DS2745U+ Datasheet DS2745U+ | P1-P3

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FEATURES

16-Bit Bidirectional Current Measurement

1.56V LSB, ±51.2mV Dynamic Range

104A LSB, ±3.4A Dynamic Range (RSNS =

15m)

Current Accumulation Register Resolution

6.25Vhr LSB, ±204.8mVh Range

0.417mAhr LSB, ±13.65Ah Range

(R

SNS

= 15m)

11-Bit Voltage Measurement

4.88mV LSB, 0V to 4.5V Input Range

11-Bit Temperature Measurement

0.125ºC Resolution, -20ºC to +70ºC

Industry Standard I

2

C Interface

Low Power Consumption:

Active Current:

70A typical, 100A max

Sleep Current:

1A typical, 3A max

BLOCK DIAGRAM

PIN CONFIGURATION

DESCRIPTION

The DS2745 provides current-flow, voltage, and

temperature measurement data to support battery-

capacity monitoring in cost-sensitive applications. The

DS2745 can be mounted on either the host side or

pack side of the application. Current measurement

and coulomb counting is accomplished by monitoring

the voltage drop across an external sense resistor,

voltage measurement is accomplished through a

separate voltage-sense input, and temperature

measurement takes place on-chip. A standard I

2

C

interface with software programmable address gives

the controlling microprocessor access to all data and

status registers inside the DS2745. A low-power sleep

mode state conserves energy when the cell pack is in

storage.

APPLICATIONS

Cellular

GPS

PDAs

Handheld Products

Table 1.

ORDERING INFORMATION

PART MARKING PIN-PACKAGE

DS2745U+

2745

MAX package

DS2745U+T&R

2745

DS2745U+ in Tape-and-Reel

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

DS2745

Low-Cost I

2

C Battery Monito

r

www.maxim-ic.com



MAX

SDA

VDD

VIN

CTG

VSS

SNS

PIO

SC

L

6

8

7

5

3

1

2

4

See Table 1 for Ordering Information.

19-4631

;

Rev 5/09

DS2745 Low-Cost I

2

C Battery Monitor

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ABSOLUTE MAXIMUM RATINGS*

Voltage on All Pins Relative to V

SS

-0.3V to +6V

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

Storage Temperature Range -55°C to +125°C

Soldering Temperature See IPC/JEDECJ-STD-020A

* This is a stress rating only and functional operation of the device at these or any other conditions above those indicated in the operation

sections of this specification is not implied. Exposure to absolute maximum rating conditions for extended periods of time may affect reliability.

RECOMMENDED DC OPERATING CONDITIONS

(2.5V  V

DD

 4.5V; T

A

= 0C to +70C.)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Supply Voltage V

DD

(Note 1) +2.5 +4.5 V

Serial Data I/O Pin SDA (Note 1) -0.3 +5.5 V

Serial Clock Pin SCL (Note 1) -0.3 +5.5 V

Programmable I/O Pin PIO (Note 1) -0.3 +5.5 V

VIN Pin V

IN

(Note 1) -0.3 V

DD

+0.3 V

DC ELECTRICAL CHARACTERISTICS

(2.5V  V

DD

 4.5V; T

A

= 0C to +70C, unless otherwise noted.)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

70 100

Active Current I

ACTIVE

V

DD

= 4.5V 105

A

Sleep-Mode Current I

SLEEP

SCL = SDA = V

SS

,

PIO = V

SS

1 3

A

Current Resolution I

LSB

1.56

V/R

Current Full-Scale

Magnitude

I

FS

(Note 1) 51.2 mV/R

Current Offset I

OERR

(Note 2) -7.82 +12.5

V/R

Current Gain Error I

GERR

-1.0 +1.0

% of

reading

Accumulated Current

Resolution

q

CA

6.25

Vh/R

Accumulated Current

Offset

q

OERR

V

SNS

= V

SS

, (Notes 4, 5) -188 +0

µVh/R

per day

Voltage Resolution V

LSB

4.88 mV

Voltage Full-Scale V

FS

0 4.992 V

Voltage Error V

GERR

(Note 12) -25 +25 mV

Temperature Resolution T

LSB

0.125 °C

Temperature Error T

ERR

-3 +3 ºC

Current Sample Clock

Frequency

f

SAMP

18.6 kHz

Timebase Accuracy t

ERR

V

DD

= 3.8V, T

A

= +25°C ±1

%

DS2745 Low-Cost I

2

C Battery Monitor

3 of 15

±2

-20°C ≤ T

A

≤ +70°C,

2.5V ≤ V

DD

≤ 4.5V

±3

Input Resistance, VIN R

IN

15

M

Input Logic High:

SCL, SDA, PIO

V

IH

(Note 1) 1.5 V

Input Logic Low:

SCL, SDA, PIO

V

IL

(Note 1) 0.6 V

Output Logic Low:

SDA, PIO

V

OL

I

OL

= 4mA (Note 1) 0.4 V

Pulldown Current: SCL,

SDA, PIO

I

PD

0.25

A

Input Capacitance: SCL,

SDA

C

BUS

50 pF

SLEEP Timeout t

SLEEP

(Note 3) 2.2 S

2-WIRE INTERFACE TIMING SPECIFICATIONS

(V

DD

= 2.5V to 4.5V, T

A

= -20C to +70C.)

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

SCL Clock Frequency

f

SCL

(Note 6) 0 400 KHz

Bus Free Time Between a

STOP and START Condition

t

BUF

1.3 µs

Hold Time (Repeated)

START Condition

t

HD:STA

(Note 7) 0.6 µs

Low Period of SCL Clock

t

LOW

1.3 µs

High Period of SCL Clock

t

HIGH

0.6 µs

Setup Time for a Repeated

START Condition

t

SU:STA

0.6 µs

Data Hold Time

t

HD:DAT

(Note 8, 9) 0 0.9 µs

Data Setup Time

t

SU:DAT

(Note 8) 100 ns

Rise Time of Both SDA and

SCL Signals

t

R

20 + 0.1C

B

300 ns

Fall Time of Both SDA and

SCL Signals

t

F

20 + 0.1C

B

300 ns

Setup Time for STOP

Condition

t

SU:STO

0.6 µs

Spike Pulse Widths

Suppressed by Input Filter

t

SP

(Note 10) 0 50 ns

Capacitive Load for Each

Bus

Line

C

B

(Note 11) 400 pF

SCL, SDA Input

Capacitance

C

BIN

60 pF

DS2745U+

DS2745U+

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