Rainbow Electronics MAX9610 User Manual

General Description

The MAX9610 high-side current-sense amplifier offers precision accuracy specifications of VOSless than 500μV (max) and gain error less than 0.5% (max). This device features an ultra-low 1μA quiescent supply current. The MAX9610 fits in a tiny, 1mm x 1.5mm μDFN package or a 5-pin SC70 package, making this part ideal for applications in notebook computers, cell phones, cameras, PDAs, and all lithium-ion batteryoperated portable devices where accuracy, low quiescent current, and small size are critical.

The MAX9610 features an input voltage range (common mode) from 1.6V to 5.5V. This input range is excellent for monitoring the current of a single-cell, lithium-ion battery (Li+), which at full charge is 4.2V, typically 3.6V in normal use, and less than 2.9V when ready to be recharged. These current-sense amplifiers have a voltage output and are offered in three gain versions: 25V/V (MAX9610T), 50V/V (MAX9610F), and 100V/V (MAX9610H).

The three gain versions offer flexibility in the choice of the external current-sense resistor. The very low 500μV (max) input offset voltage allows small 25mV to 50mV full-scale V

SENSE

voltage for very low voltage drop at

full-load current measurement.

The MAX9610 is offered in tiny 6-pin μDFN, (1mm x

1.5mm x 0.8mm footprint) and 5-pin SC70 packages, specified for operation over the -40°C to +85°C temperature range.

For a very similar 1.6V to 28V input voltage device in a 4-bump UCSP™ package (1mm x 1mm x 0.6mm), refer to the MAX9938 data sheet.

Applications

Cell Phones

Cameras

Portable Li+ Battery Powered Systems

3.3V and 5V Power Management Systems

PDAs

USB Ports

Features

♦ Ultra-Low Supply Current of 1µA (max)

♦ Low 500µV (max) Input Offset Voltage

♦ Low < 0.5% (max) Gain Error

♦ Input Common Mode: +1.6V to +5.5V

♦ Voltage Output

♦ Three Gain Versions Available

25V/V (MAX9610T) 50V/V (MAX9610F) 100V/V (MAX9610H)

♦ Tiny µDFN (1mm x 1.5mm x 0.8mm) and

SC70 Packages

MAX9610

1µA, µDFN/SC70, Lithium-Ion Battery,

Precision Current-Sense Amplifier

________________________________________________________________

Maxim Integrated Products

19-4342; Rev 0; 10/08

For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642, or visit Maxim’s website at www.maxim-ic.com.

Pin Configurations appear at end of data sheet.

UCSP is a trademark of Maxim Integrated Products, Inc.

MAX9610

OUT

10kΩ

GND

OUT

ADC

μC

LOAD

= 3.3V

RS-

RS+

SENSE

LOAD

BATT

1.6V to 5.5V

Typical Operating Circuit

Ordering Information

PART*

PIN-

GAIN

(V/V)

TOP MARK

MAX9610TELT+T 6 μDFN 25 OU

MAX9610FELT+T 6 μDFN 50 OS

MAX9610HELT+T 6 μDFN 100 OT

MAX9610TEXK+T 5 SC70 25 ATG

MAX9610FEXK+T 5 SC70 50 ATE

MAX9610HEXK+T 5 SC70 100 ATF

All devices are specified over the -40°C to +85°C extended

temperature range.

Denotes a lead-free/RoHS-compliant package.

T = Tape and reel.

PACKAGE

MAX9610

1µA, µDFN/SC70, Lithium-Ion Battery, Precision Current-Sense Amplifier

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS

ELECTRICAL CHARACTERISTICS

RS+

= V

RS-

= 3.6V, V

SENSE

= (V

RS+

- V

RS-

) = 0, TA= -40°C to +85°C, 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.

