Datasheet ADM4073 Datasheet (ANALOG DEVICES)

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2

V

Low Cost, Voltage Output,

FEATURES

Low cost, compact, current-sense solution
Three available gain versions

20 V/V (ADM4073T)
50 V/V (ADM4073F)

100 V/V (ADM4073H)
Typical ±1.0% full-scale accuracy
500 μA supply current
Wide 1.8 MHz bandwidth
3 V to 28 V operating supply
Wide 2 V to 28 V common-mode range

Independent of supply voltage
Operates from −40°C to +125°C
Available in a 6-lead SOT-23 package
Pin-to-pin compatibility with the MAX4073

APPLICATIONS

Cell phones, PDAs
Notebook computers
Portable/battery-powered systems
Smart battery packs/chargers
Automotive
Power management systems
PA bias control
General system/board-level current monitoring
Precision current sources

High-Side, Current-Sense Amplifier

ADM4073

FUNCTIONAL BLOCK DIAGRAM

I

LOAD

R

RS+

RG1

ADM4073

CURRENT

MIRROR

I

RGD

GND

SENSE

I

RG1

AV

RS–

RG2

RGD = 12kΩ

2V TO 28V

3V TO 28V

0.1µF

V

CC

Figure 1.

APPLICATION DIAGRAM

R

V TO 28

3V TO 28V

0.1µF

SENSE

RS+

V

CC

ADM4073

RS–

OUT

V

OUT

ADC

V

OUT

05131-003

V

OUT

GENERAL DESCRIPTION

The ADM4073 is a low cost, high-side, current-sense amplifier
ideal for small portable applications such as cell phones,
notebook computers, PDAs, and other systems where current
monitoring is required. The device is available in three different
gain models, eliminating the need for gain-setting resistors.
Because the ground path is not interrupted, the ADM4073 is
particularly useful in rechargeable battery-powered systems,
while its wide 1.8 MHz bandwidth makes it suitable for use
inside battery-charger control loops. The input common-mode
range of 2 V to 28 V is independent of the supply voltage.

Rev. 0

Information furnished by Analog Devices is believed to be accurate and reliable. However, no
responsibility is assumed by Anal og Devices for its use, nor for any infringements of patents or ot her
rights of third parties that may result from its use. Specifications subject to change without notice. No
license is granted by implication or otherwise under any patent or patent rights of Analog Devices.
Trademarks and registered trademarks are the property of their respective owners.

GND

Figure 2.

The voltage on the output pin is determined by the current
flowing through the selectable external sense resistor and the
gain of the version selected. The operating range is 3 V to 28 V
with a typical supply current of 500 μA. The ADM4073 is
available in a 6-lead SOT-23 package and is specified over the
automotive operating temperature range (−40°C to +125°C).

One Technology Way, P.O. Box 9106, Norwood, MA 02062-9106, U.S.A.
Tel: [phone] www.analog.com
Fax: [phone] ©2006 Analog Devices, Inc. All rights reserved.

05131-001

ADM4073

TABLE OF CONTENTS

Features.............................................................................................. 1

ESD Caution...................................................................................4

Applications....................................................................................... 1

Functional Block Diagram .............................................................. 1

Application Diagram........................................................................ 1

General Description ......................................................................... 1

Revision History ............................................................................... 2

Specifications..................................................................................... 3

Absolute Maximum Ratings............................................................ 4

Thermal Characteristics .............................................................. 4

REVISION HISTORY

7/06—Revision 0: Initial Version

Pin Configuration and Function Descriptions..............................5

Typical Performance Characteristics..............................................6

Theory of Operation ...................................................................... 10

R

............................................................................................. 10

SENSE

Output (OUT)............................................................................. 10

Outline Dimensions....................................................................... 11

Ordering Guide .......................................................................... 11

Rev. 0 | Page 2 of 12

ADM4073

SPECIFICATIONS

V

= 2 V to 28 V, V

RS+

SENSE

= (V

RS+

− V

) = 0, VCC = 3 V to 28 V, TA = −40°C to +125°C, unless otherwise noted. Typical values are at TA = 25°C.

RS−

Table 1.

