shut
down and consume only 10µA. In shutdown mode,
OUT is high impedance and turns off. Connect SHDN
to VCCfor normal operation.

Power-Supply Bypassing

and Grounding

The MAX4069–MAX4072 do not require special
bypassing and respond quickly to transient changes in
line current. You can place a large capacitor at the RS­terminal (or “load” side) to decouple the load and,
thereby, reduce the current transients. These capaci­tors are not required for operation or stability and their
use does not degrade performance.

The MAX4069–MAX4072 have been designed as a high­side current monitor to ease the task of grounding any
battery charger, thermistor, etc., that may be a part of
the battery pack. Grounding these devices requires no
special precautions; follow the same cautionary steps
that apply to the system as a whole. High-current sys­tems can experience large voltage drops across a
ground plane, and this drop may add to or subtract from
V

OUT.

Using differential measurement between V

OUT

and REF prevents this problem. For highest current-mea­surement accuracy, use a single-point star ground.

On thin QFN packages, there is an exposed paddle that
does not carry any current, but should also be connect­ed to the ground plane for rated power dissipation.

Table 1. Recommended Component Values

MAX4069–MAX4072

12

Maxim Integrated

FULL-SCALE

CURRENT

(A)

0.075 50 75 3.75

0.05

0.75 50 75 3.75

0.5

3.75 50 75 3.75

2.5

7.5 50 75 3.75

5.0

15.0 50 75 3.75

10.0

CURRENT-SENSE

RESISTOR (mΩ)

1000

100

20

10

5

GAIN

(V/V)

100 50 5.0

100 50 5.0

100 50 5.0

100 50 5.0

100 50 5.0

V

SENSE

(mV)

FULL-SCALE OUTPUT

VOLTAGE WITH RESPECT

TO REF (V)

Layout

In order to dissipate sense-resistor heat from large
sense currents, solder the RS+ and the RS- pins to
large copper traces. Keep the part away from other
heat-generating devices.

For accurate measurement of V

SENSE

, the Kelvin
method is recommended. The current into RS+ and RS­is only a few microamps; therefore, a short distance from
RS+ and RS- pins does not cause significant errors. It is
recommended to keep the value of R

SENSE

reasonably

higher than the values of the trace’s resistance.

Bidirectional, High-Side, Current-Sense

Amplifiers with Reference

Pin Configurations

Chip Information

TRANSISTOR COUNT: 338

PROCESS: BiCMOS

Selector Guide

MAX4069–MAX4072

Maxim Integrated

13

TOP VIEW

SHDN

RS-

RS+

1

2

MAX4069

3

4

5

μMAX

10

GSEL

9

V

CC

OUT

8

REFOUTN.C.

7

ADJGND

6

1

SHDN

RS-

2

MAX4070
MAX4071

3

RS+

GND

(REFIN) FOR MAX4072 ONLY.

MAX4072

4

Thin QFN/μMAX

87GSEL

V

CC

OUT

6

REFOUT (REFIN)

5

SUPPLY

PART REFERENCE

MAX4069 ADJUSTABLE 2.7 to 24 1.35 to 24

MAX4070 2.5V 3.6 to 24 1.35 to 24

MAX4071 1.5V 2.7 to 24 1.35 to 24

MAX4072 EXTERNAL 2.7 to 24 1.35 to 24

VOLTAGE

RANGE (V)

COMMON-

MODE RANGE

(V)

Bidirectional, High-Side, Current-Sense
Amplifiers with Reference

Package Information

For the latest package outline information and land patterns, go to www.maxim-ic.com/packages.

PACKAGE TYPE PACKAGE CODE DOCUMENT NO.

8 TQFN-EP T833-2

21-0137

8 µMAX U8-1

21-0036

10 µMAX U10-2

21-0061

MAX4069–MAX4072

14

Maxim Integrated

6, 8, &10L, DFN THIN.EPS

Bidirectional, High-Side, Current-Sense

Amplifiers with Reference

Package Information (continued)

For the latest package outline information and land patterns, go to www.maxim-ic.com/packages.

MAX4069–MAX4072

Maxim Integrated

15

COMMON DIMENSIONS

SYMBOL MIN. MAX.

A 0.70 0.80

D 2.90 3.10

E 2.90 3.10

A1

0.00 0.05

L 0.20 0.40

0.25 MIN.k

A2 0.20 REF.

PACKAGE VARIATIONS

PKG. CODE N D2 E2 e JEDEC SPEC b

T633-2 6 1.50±0.10 2.30±0.10 0.95 BSC MO229 / WEEA 0.40±0.05 1.90 REF

T833-2 8 1.50±0.10 2.30±0.10 0.65 BSC MO229 / WEEC 0.30±0.05 1.95 REF

T833-3 8 1.50±0.10 2.30±0.10 0.65 BSC MO229 / WEEC 0.30±0.05 1.95 REF

1.50±0.10 MO229 / WEED-3

2.30±0.10 MO229 / WEED-3 2.00 REF0.25±0.050.50 BSC1.50±0.1010T1033-2

0.40 BSC - - - - 0.20±0.05 2.40 REFT1433-2 14 2.30±0.101.70±0.10

[(N/2)-1] x e

2.00 REF0.25±0.050.50 BSC2.30±0.1010T1033-1

2.40 REF0.20±0.05- - - - 0.40 BSC1.70±0.10 2.30±0.1014T1433-1

Bidirectional, High-Side, Current-Sense
Amplifiers with Reference

Package Information (continued)

For the latest package outline information and land patterns, go to www.maxim-ic.com/packages.

MAX4069–MAX4072

16

Maxim Integrated

α

8LUMAXD.EPS

α

Bidirectional, High-Side, Current-Sense

Amplifiers with Reference

Package Information (continued)

For the latest package outline information and land patterns, go to www.maxim-ic.com/packages.

MAX4069–MAX4072

Maxim Integrated

17

α

10LUMAX.EPS

α

Bidirectional, High-Side, Current-Sense
Amplifiers with Reference

Revision History

MAX4069–MAX4072

18

Maxim Integrated 160 Rio Robles, San Jose, CA 95134 USA 1-408-601-1000

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.

©

2008 Maxim Integrated

The Maxim logo and Maxim Integrated are trademarks of Maxim Integrated Products, Inc.

REVISION

NUMBER

3 11/08 Added information for RG1 and RG2 10

REVISION

DATE

DESCRIPTION

PAGES

CHANGED