RS+, RS- to GND......................................................-0.3V to +6V

OUT to GND .............................................................-0.3V to +6V

RS+ to RS- .............................................................................±6V

Short-Circuit Duration: OUT to GND or RS+ ..............Continuous

Continuous Input Current (Any Pin)..................................±20mA

Continuous Power Dissipation (T

= +70°C)

5-Pin SC70 (derate 3.1mW/°C above +70°C)..............247mW

6-Pin μDFN (derate 2.1mW/°C above +70°C) .............168mW

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

Package Reflow Soldering Temperature .........................+260°C

PARAMETER

CONDITIONS

UNITS

RS+

= 3.6V, TA = +25°C 0.6 1.0

RS+

= 3.6V, -40°C < TA < +85°C 1.4

RS+

= 5.5V, TA = +25°C

1.2

Supply Current (Note 2)

RS+

= 5.5V, -40°C < TA < +85°C 1.6

μA

Common-Mode Input Range V

Guaranteed by CMRR,

-40°C < T

< +85°C

1.6 5.5 V

Common-Mode Rejection Ratio CMRR

TA = +25°C, gain = 25, 50, 100 (Note 3)

Gain = 25, 50

Input Offset Voltage V

Gain = 100

μV

MAX9610T 25

MAX9610F 50Gain G

MAX9610H

V/V

TA = +25°C, gain = 25, 50, 100 (Note 4)

Gain = 25, 50

Gain Error GE

Gain = 100 ±1

Output Resistance R

OUT

TA = +25°C (Note 5) 7.0 10

kΩ

G = 25 2.5 15

G = 50 5 30

OUT Low Voltage V

G = 100 10 70

OUT High Voltage V

VOH = V

RS-

- V

OUT

(Note 6) 0.1 0.2 V

SYMBOL

MIN TYP MAX

0.75

1.6V < V

-40°C < TA < +85°C

< 5.5V, -40°C < TA < +85°C

RS+

104

±100 ±500

±600

±700

100

±0.1 ±0.5

±0.8

13.2

MAX9610

1µA, µDFN/SC70, Lithium-Ion Battery,

Precision Current-Sense Amplifier

_______________________________________________________________________________________ 3

PARAMETER

SYMBOL

CONDITIONS

MIN

TYP

MAX

UNITS

SENSE

= 50mV, G = 25

SENSE

= 50mV, G = 50

Small-Signal Bandwidth BW

SENSE

= 50mV, G = 100 60

kHz

Output Settling Time t

1% final value, V

SENSE

= 25mV 35 μs

Power-Up Time t

1% final value, V

SENSE

= 25mV

μs

ELECTRICAL CHARACTERISTICS (continued)

RS+

= V

RS-

= 3.6V, V

SENSE

= (V

RS+

- V

RS-

) = 0, TA= -40°C to +85°C, unless otherwise noted. Typical values are at TA= +25°C.)

(Note 1)

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

= +25°C. All temperature limits are guaranteed by design.

Note 2: V

OUT

= 0V. ICCis the total current into RS+ plus RS-.

Note 3: V

is extrapolated from measurements for the Gain Error test.

Note 4: Gain Error is calculated by applying two values of V

SENSE

and calculating the error of the slope, vs. the ideal:

G = 25: V

SENSE

20mV and 120mV

G = 50: V

SENSE

10mV and 60mV

G = 100: V

SENSE

5mV and 30mV

Note 5: The device is stable for any external capacitance value. Note 6: V

is the voltage from V

RS-

to V

OUT

with V

SENSE

= 3.6V/Gain.

Typical Operating Characteristics

RS+

= V

RS-

= 3.6V, TA= +25°C.)

-250

-200-150 -100 -50 0

25020015010050

MAX9610F

OFFSET VOLTAGE HISTOGRAM

MAX9610 toc01

OFFSET VOLTAGE (μV)

N (%)

-0.2

-0.15 -0.1 -0.05 0

0.20.150.10.05

MAX9610F

GAIN ACCURACY HISTOGRAM

MAX9610 toc02

GAIN ACCURACY (%)

N (%)

300

200

100

400

500

600

700

800

900

1000

-40 10-15 35 60 85

SUPPLY CURRENT

vs. TEMPERATURE

MAX9610 toc03

TEMPERATURE (°C)

SUPPLY CURRENT (nA)

5.5V

3.6V

1.6V

170

110

100

MAX9610

1µA, µDFN/SC70, Lithium-Ion Battery, Precision Current-Sense Amplifier

4 _______________________________________________________________________________________

Typical Operating Characteristics (continued)

RS+

= V

RS-

= 3.6V, TA= +25°C.)