Parameter Min Typ Max Unit Conditions

POWER SUPPLY

Operating Voltage Range, VCC 3 28 V Inferred from PSRR test
Common-Mode Input Range, V
Common-Mode Input Rejection, CMR 90 dB V

2 28 V Inferred OUT voltage error test

CMR

= 100 mV, VCC = 12 V

SENSE

Supply Current, ICC 0.5 1.2 mA VCC = 28 V
Leakage Current, I
Input Bias Current, I
Input Bias Current, I
Full Scale Sense Voltage, V
Total Out Voltage Error

±1.0 ±5.0 % V

±1.0 ±5.0 % V
±5.0 % V

Extrapolated Input Offset Voltage, VOS 1.0 mV VCC = V
Out High Voltage (VCC − VOH) 0.8 1.2 V VCC = 3 V, V

0.8 1.2 V VCC = 7.5 V, V

0.8 1.2 V VCC = 15 V, V

0.05 2 μA VCC = 0 V, V

RS+/IRS−

20 60 μA

RS+

40 120 μA

RS−

150 mV V

SENSE

2

±1 % V

±5.0 % V

±7.5 % V

= (V

SENSE

= 100 mV, VCC = 12 V, V

SENSE

= 100 mV, VCC = 12 V, V

SENSE

= 100 mV, VCC = 12 V, V

SENSE

= 100 mV, VCC = 28 V, VRS = 28 V, TA = +25°C

SENSE

= 100 mV, VCC = 28 V, VRS = 28 V, TA = −40°C to +125°C

SENSE

= 6.25 mV,3 VCC = 12 V, VRS = 12 V

SENSE

RS+

= 28 V, TA = 85°C

RS+

− V

RS+

= 12 V, V

)

RS−

= 2 V

RS+

= 12 V, TA = +25°C

RS+

= 12V, TA = −40°C to +125°C

RS

> 10 mV

SENSE

= 150 mV (ADM4073T)

SENSE

= 150 mV (ADM4073F)

SENSE

= 150 mV (ADM4073H), TA = 25°C

SENSE

DYNAMIC CHARACTERISTICS

Bandwidth, BW 1.8 MHz V

1.7 MHz V

1.6 MHz V
600 kHz V

= 100 mV, VCC = 12 V, V

SENSE

= 100 mV, VCC = 12 V, V

SENSE

= 100 mV, VCC = 12 V, V

SENSE

= 6.25 mV,3 VCC = 12 V, V

SENSE

= 12 V, C

RS+

= 12 V, C

RS+

= 12 V, C

RS+

= 12 V, C

RS+

= 5 pF (ADM4073T)

LOAD

= 5 pF (ADM4073F)

LOAD

= 5 pF (ADM4073H)

LOAD

= 5 pF (ADM4073T/F/H)

LOAD

Gain, AV 20 V/V ADM4073T
50 V/V ADM4073F
100 V/V ADM4073H

Gain Accuracy, dAV ±1.0 ±2.0 %

±2.0 %

±1.0 ±1.5 %

±3.0 %

OUT Settling Time to 1% of Final Value 400 ns V

800 ns V

Output Resistance, R

12 kΩ

OUT

Power Supply Rejection Ratio, PSRR 78 dB V
85 dB V
90 dB V

Power-Up Time

Saturation Recovery Time

1

100% production tested at TA = 25°C. Specifications over temperature limit are guaranteed by design.

2

Total out voltage error is the sum of the gain and offset errors.

3

6.25 mV = 1/16th of 100 mV full-scale sense voltage.

4

Output settles to within 1% of final value.

5

The device does not experience phase reversal when overdriven.

4

5

5 μs C
5 μs C

= 10 mV to 150 mV, VCC = 12 V, V

V

SENSE

T

= +25°C (ADM4073T/F)

A

= 10 mV to 150 mV, VCC = 12 V, V

V

SENSE

= −40°C to +125°C (ADM4073T/F)

T

A

= 10 mV to 100 mV, V

V

SENSE

= +25°C (ADM4073H)

T

A

= 10 mV to 100 mV, VCC = 12 V, V

V

SENSE

T

= −40°C to +125°C (ADM4073H)

A

= 6.25 mV to 100 mV, V

SENSE

= 100 mV to 6.25 mV, V

SENSE

= 12 V, V

CC

= 12 V, V

CC

= 12 V, V

CC

= 60 mV, VCC = 3 V to 28 V (ADM4073T)

SENSE

= 24 mV, VCC = 3 V to 28 V (ADM4073F)

SENSE

= 12 mV, VCC = 3 V to 28 V (ADM4073H)

SENSE

= 5 pF, V

LOAD

= 5 pF, VCC = 12 V, V

LOAD

= 100 mV

SENSE

RS+

= 12 V

RS+

= 12 V,

RS+

RS+

RS+

= 12 V,

= 12 V,

= 12 V,

= 12 V, C

RS+

= 12 V, C

RS+

LOAD

LOAD

= 5 pF

= 5 pF

1

Rev. 0 | Page 3 of 12

ADM4073

ABSOLUTE MAXIMUM RATINGS

Table 2.