SUPPLY CURRENT

vs. COMMON-MODE VOLTAGE

MAX9610 toc04

COMMON-MODE VOLTAGE (V)

SUPPLY CURRENT (μA)

4.64.13.1 3.62.62.1

0.10

0.20

0.30

0.40

0.50

0.60

0.70

0.80

0.90

1.00

1.6 5.5

100

-40 10-15 35 60 85

OFFSET VOLTAGE

vs. TEMPERATURE

MAX9610 toc05

TEMPERATURE (°C)

OFFSET VOLTAGE (μV)

1.6 2.62.1 3.1 3.6 4.1 4.6 5.1

5.5

OFFSET VOLTAGE

vs. COMMON-MODE VOLTAGE

MAX9610 toc06

COMMON-MODE VOLTAGE (V)

OFFSET VOLTAGE (μV)

GAIN ERROR vs. TEMPERATURE

MAX9610 toc07

TEMPERATURE (°C)

GAIN ERROR (%)

603510-15

0.07%

0.09%

0.11%

0.13%

0.15%

0.17%

0.19%

0.21%

0.23%

0.25%

0.05%

-40 85

-0.20%

-0.16%

-0.18%

-0.12%

-0.14%

-0.08%

-0.10%

-0.06%

-0.02%

-0.04%

1.6 2.6 3.12.1 3.6 4.1 4.6 5.1 5.5

GAIN ERROR

vs. COMMON-MODE VOLTAGE

MAX9610 toc08

COMMON-MODE VOLTAGE (V)

GAIN ERROR (%)

OUT

vs. V

SENSE

RS+

= 5.5V

MAX9610 toc09

SENSE

(mV)

OUT

(V)

20015010050

0.5

1.0

1.5

2.0

2.5

3.0

3.5

4.0

4.5

5.0

5.5

6.0

0 250

G = 25

G = 50

G = 100

0.8

0.6

0.4

0.2

1.0

1.2

1.6

1.4

1.8

010 4020 6050 7030 80

OUT

vs. V

SENSE

RS+

= 1.6V

MAX9610 toc10

SENSE

(mV)

OUT

(V)

G = 25

G = 50

G = 100

NORMALIZED GAIN

vs. FREQUENCY

MAX9610 toc11

FREQUENCY (kHz)

NORMALIZED GAIN (dB)

100101

-20

-15

-10

-5

-25

0.1 1000

G = 25

G = 50

G = 100

CMRR vs. FREQUENCY

MAX9610 toc12

FREQUENCY (Hz)

CMRR (dB)

10k1k100

-120

-100

-80

-60

-40

-20

-140 10 100k

MAX9610

1µA, µDFN/SC70, Lithium-Ion Battery,

Precision Current-Sense Amplifier

_______________________________________________________________________________________ 5

Typical Operating Characteristics (continued)

RS+

= V

RS-

= 3.6V, TA= +25°C.)

10μs/div

LARGE-SIGNAL RESPONSE

G = 50

50mV/div

1V/div

MAX9610 toc17

SENSE

OUT

10μs/div

LARGE-SIGNAL RESPONSE

G = 100

20mV/div

1V/div

MAX9610 toc18

SENSE

OUT

10μs/div

SMALL-SIGNAL RESPONSE

G = 100

5mV/div

200mV/div

MAX9610 toc15

SENSE

OUT

10μs/div

LARGE-SIGNAL RESPONSE

G = 25

100mV/div

1V/div

MAX9610 toc16

SENSE

OUT

10μs/div

SMALL-SIGNAL RESPONSE

G = 25

20mV/div

200mV/div

MAX9610 toc13

SENSE

OUT

10μs/div

SMALL-SIGNAL RESPONSE

G = 50

10mV/div

200mV/div

MAX9610 toc14

SENSE

OUT

MAX9610

1µA, µDFN/SC70, Lithium-Ion Battery, Precision Current-Sense Amplifier

6 _______________________________________________________________________________________

Detailed Description

The MAX9610 family of unidirectional high-side, current-sense amplifiers features a 1.6V to 5.5V input common-mode range. The input range is excellent for monitoring the current of a single-cell lithium-ion battery (Li+), which at full charge is 4.2V, typically 3.6V in normal use, and less than 2.9V when ready to be recharged. The MAX9610 is ideal for many batterypowered, handheld devices because it uses only 1μA quiescent supply current to extend battery life. The MAX9610 monitors current through a current-sense resistor and amplifies the voltage across that resistor. See the

Typical Operating Circuit

on page 1.

The MAX9610 is a unidirectional current-sense amplifier that has a well-established history. An op amp is used to force the current through an internal gain resistor at RS+ that has a value of R1, such that its voltage drop equals the voltage drop across an external sense resistor, R

SENSE

. There is an internal resistor at RS- with the same value as R1to minimize offset voltage. The current through R1is sourced by a pFET. Its drain current is the same as its source current that flows through a second gain resistor, R

OUT

. This produces an output

voltage, V

OUT

, whose magnitude is I

LOAD

x R

SENSE

OUT/R1

. The gain accuracy is based on the matching

of the two gain resistors R1and R

OUT

(see Table 1). Total gain = 25V/V for the MAX9610T, 50V/V for the MAX9610F, and 100V/V for the MAX9610H.

Applications Information

Choosing the Sense Resistor

Choose R

SENSE

based on the following criteria.

Voltage Loss

A high R

SENSE

value causes the power-source voltage to drop due to IR loss. For minimal voltage loss, use the lowest R

SENSE

value.

OUT Swing vs. V

RS+

and V

SENSE

The MAX9610 is unique since the supply voltage is the input common-mode voltage (the average voltage at RS+ and RS-). There is no separate VCCsupply voltage input. Therefore, the OUT voltage swing is limited by the minimum voltage at RS+.

OUT(MAX)

= V

RS+(MAX)

- V

SENSE(MAX)

- V

and

SENSE

full scale should be less than V

OUT

/gain at the

minimum RS+ voltage. For best performance with a

3.6V supply voltage, select R

SENSE

to provide approximately 120mV (gain of 25V/V), 60mV (gain of 50V/V), or 30mV (gain of 100V/V) of sense voltage for the fullscale current in each application. These can be increased by use of a higher minimum input voltage.

Accuracy

In the linear region (V

OUT

< V

OUT(MAX)

), there are two

components to accuracy: input offset voltage (V

) and Gain Error (GE). The MAX9610 has VOS= 500μV (max) and Gain Error of 0.5% (max). Use the following linear equation to calculate total error.

OUT

= (Gain ± GE) x V

SENSE

± (Gain x VOS)

A high R

SENSE

value allows lower currents to be measured more accurately because offsets are less significant when the sense voltage is larger.

Efficiency and Power Dissipation

At high current levels, the I2R loss 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. The precision VOSof the MAX9610 allows the use of small sense resistors to reduce power dissipation and reduce hot spots.

SENSE

OUT

LOAD

× (max)

Pin Description

µDFN

NAME

FUNCTION

1 1, 2 GND Ground

2, 5 — N.C.

No Connection. Not internally connected.

3 3 OUT Output

4 4 RS-

Load-Side Connection to External Sense Resistor

6 5 RS+

Power-Side Connection to External Sense Resistor

GAIN (V/V)

OUT

(Ω)

100 100 10k

50 200 10k

25 400 10k

Table 1. MAX9610, Internal Gain Setting Resistors (Typical Values)

SC70

R1 (Ω)

MAX9610

1µA, µDFN/SC70, Lithium-Ion Battery,

Precision Current-Sense Amplifier

_______________________________________________________________________________________ 7

Kelvin Connections

Because of the high currents that flow through R

SENSE

, take care to eliminate parasitic trace resistance from causing errors in the sense voltage. Either use a four terminal current-sense resistor or use Kelvin (force and sense) PCB layout techniques.