Parameter Rating

VCC to GND −0.3 V to +30 V
RS± to GND −0.3 V to +30 V
OUT to GND −0.3 V to (VCC + 0.3 V)
OUT Short-Circuit to GND Continuous
Differential Input Voltage (V
Current into any Pin ±20 mA
Storage Temperature Range −65°C to +125°C
Operating Temperature Range −40°C to +125°C
Lead Temperature, Soldering (10 sec)
Junction Temperature 150°C

RS+

− V

) ±5 V

RS−

300°C

ESD CAUTION

ESD (electrostatic discharge) sensitive device. Electrostatic charges as high as 4000 V readily accumulate on
the human body and test equipment and can discharge without detection. Although this product features
proprietary ESD protection circuitry, permanent damage may occur on devices subjected to high energy
electrostatic discharges. Therefore, proper ESD precautions are recommended to avoid performance
degradation or loss of functionality.

Stresses above those listed under Absolute Maximum Ratings
may cause permanent damage to the device. This is a stress
rating only; functional operation of the device at these or any
other conditions above those indicated in the operational
section of this specification is not implied. Exposure to absolute
maximum rating conditions for extended periods may affect
device reliability.

THERMAL CHARACTERISTICS

θJA is specified for the worst-case conditions, that is, a device
soldered in a circuit board for surface-mount packages.

Table 3. Thermal Resistance

Package Type θJA Unit

6-Lead SOT-23 169.5 °C/W

Rev. 0 | Page 4 of 12

ADM4073

G

G

A

PIN CONFIGURATION AND FUNCTION DESCRIPTIONS

DM4073xWRJ

ND

ND

1

TOP VIEW

2

(Not to Scal e)

OUT

6

RS–

5

3

V

CC

4

RS+

05131-002

Figure 3. Pin Configuration

Table 4. Pin Function Descriptions

Pin No. Mnemonic Description

1, 2 GND Chip Ground Pin.
3 VCC Chip Power Supply. Requires a 0.1μF capacitor to ground.
4 RS+ Power-Side Connection to the External Sense Resistor.
5 RS− Load-Side Connection to the External Sense Resistor.
6 OUT

Voltage Output. V

is proportional to V

OUT

. Output impedence is approximately 12 kΩ.

SENSE

Rev. 0 | Page 5 of 12

ADM4073

TYPICAL PERFORMANCE CHARACTERISTICS

0.60
V

= 6.25mV

SENSE

0.55

0.45

0.43

V

SENSE

= 6.25mV

0.50

ADM4073H

0.45

0.40

SUPPLY CURRENT (mA)

0.35

0.30

03

5 10152025

ADM4073T

SUPPLY VOLTAGE (V)

Figure 4. Supply Current vs. Supply Voltage (V

1.5
V

= 100mV

SENSE

1.4

1.3

1.2

1.1

1.0

0.9

0.8

SUPPLY CURRENT (mA)

0.7

0.6

0.5

5 10152025

03

SUPPLY VOLTAGE (V)

Figure 5. Supply Current vs. Supply Voltage (V

ADM4073F

SENSE

ADM4073H

ADM4073F

ADM4073T

SENSE

= 6.25mV)

= 100 mV)

0

05131-005

0

05131-006

0.41

0.39

SUPPLY CURRENT (mA)

0.37

0.35
030

5 10152025

Figure 7. Supply Current vs. RS+ Voltage (V

V

= 100mV

SENSE

1.5

1.3

1.1

0.9

SUPPLY CURRENT (mA)

0.7

0.5
030

5 10152025

Figure 8. Supply Current vs. RS+ Voltage (V

ADM4073H

ADM4073T

ADM4073F

V

(V)

RS+

= 6.25 mV)

SENSE

ADM4073H

ADM4073F

ADM4073T

V

(V)

RS+

= 100 mV)

SENSE

05131-008

05131-009

0.7
V

= 0mV

SENSE

= 28V

V

CC

0.6

0.5

0.4

0.3

0.2

SUPPLY CURRENT (mA)

0.1

0

–25 0 25 50 75 100 125

–50 150

TEMPERATURE (° C)

Figure 6. Supply Current vs. Temperature

05131-007

Rev. 0 | Page 6 of 12

1.0
V

= 100mV

SENSE

0.8

0.6

0.4

ADM4073T

0.2

0

–0.2

–0.4

TOTAL OUTPUT ERROR (%)

–0.6

–0.8

–1.0

03

5 10152025

Figure 9. Total Output Error vs. Supply Voltage (V

ADM4073F

ADM4073H

SUPPLY VOLTAGE (V)

= 100 mV)

SENSE

0

05131-010

ADM4073

1.0
V

= 6.25mV

SENSE

0.8

0.6

0.4

0.2

0

–0.2

–0.4

TOTAL OUTPUT ERROR (%)

–0.6

–0.8

–1.0

03

5 10152025

Figure 10. Total Output Error vs. Supply Voltage (V

ADM4073F

ADM4073T

ADM4073H

SUPPLY VOLTAGE (V)

= 6.25 mV)

SENSE

0

05131-011

2.0

1.5

1.0

0.5

0

–0.5

GAIN ACCURACY (%)

–1.0

–1.5

–2.0

–50 150

0 50 100

–25 25 75 125

TEMPERATURE (° C)

Figure 13. Gain Accuracy vs. Temperature

05131-014

1.0

0.5

0

–0.5

–1.0

–1.5

–2.0

TOTAL OUTPUT ERRO R (%)

–2.5

–3.0

03

5 10152025

COMMON-MO DE VOLTAGE (V)

ADM4073F

ADM4073H

ADM4073T

0

05131-012

Figure 11. Total Output Error vs. Common-Mode Voltage

0.10

0.08

0.06

0.04

0.02

0

–0.02

–0.04

TOTAL OUTPUT ERRO R (%)

–0.06

–0.08

–0.10

–50 150

0 50 100

VCC = 28V

VCC = 12V

TEMPERATURE (° C)

05131-013

1.4

1.2

1.0

(V)

0.8

OH

– V

0.6

CC

V

0.4

0.2

0

–50 150

Figure 14. O/P High Voltage (V

70

60

50

40

30

PSRR (dB)

20

10

0

0.1 10000

1 10 100 1000

Figure 12. Total Output Error vs. Temperature

ADM4073H

ADM4073F

ADM4073T

0 50 100

TEMPERATURE (° C)

− VOH) vs. Temperature

CC

ADM4073F

FREQUENCY (kHz)

Figure 15. PSRR vs. Frequency

ADM4073T

ADM4073H

05131-015

05131-016

Rev. 0 | Page 7 of 12

ADM4073

V

V

2

V

45

40

35

30

25

20

GAIN (dB)

15

10

5

0

0.1 10000

ADM4073H

ADM4073F

ADM4073T

1 10 100 1000

FREQUENCY (kHz)

Figure 16. Small Signal Gain vs. Frequency

100mV

V

SENSE

2.5mV/DIV

OUT

50mV/DI

1µs/DIV

05131-017

95mV

10V

9.5V

05131-020

Figure 19. ADM4073H Small Signal Transient Response

V

SENSE

2.5mV/DI

OUT

50mV/DIV

V

SENSE

2.5mV/DIV

OUT

125mV/DI

1µs/DIV

Figure 17. ADM4073T Small Signal Transient Response

100mV

95mV

2V

1.9V

100mV

95mV

5V

4.75V

100mV

V

SENSE

45mV/DIV

OUT

0.9V/DIV

05131-018

1µs/DIV

6.25mV

2V

0.120V

05131-021

Figure 20. ADM4073T Large Signal Transient Response

100mV

V

SENSE

45mV/DIV

OUT

2.35V/DIV

6.25mV

5V

0.3V

1µs/DIV

Figure 18. ADM4073F Small Signal Transient Response

05131-019

1µs/DIV

05131-022

Figure 21. ADM4073F Large Signal Transient Response

Rev. 0 | Page 8 of 12

ADM4073

V

6

V

2

V

V

100mV

VCC= 0V TO 4V

4V

V

SENSE

45mV/DIV

OUT

4.7V/DIV

V

SENSE

100mV/DI

00mV/DI

1µs/DIV

Figure 22. ADM4073H Large Signal Transient Response

VCC= 3V

OUT

1µs/DIV

Figure 23. ADM4073T Overdrive Response

6.25mV

10V

0.6V

250mV

50mV

V

OH

1V

V

CC

V/DI

OUT

1V/DI

05131-023

1µs/DIV

0V

2V

0V

05131-025

Figure 24. ADM4073T Start-Up Delay

05131-024

Rev. 0 | Page 9 of 12

ADM4073

V

()(

)

−+=

THEORY OF OPERATION

The current from the source flows through R
generates a voltage drop, V

, across the RS+ and RS−

SENSE

terminals of the sense amplifier. The Input Stage Amplifier A1
regulates its inputs to be equal, thereby shunting a current
proportional to V

SENSE/RG1

to the output current mirror. This
current is then multiplied by a gain factor b in the output stage
current mirror and flows through R
Therefore, V

is related to V

OUT

SENSE

to generate V

GD

by the ratio of R

the current gain b.

V

OUT

= AV × V

SENSE

where:

= RGD/R

A

V

G1

× b

where:

= 20 V/V (for ADM4073T).

A

V

A

= 50 V/V (for ADM4073H).

V

= 100 V/V (for ADM4073F).

A

V

I

LOAD

R

RS+

SENSE

RS–

2V TO 28V

SENSE

, which

.

OUT

to RGD and

G1

V

OUT

To measure lower currents accurately, as large a sense resistor
as possible should be used to utilize the higher end of the sense
voltage range. This reduces the effects of the offset voltage
errors in the internal amplifier.

When currents are very large, it is important to take the I

2

R
power losses across the sense resistor into account. If the sense
resistor’s rated power dissipation is not sufficient, its value can
drift, giving an inaccurate output voltage, or it could fail
altogether. This, in turn, causes the voltage across the RS+ and
RS− pins to exceed the absolute maximum ratings.

If the monitored supply rail has a large amplitude high
frequency component, a sense resistor with low inductance
should be chosen.

R

INPUT COPPER PCB T RACE OUT PUT

3V TO 28

0.1µF

SENSE

RS+

V

CC

ADM4073

RS–

OUT

I

RG1

MIRROR

I

RGD

GND

RG1

AV

ADM4073

RGD = 12kΩ

RG2

V

OUT

05131-003

3V TO 28V

0.1µF

V

CC

CURRENT

Figure 25. Functional Block Diagram

R

SENSE

The ADM4073 has the ability to sense a wide variety of
currents by selecting a particular sense resistor. Select a suitable
output voltage for full-scale current, for example, 10 V for 10 A.
Then select a gain model that gives the most efficient use of the
sense voltage range (150 mV max).

In the example above, using the ADM4073H (gain of 100) give
an output voltage of 10 V when the sense voltage is 100 mV.
Use the following equation to determine what value of sense
resistor gives 100 mV with 10 A flowing through it:

= 100 mV/10 A

R

SENSE

R

= 10 mΩ

SENSE

= (I

V

OUT

LOAD

× R

SENSE

) × A

V

GND

05131-004

Figure 26. Using PCB Trace for Current Sensing

OUTPUT (OUT)

The output stage of the ADM4073 is a current source driving a
pull-down resistance. To ensure optimum accuracy, care must
be taken not to load this output externally. To minimize output
errors, ensure OUT is connected to a high impedance input
stage. If this is not possible, output buffering is recommended.

The percent error introduced by output loading is determined
with the following formula:

LOAD

where:

R

is the external load applied to OUT.

LOAD

R

is the internal output resistance (12 kΩ).

OUT_INT

RRRError

_

INTOUT

SENSE

1/100%

Rev. 0 | Page 10 of 12

ADM4073

OUTLINE DIMENSIONS

2.90 BSC

4526

1.60 BSC

PIN 1

INDICATOR

1.30

1.15

0.90

0.15 MAX

1 3

1.90
BSC

0.50

0.30

2.80 BSC

0.95 BSC

1.45 MAX

SEATING
PLANE

0.22

0.08
10°

0.60

4°

0.45

0°

0.30

COMPLIANT TO JEDEC STANDARDS MO-178-AB

Figure 27. 6-Lead Small Outline Transistor Package [SOT-23]

(RJ-6)

Dimensions shown in millimeters

ORDERING GUIDE

Model Gain Temperature Range Package Description Package Option Branding

ADM4073TWRJZ-REEL7

ADM4073FWRJZ-REEL7

ADM4073HWRJZ-REEL7

1

Z = Pb-free part.

1

1

1

20

50

100

−40°C to +125°C

−40°C to +125°C

−40°C to +125°C

6-Lead SOT-23 RJ-6 M2E

6-Lead SOT-23 RJ-6 M2C

6-Lead SOT-23 RJ-6 M2D

Rev. 0 | Page 11 of 12

ADM4073

NOTES

©2006 Analog Devices, Inc. All rights reserved. Trademarks and
registered trademarks are the property of their respective owners.
D05131-0-7/06(0)

Rev. 0 | Page 12 of 12