Optional Output Filter Capacitor

When designing a system that uses a sample and hold stage in the analog-to-digital converter, the sampling capacitor momentarily loads OUT and causes a drop in the output voltage. If sampling time is very short (less than a microsecond), consider using a ceramic capacitor across OUT and GND to hold V

OUT

constant during sampling. This also decreases the small-signal bandwidth of the current-sense amplifier and reduces noise at OUT.

Typical Application Circuit

Bidirectional Application

Battery-powered systems may require a precise bidirectional current-sense amplifier to accurately monitor the battery’s charge and discharge currents. Measurements of the two separate outputs with respect to GND yield an accurate measure of the charge and discharge currents, respectively (Figure 1).

MAX9610

OUT

GND

OUTOUT

ADC

LOAD

RS-

RS+

SENSE

LOAD

BATT

= 1.6V TO 5.5V

MAX9610

OUT

GND

RS-

RS+

MICRO-

CONTROLLER

VDD = 3.3V

TO WALL-CUBE/ CHARGER

Figure 1. Bidirectional Application

MAX9610

1µA, µDFN/SC70, Lithium-Ion Battery, Precision Current-Sense Amplifier

8 _______________________________________________________________________________________

Chip Information

PROCESS: BiCMOS

123

654

RS+ RS-N.C.

GND OUTN.C.

MAX9610T/F/H

1mm x 1.5mm μDFN

TOP VIEW (PINS ON BOTTOM)

GND

RS-

OUT

RS+

GND

MAX9610T/F/H

2mm x 2.2mm SC70

TOP VIEW

(DIAGRAMS NOT TO SCALE.)

Pin Configurations

MAX9610

1µA, µDFN/SC70, Lithium-Ion Battery,

Precision Current-Sense Amplifier

_______________________________________________________________________________________ 9

Package Information

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

PACKAGE TYPE PACKAGE CODE DOCUMENT NO.

6 μDFN L611+1

21-0147

5 SC70 X5+1

21-0076

TOP VIEW

SIDE VIEW

A 0.65

COMMON DIMENSIONS

PIN 1

0.075x45

BOTTOM VIEW

MIN.

SECTION A-A

A A

NOM.

0.72 0.80

MAX.

0.00

0.05

1.501.45D 1.55

1.000.95E 1.05

0.350.30L 0.40

--0.00

0.08

--0.05L2 0.10

0.200.17b 0.23

0.50 BSC.e

TOPMARK

-DRAWING NOT TO SCALE-

DOCUMENT CONTROL NO.APPROVAL

TITLE:

REV.

PACKAGE OUTLINE, 6L uDFN, 1.5x1.0x0.8mm

21-0147

PIN 1

MARK

L611-1, L611-2

Pkg. Code

0.20 --

6L UDFN.EPS

MAX9610

1µA, µDFN/SC70, Lithium-Ion Battery, Precision Current-Sense Amplifier

10 ______________________________________________________________________________________

-DRAWING NOT TO SCALE-

DOCUMENT CONTROL NO.APPROVAL

TITLE:

REV.

PACKAGE OUTLINE, 6L uDFN, 1.5x1.0x0.8mm

21-0147

2005 2006 2007 2008 2009 2010 2011 2012 2013 2014Calendar Year

Legend:

Marked with bar Blank space - no bar required

06-11Payweek 12-17 18-23 24-29 30-35 36-41 42-47 48-51 52-05

TABLE 2 Translation Table for Payweek Binary Coding

TABLE 1 Translation Table for Calendar Year Code

Legend: Marked with bar Blank space - no bar required

Package Information (continued)

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

MAX9610

1µA, µDFN/SC70, Lithium-Ion Battery,

Precision Current-Sense Amplifier

Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.

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

SC70, 5L.EPS

PACKAGE OUTLINE, 5L SC70

21-0076

Package Information (continued)

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

Rainbow Electronics MAX9610 User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual