LTC2990IMS_技术文档

LTC2990

2

I C Temperature,Voltage

and Current Monitor

FeaTures

DescripTion

The LTC^®2990 is used to monitor system temperatures,

n

Measures Voltage, Current and Temperature

2

n

Measures Two Remote Diode Temperatures

voltages and currents. Through the I C serial interface,

n

±±1C ꢀAAuraAc, 0.061C Resolution

the device can be conﬁgured to measure many combi-

nations of internal temperature, remote temperature,

n

±ꢁ1C ꢂnternal Temperature Sensor

n

14-Bit ADC Measures Voltage/Current

remote voltage, remote current and internal V . The

CC

n

3V to 5.5V Supply Operating Voltage

internal 10ppm/°C reference minimizes the number of

supporting components and area required. Selectable

address and conﬁgurable functionality give the LTC2990

ﬂexibility to be incorporated in various systems needing

temperature, voltage or current data. The LTC2990 ﬁts

well in systems needing sub-millivolt voltage resolution,

1% current measurement and 1°C temperature accuracy

or any combination of the three.

n

Four Selectable Addresses

n

Internal 10ppm/°C Voltage Reference

n

10-Lead MSOP Package

applicaTions

n

Temperature Measurement

n

L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear

Technology Corporation. All other trademarks are the property of their respective owners.

Supply Voltage Monitoring

n

Current Measurement

n

Remote Data Acquisition

n

Environmental Monitoring

Typical applicaTion

Voltage, Current, Temperature Monitor

Temperature Total Unadjusted Error

R

SENSE

1.0

2.5V

I

LOAD

5V

0.5

V

T

V1

V2

V3

CC

REMOTE

SDA

SCL

ADR0

ADR1

0

–0.5

–1.0

LTC2990

T

REMOTE

V4

2990 TA01a

GND

T

INTERNAL

MEASURES: TWO SUPPLY VOLTAGES,

SUPPLY CURRENT, INTERNAL AND

REMOTE TEMPERATURES

–25

0

50

75 100 125

–50

25

T

(°C)

AMB

2990 TA01b

2990f

ꢀ

LTC2990

absoluTe MaxiMuM raTings

pin conFiguraTion

(Note ±)

TOP VIEW

Supply Voltage V ................................... –0.3V to 6.0V

CC

V1

V2

1

2

3

4

5

10

9

V

CC

Input Voltages V1, V2, V3, V4, SDA, SCL,

ADR1

ADR0

SCL

V3

8

ADR1, ADR2..................................–0.3V to (V + 0.3V)

CC

V4

GND

7

6

Operating Temperature Range

SDA

LTC2990C................................................ 0°C to 70°C

LTC2990I.............................................–40°C to 85°C

Storage Temperature Range .................. –65°C to 150°C

Lead Temperature (Soldering, 10 sec)...................300°C

MS PACKAGE

10-LEAD PLASTIC MSOP

T

= 125°C, θ = 150°C/W

JA

JMAX

orDer inForMaTion

LEꢀD FREE FꢂNꢂSH

LTC2990CMS#PBF

LTC2990IMS#PBF

LEꢀD BꢀSED FꢂNꢂSH

LTC2990CMS

TꢀPE ꢀND REEL

PꢀRT MꢀRKꢂNG*

LTDSQ

PꢀCKꢀGE DESCRꢂPTꢂON

10-Lead Plastic MSOP

PꢀCKꢀGE DESCRꢂPTꢂON

10-Lead Plastic MSOP

TEMPERꢀTURE RꢀNGE

0°C to 70°C

LTC2990CMS#TRPBF

LTC2990IMS#TRPBF

TꢀPE ꢀND REEL

LTDSQ

–40°C to 85°C

PꢀRT MꢀRKꢂNG*

LTDSQ

TEMPERꢀTURE RꢀNGE

0°C to 70°C

LTC2990CMS#TR

LTC2990IMS#TR

LTC2990IMS

LTDSQ

–40°C to 85°C

Consult LTC Marketing for parts speciﬁed with wider operating temperature ranges. *The temperature grade is identiﬁed by a label on the shipping container.

Contact LTC Marketing for parts trimmed to ideality factors other than 1.004.

For more information on lead free part marking, go to: http://www.linear.com/leadfree/

For more information on tape and reel speciﬁcations, go to: http://www.linear.com/tapeandreel/

elecTrical characTerisTics ^Thel denotes the speAiﬁAations whiAh applc over the full operating

temperature range, otherwise speAiﬁAations are at T_ꢀ= ꢁ51C. V_CC= 3.3V, unless otherwise noted.

SYMBOL

General

PꢀRꢀMETER

CONDꢂTꢂONS

MꢂN

TYP

MꢀX

UNꢂTS

l

V

Input Supply Range

Input Supply Current

Input Supply Undervoltage Lockout

2.9

5.5

1.8

5

V

CC

2

I

CC

I

SD

During Conversion, I C Inactive

1.1

1

2.1

mA

µA

V

2

Shutdown Mode, I C Inactive

V

1.3

2.7

CC(UVL)

Measurement ꢀAAuraAc

l

T

Internal Temperature Total Unadjusted

Error

LTC2990C

LTC2990I

1

2.5

5

°C

INT(TUE)

–3

–2

–3

T

= –40°C to 25°C

= 25°C to 85°C

5

AMB

T

AMB

1

l

T

Remote Diode Temperature Total

Unadjusted Error

0.5

1.5

°C

η = 1.004 (Note 4)

RMT(TUE)

l

V

Voltage Total Unadjusted Error

2.9V ≤ V ≤ 5.5V

0V ≤ V ≤ V , V ≤ 4.9V

N CC n

0.1

0.2

0.25

0.75

%

CC(TUE)

CC

V1 Through V4 Total Unadjusted Error

Differential Voltage Total Unadjusted Error –300mV ≤ V ≤ 300mV

V1 – V2 or V3 – V4

n(TUE)

DIFF(TUE)

D

l

V

Maximum Differential Voltage

Differential Voltage Common Mode Range

Differential Voltage LSB Weight

Single-Ended Voltage LSB Weight

Temperature LSB Weight

Temperature Noise

–300

0

300

mV

V

µV

Deg

°RMS

°/√Hz

2990f

DIFF(MAX)

DIFF(CMR)

LSB(DIFF)

V

CC

19.42

305.18

0.0625

0.2

0.05

LSB(SINGLE-ENDED)

LSB(TEMP)

NOISE

Celsius or Kelvin

T

= 46ms (Note 2)

MEAS

ꢁ

LTC2990

elecTrical characTerisTics ^Thel denotes the speAiﬁAations whiAh applc over the full operating

temperature range, otherwise speAiﬁAations are at T_ꢀ= ꢁ51C. V_CC= 3.3V, unless otherwise noted.

SYMBOL

Res

INL

PꢀRꢀMETER

Resolution (No Missing Codes)

Integral Nonlinearity

CONDꢂTꢂONS

(Note 2)

MꢂN

14

TYP

MꢀX

UNꢂTS

Bits

l

2.9V ≤ V ≤ 5.5V, V

= 1.5V

CC

IN(CM)

(Note 2)

Single-Ended

Differential

–2

2

LSB

C

V1 Through V4 Input Sampling

Capacitance

V1 Through V4 Input Average Sampling

Current

(Note 2)

0.35

0.6

pF

µA

nA

IN

I

0V ≤ V ≤ 3V (Note 2)

N

IN(AVG)

DC_LEAK(VIN)

l

V1 Through V4 Input Leakage Current

0V ≤ V ≤ V

–10

10

N

CC

Measurement Delac

, T , T

V1, V2, V3, V4

l

T

Per Conﬁgured Temperature Measurement (Note 2)

37

1.2

46

1.5

55

1.8

167

ms

INT R1 R2

Single-Ended Voltage Measurement

Differential Voltage Measurement

(Note 2) Per Voltage, Two Minimum

V1 – V2, V3 – V4

(Note 2)

V

Measurement

CC

Max Delay

Mode[4:0] = 11101, T , T , T , V

INT R1 R2 CC

V±, V3 Output (Remote Diode Mode Onlc)

l

I

Output Current

Output Voltage

Remote Diode Mode

260

350

V

CC

µA

V

OUT

V

0

OUT

ꢁ

ꢂ C ꢂnterfaAe

l

V

ADR0, ADR1 Input Low Threshold Voltage Falling

ADR0, ADR1 Input High Threshold Voltage Rising

0.3 • V

V

ADR(L)

CC

V

0.7 • V

ADR(H)

CC

V

SDA Low Level Maximum Voltage

Maximum Low Level Input Voltage

Minimum High Level Input Voltage

SDA, SCL Input Current

I = –3mA, V = 2.9V to 5.5V

SDA and SCL Pins

0.4

0.3 • V

OL1

O

CC

IL

IH

CC

I

0 < V

,

< V

CC

1

µA

SDAI,SCLI

SDA SCL

Maximum ADR0, ADR1 Input Current

ADR0 or ADR1 Tied to V or GND

CC

ADR(MAX)

ꢁ

ꢂ C Timing (Note ꢁ)

f

t

Maximum SCL Clock Frequency

Minimum SCL Low Period

Minimum SCL High Period

Minimum Bus Free Time Between Stop/

Start Condition

400

kHz

µs

ns

SCL(MAX)

LOW

1.3

600

1.3

HIGH

µs

BUF(MIN)

t

Minimum Hold Time After (Repeated)

Start Condition

Minimum Repeated Start Condition Set-Up

Time

600

ns

HD,STA(MIN)

SU,STA(MIN)

t

Minimum Stop Condition Set-Up Time

Minimum Data Hold Time Input

Minimum Data Hold Time Output

Minimum Data Set-Up Time Input

Maximum Suppressed Spike Pulse Width

SCL, SDA Input Capacitance

600

0

900

100

250

10

ns

pF

SU,STO(MIN)

HD,DATI(MIN)

HD,DATO(MIN)

SU,DAT(MIN)

SP(MAX)

300

50

C

X

Note ±: Stresses beyond those listed under Absolute Maximum Ratings

may cause permanent damage to the device. Exposure to any Absolute

Maximum Rating condition for extended periods may affect device

reliability and lifetime.

Note 4: Trimmed to an ideality factor of 1.004 at 25°C. Remote diode

temperature drift (TUE) veriﬁed at diode voltages corresponding to

the temperature extremes with the LTC2990 at 25°C. Remote diode

temperature drift (TUE) guaranteed by characterization over the LTC2990

operating temperature range.

Note ꢁ: Guaranteed by design and not subject to test.

Note 3: Integral nonlinearity is deﬁned as the deviation of a code from a

straight line passing through the actual endpoints of the transfer curve.

The deviation is measured from the center of the quantization band.

2990f

ꢂ

LTC2990

Typical perForMance characTerisTics ^T_ꢀ^{= ꢁ51C, V}_CC= 3.3V unless otherwise noted

Measurement Delac Variation

vs T Normalized to 3.3V, ꢁ51C

Supplc Current vs Temperature

Shutdown Current vs Temperature

1200

1150

1100

1050

1000

950

3.5

3.0

4

3

V

= 5V

CC

V

= 5V

CC

2.5

V

= 5V

CC

2

2.0

1.5

1.0

0.5

1

V

= 3.3V

CC

V

= 3.3V

CC

V

= 3.3V

CC

0

–1

–25

0

150

–50

25 50 75 100 125

(°C)

–25

0

150

–50

25 50 75 100 125

(°C)

–25

0

150

–50

25 50 75 100 125

(°C)

T

AMB

2990 G02

2990 G01

2990 G03

V_CCTUE

Single-Ended V_XTUE

Differential Voltage TUE

0.10

0.05

0

1.0

0.5

0.10

0.05

0

V

= 5V

CC

0

V

= 3.3V

CC

–0.05

–0.10

–0.5

–1.0

–0.05

–0.10

–25

0

150

–25

0

150

–50

25 50 75 100 125

(°C)

–50

25 50 75 100 125

(°C)

–25

0

150

25 50 75 100 125

–50

T

AMB

T

(°C)

AMB

2990 G05

2990 G06

2990 G04

Remote Diode Error with LTCꢁ990

at ꢁ51C, 901C

Remote Diode Error with LTCꢁ990

at Same Temperature as Diode

T_ꢂNTERNꢀLError

4

3

1.00

0.75

0.50

0.25

0.6

0.4

LTC2990

AT 25°C

2

0.2

1

0

LTC2990

AT 90°C

–0.25

0

–0.2

–0.4

–0.6

–1

–2

–0.50

–0.75

–1.00

–3

–25

0

150

–25

0

150

–50

25 50 75 100 125

–50

25 50 75 100 125

(°C)

–25

0

150

–50

25 50 75 100 125

T

(°C)

T

AMB

BATH TEMPERATURE (°C)

AMB

2990 G07

2990 G09

2990 G08

2990f

ꢃ

LTC2990

T_ꢀ= ꢁ51C, V_CC= 3.3V unless otherwise noted

Typical perForMance characTerisTics

Single-Ended Noise

Single-Ended Transfer FunAtion

Single-Ended ꢂNL

6

4000

1.0

0.5

0

4800 READINGS

3500

3000

5

4

3

2

1

V

= 5V

CC

V

= 3.3V

CC

V

CC

= 3.3V

2500

2000

1500

1000

500

V

= 5V

CC

–0.5

0

–1.0

–1

0

1

2

3

(V)

4

5

–2

–1

1

2

3

5

6

–3

0

–1 –0

1

2

4

V

X

LSBs (305.18µV/LSB)

V

(V)

X

2990 G12

2990 G10

2990 G11

LTCꢁ990 Differential Noise

Differential Transfer FunAtion

Differential ꢂNL

2

1

500

400

300

200

100

0

0.4

0.3

800 READINGS

0.2

0.1

0

–0.1

–0.2

–0.3

–0.4

–1

–2

0

0.2

–0.4

0.4

0

–0.2

–4 –3 –2 –1

1

2

3

0

0.1

–0.4 –0.3 –0.2 –0.1

0.2 0.3 0.4

V

(V)

LSBs (19.42µV/LSB)

V1-V2 (V)

IN

2990 G15

2990 G13

2990 G14

T_ꢂNTNoise

Remote Diode Noise

POR Thresholds vs Temperature

500

400

300

200

100

0

600

500

400

300

200

100

0

2.6

2.4

2.2

2.0

1.8

1.6

1.4

1.2

1.0

1000 READINGS

V

RISING

CC

V

FALLING

CC

–0.75 –0.5 –0.25

0

(°C)

0.25 0.5 0.75

–0.75 –0.5 –0.25

0

0.25 0.5 0.75

50 75

(°C)

–50 –25

0

25

T

100 125 150

(°C)

AMB

2990 G16

2990 G17

2990 G18

2990f

ꢄ

LTC2990

pin FuncTions

SDꢀ (Pin 6): Serial Bus Data Input and Output. In the

transmitter mode (Read), the conversion result is output

through the SDA pin, while in the receiver mode (Write),

the device conﬁguration bits are input through the SDA

pin. At data input mode, the pin is high impedance; while

at data output mode, it is an open-drain N-channel driver

andthereforeanexternalpull-upresistororcurrentsource

V± (Pin ±): First Monitor Input. This pin can be conﬁg-

ured as a single-ended input or the positive input for a

differential or remote diode temperature measurement (in

combination with V2). When conﬁgured for remote diode

temperature, this pin will source a current.

Vꢁ (Pin ꢁ): Second Monitor Input. This pin can be con-

ﬁgured as a single-ended input or the negative input for a

differential or remote diode temperature measurement (in

combination with V1). When conﬁgured for remote diode

temperature, this pin will have an internal termination,

while the measurement is active.

to V is needed.

CC

SCL (Pin 7): Serial Bus Clock Input. The LTC2990 can

only act as a slave and the SCL pin only accepts external

serial clock. The LTC2990 does not implement clock

stretching.

V3 (Pin 3): Third Monitor Input. This pin can be conﬁg-

ured as a single-ended input or the positive input for a

differential or remote diode temperature measurement (in

combination with V4). When conﬁgured for remote diode

temperature, this pin will source a current.

ꢀDR0(Pin8):SerialBusAddressControlInput.TheADR0

2

pin is an address control bit for the device I C address.

ꢀDR± (Pin 9): Serial Bus Address Control Input. The

2

ADR1 pin is an address control bit for the device I C

V4 (Pin 4): Fourth Monitor Input. This pin can be conﬁg-

ured as a single-ended input or the negative input for a

differential or remote diode temperature measurement (in

combination with V3). When conﬁgured for remote diode

temperature, this pin will have an internal termination,

while the measurement is active.

address. See Table 1.

V

(Pin ±0): Supply Voltage Input.

CC

GND (Pin 5): Device Circuit Ground. Connect this pin to a

ground plane through a low impedance connection.

2990f

ꢅ

LTC2990

FuncTional DiagraM

REMOTE

DIODE

SENSORS

V

10

5

CC

MODE

V1

GND

1

V2

SCL

SDA

2

CONTROL

LOGIC

7

6

8

9

V3

3

MUX

2

ADC

ADR0

ADR1

I C

V4

4

UV

INTERNAL

SENSOR

V

CC

UNDERVOLTAGE

DETECTOR

REFERENCE

2990 FD

TiMing DiagraM

SDAI/SDAO

t

SP

t

SU, DAT

t

SU,STA

BUF

HD,DATO,

HD,DATI

t

HD,STA

t

SU,STO

t

SP

2990 TD

SCL

t

HD,STA

START

CONDITION

REPEATED START

CONDITION

STOP

CONDITION

START

CONDITION

2990f

ꢆ

LTC2990

operaTion

The LTC2990 monitors voltage, current, internal and

threshold. During an undervoltage condition, the part is in

a reset state, and the data and control registers are placed

in the default state of 00h.

remote temperatures. It can be conﬁgured through an

2

I C interface to measure many combinations of these pa-

rameters. Single or repeated measurements are possible.

Remote temperature measurements use a transistor as

a temperature sensor, allowing the remote sensor to be a

discreteNPN(ex.MMBT3904)oranembeddedPNPdevice

in a microprocessor or FPGA. The internal ADC reference

minimizes the number of support components required.

Remotediodemeasurementsareconductedusingmultiple

ADC conversions and source currents to compensate for

sensor series resistance. During temperature measure-

ments, the V2 or V4 terminal of the LTC2990 is terminated

with a diode. The LTC2990 is calibrated to yield the correct

temperature for a remote diode with an ideality factor of

1.004. See the applications section for compensation of

sensor ideality factors other than the factory calibrated

value of 1.004.

The Functional Diagram displays the main components of

the device. The input signals are selected with an input

MUX, controlled by the control logic block. The control

logic uses the mode bits in the control register to manage

the sequence and types of data acquisition. The control

logic also controls the variable current sources during

remote temperature acquisition. The order of acquisitions

2

TheLTC2990communicatesthroughanI Cserialinterface.

The serial interface provides access to control, status and

2

data registers. I C deﬁnes a 2-wire open-drain interface

supporting multiple slave devices and masters on a single

bus. The LTC2990 supports 100kbits/s in the standard

mode and up to 400kbit/s in fast mode. The four physical

is ﬁxed: T

, V1, V2, V3, V4 then V . The ADC

INTERNAL

CC

performs the necessary conversion(s) and supplies the

data to the control logic for further processing in the case

of temperature measurements, or routing to the appropri-

ate data register for voltage and current measurements.

Current and temperature measurements, V1 – V2 or V3

– V4, are sampled differentially by the internal ADC. The

2

addressessupportedarelistedinTable1.TheI Cinterface

is used to trigger single conversions, or start repeated

conversions by writing to a dedicated trigger register. The

data registers contain a destructive-read status bit (data

valid), which is used in repeated mode to determine if

the register’s contents have been previously read. This

bit is set when the register is updated with new data, and

cleared when read.

2

I C interface supplies access to control, status and data

registers. The ADR1 and ADR0 pins select one of four

2

possible I C addresses (see Table 1). The undervoltage

2

detector inhibits I C communication below the speciﬁed

applicaTions inForMaTion

Figure 1 is the basic LTC2990 application circuit.

Power Up

R

SENSE

The V pin must exceed the undervoltage (UV) thresh-

CC

15mΩ

2.5V

5V

old of 2.5V to keep the LTC2990 out of power-on reset.

Power-on reset will clear all of the data registers and the

control register.

I

LOAD

0.1µF

2-WIRE

MMBT3904

V

V1

V2

V3

CC

SDA

SCL

ADR0

ADR1

2

I C

INTERFACE

LTC2990

GND

470pF

Temperature Measurements

V4

2990 F01

The LTC2990 can measure internal temperature and up

to two external diode or transistor sensors. During tem-

perature conversion, current is sourced through either

the V1 or the V3 pin to forward bias the sensing diode.

Figure ±

2990f

ꢇ

LTC2990

applicaTions inForMaTion

sensor can be considered a temperature scaling factor.

The temperature error for a 1% accurate ideality factor

error is 1% of the Kelvin temperature. Thus, at 25°C, or

298°K, a +1% accurate ideality factor error yields a +2.98

degree error. At 85°C or 358°K, a +1% error yields a 3.6

degree error. It is possible to scale the measured Kelvin

or Celsius temperature measured using the LTC2990 with

a sensor ideality factor other than 1.004, to the correct

value. The scaling Equations (3) and (4) are simple, and

can be implemented with sufﬁcient precision using 16-bit

ﬁxed-point math in a microprocessor or microcontroller.

The change in sensor voltage per degree temperature

change is 275µV/°C, so environmental noise must be kept

to a minimum. Recommended shielding and PCB trace

considerations are illustrated in Figure 2.

The diode equation:

 

I_C

k • T

q

V_BE= η•

•ln

(1)

 

I

 

S

can be solved for T, where T is Kelvin degrees, I is a

S

process dependent factor on the order of 1E-13, η is the

diode ideality factor, k is Boltzmann’s constant and q is

the electron charge.

Factory Ideality Calibration Value:

η

CAL

= 1.004

V_BE•q

Actual Sensor Ideality Value:

T =

(2)

 

I_C

η•k •In

η

ACT

 

I

 

S

Compensated Kelvin Temperature:

The LTC2990 makes differential measurements of diode

voltage to calculate temperature. Proprietary techniques

allow for cancellation of error due to series resistance.

η_ACT

η_CAL

(3)

(4)

T_{K_COMP}

=

• T

K_MEAS

Compensated Celsius Temperature

0.1µF









η_ACT

η_CAL

GND SHIELD

LTC2990

T_{C_COMP}

=

• T

(

+ 273 – 273

TRACE

)



C_MEAS

V1

V2

V3

V4

V

CC

ADR1

ADR0

SCL



470pF

A 16-bit unsigned number is capable of representing the

GND SDA

ratio η /η

in a range of 0.00003 to 1.99997, by

ACT CAL

NPN SENSOR

2990 F02

15

multiplying the fractional ratio by 2 . The range of scal-

ing encompasses every conceivable target sensor value.

The ideality factor scaling granularity yields a worst-case

temperatureerrorof0.01°at125°C.Multiplyingthis16-bit

unsigned number and the measured Kelvin (unsigned)

temperature represented as a 16-bit number, yields a

32-bit unsigned result. To scale this number back to a

13-bittemperature(9-bitintegerpart,anda4-bitfractional

Figure ꢁ. ReAommended PCB Lacout

ꢂdealitc FaAtor SAaling

The LTC2990 is factory calibrated for an ideality factor of

1.004, which is typical of the popular MMBT3904 NPN

transistor. The semiconductor purity and wafer-level pro-

cessing limits device-to-device variation, making these

devicesinterchangeable(typically<0.5C)fornoadditional

cost. Several manufacturers supply suitable transistors,

some recommended sources are listed in Table 10. While

an ideality factor value of 1.004 is typical of target sen-

sors, small deviations can yield signiﬁcant temperature

errors. ContactLTCMarketingforpartstrimmedtoideality

factors other than 1.004. The ideality factor of the diode

15

part), dividethenumberby2 perEquation(5). Similarly,

Celsius coded temperature values can be scaled using

16-bit ﬁxed-point arithmetic, using Equation (6). In both

cases, the scaled result will have a 9-bit integer (d[12:4])

and the 4LSBs (d[3:0]) representing the 4-bit fractional

part. To convert the corrected result to decimal, divide

4

the ﬁnal result by 2 or 16, as you would the register

contents. If ideality factor scaling is implemented in the

2990f

ꢈ

LTC2990

applicaTions inForMaTion

target application, it is beneﬁcial to conﬁgure the LTC2990

forKelvincodedresultstolimitthenumberofmathopera-

tions required in the target processor.

The maximum source impedance to yield 14-bit results

with, 1/2LSB full-scale error is ~50Ω. In order to achieve

highaccuracy,4-point,orKelvinconnectedmeasurements

of the sense resistor differential voltage are necessary.



₁₅

η

2¹⁵

Unsigned

^ACT2 T_{K_MEAS}

(

)





In the case of current measurements, the external sense

resistor is typically small, and determined by the full-scale

input voltage of the LTC2990. The full-scale differential

voltage is 0.300V. The external sense resistance is then a





CAL

(5)

(6)

T_{K_COMP}

=



₁₅

η

Unsigned

^ACT2

CAL

T

_{C_MEAS}+273.15•2⁴

(

)

(

)









2¹⁵

functionofthemaximummeasurablecurrent,orR

EXT_MAX

T_{C_COMP}

= 0.300/I

. For example, if you wanted to measure a

MAX

– 273.15•2⁴

current range of 5A, the external shunt resistance would

equal 0.300/5 = 60mΩ.

Sampling Currents

Thereexistsawaytoimprovethesenseresistor’sprecision

usingtheLTC2990.TheLTC2990measuresbothdifferential

voltage and remote temperature. It is therefore, possible

to compensate for the absolute resistance tolerance of the

senseresistorandthetemperaturecoefﬁcientofthesense

resistor in software. The resistance would be measured

by running a calibrated test current through the discrete

resistor. The LTC2990 would measure both the differential

voltage across this resistor and the resistor temperature.

Single-ended voltage measurements are directly sampled

by the internal ADC. The average ADC input current is a

function of the input applied voltage as follows:

I

= (V – 1.49) • 0.17µA

IN

IN(AVG)

Inputs with source resistance less than 200Ω will yield

full-scalegainerrorsduetosourceimpedanceof<1/2LSB

for 14-bit conversions. The nominal conversion time is

1.5ms for single-ended conversions.

From this measurement, R and T in the equation be-

O

low would be known. Using the two equations, the host

microprocessor could compensate for both the absolute

tolerance and the TCR.

Current Measurements

The LTC2990 has the ability to perform 14-bit current

measurements with the addition of a current sense resis-

tor (see Figure 3).

R = R • [1 + α(T – T )]

T

O

where:

In order to achieve accurate current sensing a few de-

tails must be considered. Differential voltage or current

measurementsaredirectlysampledbytheinternalADC.The

average ADC input current for each leg of the differential

ꢀ α = +3930 ppm/°C for copper trace

ꢀ α = 2 to ~+200ppm/°C for discrete R

(7)

(8)

I = (V1 – V2)/R

input signal during a conversion is (V – 1.49) • 0.34µA.

T

IN

R

SENSE

0V – V

CC

I

LOAD

V1

V2

LTC2990

2990 F03

Figure 3. Simpliﬁed Current Sense SAhematiA

2990f

ꢀ0

LTC2990

applicaTions inForMaTion

DeviAe Conﬁguration

accessed. Bit 6 of the register is a sensor-shorted alarm.

This bit of the corresponding register will be high if the

The LTC2990 is conﬁgured by writing the control register

through the serial interface. Refer to Table 4 for control

register bit deﬁnition. The device is capable of many ap-

plication conﬁgurations including voltage, temperature

and current measurements. It is possible to conﬁgure the

device for single or repeated acquisitions. For repeated

acquisitions,onlytheinitialtriggerisrequiredandnewdata

is written over the old data. Acquisitions are frozen during

serial read data transfers to prevent the upper and lower

data bytes for a particular measurement from becoming

out of sync. Internally, both the upper and lower bytes

are written at the same instant. Since serial data transfer

timeout is not implemented, failure to terminate a read

operation will yield an indeﬁnitely frozen wait state. The

device can also make single measurements, or with one

trigger,allofthemeasurementsfortheconﬁguration.When

the device is conﬁgured for multiple measurements, the

order of measurements is ﬁxed. As each new data result

is ready, the MSB of the corresponding data register is

set, and the corresponding status register bit is set. These

bits are cleared when the corresponding data register is

addressed. The conﬁguration register value at power-up

yields the measurement of only the internal temperature

sensor, if triggered. The four input pins V1 through V4 will

be in a high impedance state, until conﬁgured otherwise,

and a measurement triggered.

remotesensordiodedifferentialvoltageisbelow0.14V .

DC

The LTC2990 internal bias circuitry maintains this voltage

above this level during normal operating conditions. Bit 5

of the register is a sensor open alarm. This bit of the cor-

respondingregisterwillbehighiftheremotesensordiode

differential voltage is above 1.0V . The LTC2990 internal

DC

biascircuitrymaintainsthisvoltagebelowthislevelduring

normal operating conditions. The two sensor alarms are

only valid after a completed conversion indicated by the

data_valid bit being high. Bit 4 through Bit 0 of the MSB

register are the conversion result bits D[12:8], in two’s

compliment format. Note in Kelvin results, the result will

alwaysbepositive. TheLSBregistercontainstemperature

result bits D[7:0]. To convert the register contents to

temperature, use the following equation:

T = D[12:0]/16.

See Table 9 for conversion value examples.

Voltage/Current:Voltageresultsarereportedintworespec-

tive registers, an MSB and LSB register. The Voltage MSB

result register most signiﬁcant bit (Bit 7) is the data_valid

bit, which indicates whether the current register contents

have been accessed since the result was written to the

register. This bit will be set when the register contents are

new, and cleared when accessed. Bit 6 of the MSB register

is the sign bit, Bits 5 though 0 represent bits D[13:8] of

the two’s complement conversion result. The LSB register

holds conversion bits D[7:0]. The LSB value is different

for single-ended voltage measurements V1 through V4,

and differential (current measurements) V1 – V2 and V3

– V4. Single-ended voltages are limited to positive values

intherange0Vto3.5V. Differentialvoltagescanhaveinput

values in the range of –0.300V to 0.300V.

Data Format

The data registers are broken into 8-bit upper and lower

bytes. Voltage and current conversions are 14-bits. The

upper bits in the MSB registers provide status on the

resulting conversions. These status bits are different for

temperature and voltage conversions:

Temperature: Temperature conversions are reported as

Celsius or Kelvin results described in Tables 7 and 8,

each with 0.0625 degree-weighted LSBs. The format is

controlled by the control register, Bit 7. All temperature

Use the following equations to convert the register values

(see Table 9 for examples):

V

= D[13:0] • 305.18µV

SINGLE-ENDED

DIFFERENTIAL

formats, T , T and T are controlled by this bit. The

INT R1

R2

= D[13:0] • 19.42µV, if Sign = 0

= (D[13:0] +1) • –19.42µV, if Sign = 1

Temperature MSB result register most signiﬁcant bit

(Bit 7) is the DATA_VALID bit, which indicates whether

the current register contents have been accessed since

the result was written to the register. This bit will be set

when new data is written to the register, and cleared when

Current = D[13:0] • 19.42µV/R , if Sign = 0

SENSE

Current=(D[13:0]+1)•–19.42µV/R

,ifSign=1,

SENSE

2990f

ꢀꢀ

LTC2990

applicaTions inForMaTion

where R

<1Ω.

is the current sensing resistor, typically

STꢀRT and STOP Conditions

SENSE

When the bus is idle, both SCL and SDA must be high. A

bus master signals the beginning of a transmission with

a START condition by transitioning SDA from high to low

while SCL is high. When the bus is in use, it stays busy

if a repeated START (SR) is generated instead of a STOP

condition. The repeated START (SR) conditions are func-

tionally identical to the START (S). When the master has

ﬁnished communicating with the slave, it issues a STOP

condition by transitioning SDA from low to high while SCL

is high. The bus is then free for another transmission.

V :TheLTC2990measuresV .Toconvertthecontentsof

CC

the V register to voltage, use the following equation:

CC

V

= 2.5 + D[13:0] • 305.18µV

CC

Digital ꢂnterfaAe

The LTC2990 communicates with a bus master using a

2

two-wire interface compatible with the I C Bus and the

2

SMBus, an I C extension for low power devices.

The LTC2990 is a read-write slave device and supports

SMBusbusReadByteDataandWriteByteData,ReadWord

Data and Write Word Data commands. The data formats

for these commands are shown in Tables 2 though 9.

ꢁ

ꢂ C DeviAe ꢀddressing

Four distinct bus addresses are conﬁgurable using the

ADR0-ADR1 pins. Table 1 shows the correspondence

between ADR0 and ADR1 pin states and addresses.

The connected devices can only pull the bus wires LOW

and can never drive the bus HIGH. The bus wires are

externally connected to a positive supply voltage via a

current source or pull-up resistor. When the bus is free,

ꢀAknowledge

The acknowledge signal is used for handshaking between

thetransmitterandthereceivertoindicatethatthelastbyte

of data was received. The transmitter always releases the

SDA line during the acknowledge clock pulse. When the

slave is the receiver, it must pull down the SDA line so that

it remains LOW during this pulse to acknowledge receipt

of the data. If the slave fails to acknowledge by leaving

SDA HIGH, then the master can abort the transmission by

generatingaSTOPcondition.Whenthemasterisreceiving

data from the slave, the master must pull down the SDA

line during the clock pulse to indicate receipt of the data.

After the last byte has been received the master will leave

the SDA line HIGH (not acknowledge) and issue a STOP

condition to terminate the transmission.

2

bothlinesareHIGH. DataontheI Cbuscanbetransferred

at rates of up to 100kbit/s in the standard mode and up to

2

400kbit/s in the fast mode. Each device on the I C bus is

recognized by a unique address stored in that device and

can operate as either a transmitter or receiver, depending

on the function of the device. In addition to transmitters

and receivers, devices can also be considered as masters

or slaves when performing data transfers. A master is

the device which initiates a data transfer on the bus and

generates the clock signals to permit that transfer. At the

same time any device addressed is considered a slave.

The LTC2990 can only be addressed as a slave. Once ad-

dressed, it can receive conﬁguration bits or transmit the

last conversion result. Therefore the serial clock line SCL

is an input only and the data line SDA is bidirectional. The

device supports the standard mode and the fast mode for

data transfer speeds up to 400kbit/s. The Timing Diagram

shows the deﬁnition of timing for fast/standard mode

Write ProtoAol

The master begins communication with a START condi-

tion followed by the seven bit slave address and the R/W#

bit set to zero. The addressed LTC2990 acknowledges

the address and then the master sends a command byte

which indicates which internal register the master wishes

to write. The LTC2990 acknowledges the command byte

and then latches the lower four bits of the command byte

into its internal Register Address pointer. The master then

2

devices on the I C bus. The internal state machine cannot

2

updateinternaldataregistersduringanI Creadoperation.

2

The state machine pauses until the I C read is complete.

It is therefore, important not to leave the LTC2990 in this

state for long durations, or increased conversion latency

will be experienced.

2990f

ꢀꢁ

LTC2990

applicaTions inForMaTion

delivers the data byte and the LTC2990 acknowledges

once more and latches the data into its internal register.

The transmission is ended when the master sends a STOP

condition. If the master continues sending a second data

byte, as in a Write Word command, the second data byte

willbeacknowledgedbytheLTC2990andwrittentothenext

register in sequence, if this register has write access.

Control Register

The control register (Table 3) determines the selected

measurement mode of the device. The LTC2990 can be

conﬁgured to measure voltages, currents and tempera-

tures.Thesemeasurementscanbesingle-shotorrepeated

measurements. Temperatures can be set to report in

Celsius or Kelvin temperature scales. The LTC2990 can be

conﬁguredtorunparticularmeasurements, orallpossible

measurementspertheconﬁgurationspeciﬁedbythemode

bits. The power-on default conﬁguration of the control

register is set to 0x00, which translates to a repeated

measurement of the internal temperature sensor, when

triggered. This mode prevents the application of remote

diode test currents on pins V1 and V3, and remote diode

terminations on pins V2 and V4 at power-up.

Read ProtoAol

ThemasterbeginsareadoperationwithaSTARTcondition

followed by the seven bit slave address and the R/W# bit

settozero.TheaddressedLTC2990acknowledgesthisand

then the master sends a command byte which indicates

which internal register the master wishes to read. The

LTC2990acknowledgesthisandthenlatchesthelowerfour

bitsofthecommandbyteintoitsinternalRegisterAddress

pointer.ThemasterthensendsarepeatedSTARTcondition

followed by the same seven bit address with the R/W# bit

now set to one. The LTC2990 acknowledges and sends

the contents of the requested register. The transmission

is ended when the master sends a STOP condition. The

register pointer is automatically incremented after each

byte is read. If the master acknowledges the transmitted

data byte, as in a Read Word command, the LTC2990

will send the contents of the next sequential register as

the second data byte. The byte following register 0x0F is

register 0x00, or the status register.

Status Register

The status register (Table 3) reports the status of a par-

ticular conversion result. When new data is written into a

particular result register, the corresponding DATA_VALID

bit is set. When the register is addressed by the I

face, the status bit (as well as the DATA_VALID bit in the

respectiveregister)iscleared.Thehostcanthendetermine

if the current available register data is new or stale. The

busy bit, when high, indicates a single-shot conversion is

in progress. The busy bit is always high during repeated

mode, after the initial conversion is triggered.

2

C inter-

a6-a0

b7-b0

1-7

8

9

1-7

8

9

1-7

8

9

P

S

START

ADDRESS

R/W

ACK

DATA

ACK

DATA

ACK

STOP

2990 F04

Figure 4. Data Transfer Over ꢂ^ꢁC or SMBus

S

ADDRESS W#

10011a1:a0

A

0

COMMAND

A

0

DATA

b7:b0

A

0

P

0

XXXXXb3:b0

FROM MASTER TO SLAVE

FROM SLAVE TO MASTER

A: ACKNOWLEDGE (LOW)

A#: NOT ACKNOWLEDGE (HIGH)

R: READ BIT (HIGH)

W#: WRITE BIT (LOW)

S: START CONDITION

P: STOP CONDITION

2990 F05

Figure 5. LTCꢁ990 Serial Bus Write Bcte ProtoAol

2990f

ꢀꢂ

LTC2990

applicaTions inForMaTion

S

ADDRESS W#

A

0

COMMAND

A

0

DATA

b7:b0

A

0

DATA

b7:b0

A

0

P

10011a1:a0

0

XXXXXb3:b0

2990 F06

Figure 6. LTCꢁ990 Serial Bus Repeated Write Bcte ProtoAol

S

ADDRESS W#

10011a1:a0

A

0

COMMAND

A

0

S

ADDRESS

R

1

A

0

DATA A#

b7:b0

P

0

XXXXXb3:b0

10011a1:a0

1

2990 F07

Figure 7. LTCꢁ990 Serial Bus Read Bcte ProtoAol

S

ADDRESS W#

10011a1:a0

A

0

COMMAND

A

0

S

ADDRESS

R

1

A

0

DATA

b7:b0

A

0

DATA A#

b7:b0

P

0

XXXXXb3:b0

10011a1:a0

1

2990 F08

Figure 8. LTCꢁ990 Serial Bus Repeated Read Bcte ProtoAol

Table ±. ꢂ^ꢁC Base ꢀddress

ꢁ

HEX ꢂ C BꢀSE ꢀDDRESS

BꢂNꢀRY ꢂ C BꢀSE ꢀDDRESS

ꢀDR±

ꢀDR0

98h

1001 100X*

1001 101X*

1001 110X*

1001 111X*

0

1

0

1

0

1

9Ah

9Ch

9Eh

*X = R/W Bit

Table ꢁ. LTCꢁ990 Register ꢀddress and Contents

†

REGꢂSTER ꢀDDRESS*

REGꢂSTER NꢀME

STATUS

REꢀD/WRꢂTE

DESCRꢂPTꢂON

00h

01h

02h

03h

04h

05h

06h

07h

08h

09h

0Ah

0Bh

0Ch

0Dh

0Eh

0Fh

R

Indicates BUSY State, Conversion Status

Controls Mode, Single/Repeat, Celsius/Kelvin

Triggers an Conversion

CONTROL

TRIGGER**

N/A

R/W

Unused Address

T

(MSB)

(LSB)

R

Internal Temperature MSB

Internal Temperature LSB

V1, V1 – V2 or TR1 MSB

V1, V1 – V2 or TR1 LSB

INT

T

INT

V1 (MSB)

V1 (LSB)

V2 (MSB)

V2 (LSB)

V3 (MSB)

V3 (LSB)

V4 (MSB)

V4 (LSB)

V2, V1 – V2 or TR1 MSB

V2, V1 – V2 or TR1 LSB

V3, V3 – V4 or TR2 MSB

V3, V3 – V4 or TR2 LSB

V4, V3 – V4 or TR2 MSB

V4, V3 – V4 or TR2 LSB

V

(MSB)

(LSB)

V

CC

V

CC

MSB

LSB

CC

V

CC

*Register Address MSBs b7-b4 are ignored.

**Writing any value triggers a conversion. Data Returned reading this register address is the Status register.

†

Power-on reset sets all registers to 00h.

2990f

ꢀꢃ

LTC2990

applicaTions inForMaTion

Table 3. STꢀTUS Register

BꢂT

b7

b6

b5

b4

b3

b2

b1

b0

NꢀME

OPERꢀTꢂON

0

Always Zero

V

CC

Ready

1 = V Register Contains New Data, 0 = V Register Read

CC CC

V4 Ready

1 = V4 Register Contains New Data, 0 = V4 Register Read

1 = V3 Register Contains New Data, 0 = V3 Register Data Old

1 = V2 Register Contains New Data, 0 = V2 Register Data Old

1 = V1 Register Contains New Data, 0 = V1 Register Data Old

V3, T2, V3 – V4 Ready

V2 Ready

V1, T1, V1 – V2 Ready

T

INT

Ready

1 = T Register Contains New Data, 0 = T Register Data Old

INT INT

Busy*

1= Conversion In Process, 0 = Acquisition Cycle Complete

*In Repeat mode, Busy = 1 always

Table 4. CONTROL Register

BꢂT

b7

NꢀME

OPERꢀTꢂON

Temperature Format

Temperature Reported In; Celsius = 0, Kelvin = 1

Repeated Acquisition = 0, Single Acquisition = 1

Reserved

b6

Repeat/Single

b5

Reserved

b[4:3]

Mode [4:3]

Mode Description

0

1

0

1

Internal Temperature Only (Reset Value)

T1, V1 or V1 – V2 Only per Mode [2:0]

T2, V3 or V3 – V4 Only per Mode [2:0]

All Measurements per Mode [2:0]

Mode Description

0

1

b[2:0]

Mode [2:0]

0

1

0

1

0

1

0

1

0

1

0

1

0

1

V1, V2, T (Reset Value)

R2

V1 – V2, TR2

V1 – V2, V3, V4

TR1, V3, V4

TR1, V3 – V4

TR1. TR2

V1 – V2, V3 – V4

V1, V2, V3, V4

2990f

ꢀꢄ

LTC2990

applicaTions inForMaTion

Table 5. Voltage/Current Measurement MSB Data Register

Format

BꢂT 7

BꢂT 6

BꢂT 5

BꢂT 4

BꢂT 3

BꢂT ꢁ

BꢂT ±

BꢂT 0

DV*

Sign

D13

D12

D11

D10

D9

D8

*Data Valid is set when a new result is written into the register. Data Valid

2

is cleared when this register is addressed (read) by the I C inteface.

Table 6. Voltage/Current Measurement LSB Data Register

Format

BꢂT 7

BꢂT 6

BꢂT 5

BꢂT 4

BꢂT 3

BꢂT ꢁ

BꢂT ±

BꢂT 0

D7

D6

D5

D4

D3

D2

D1

D0

Table 7. Temperature Measurement MSB Data Register Format

BꢂT 7

BꢂT 6

BꢂT 5

BꢂT 4

BꢂT 3

BꢂT ꢁ

BꢂT ±

BꢂT 0

†

DV*

SS**

SO

D12

D11

D10

D9

D8

*DATA_VALID is set when a new result is written into the register.

2

DATA_VALID is cleared when this register is addressed (read) by the I C

interface.

**Sensor Short is high if the voltage measured on V1 is too low

during temperature measurements. This signal is always low for T

measurements.

INT

†

Sensor Open is high if the voltage measured on V1 is excessive

during temperature measurements. This signal is always low for T

measurements.

Table 8. Temperature Measurement LSB Data Register Format

BꢂT 7

BꢂT 6

BꢂT 5

BꢂT 4

BꢂT 3

BꢂT ꢁ

BꢂT ±

BꢂT 0

D7

D6

D5

D4

D3

D2

D1

D0

2990f

ꢀꢅ

LTC2990

applicaTions inForMaTion

Table 9. Conversion Formats

VOLTꢀGE FORMꢀTS

Single-Ended

SꢂGN

0

BꢂNꢀRY VꢀLUE D[±3:0]

11111111111111

10110011001101

01111111111111

00000000000000

11110000101001

11111111111111

10110011001101

10000000000000

00000000000000

10000000000000

00001110101000

10000000000000

10110011001101

10000000000000

00001010001111

VOLTꢀGE

>5

LSB = 305.18µV

0

3.500

0

2.500

0

0.000

1

–0.300

>0.318

+0.300

+0.159

0.000

Differential

0

LSB = 19.42µV

0

1

–0.159

–0.300

<–0.318

1

V

CC

= Result + 2.5V

0

V

CC

V

CC

= 6V

= 5V

LSB = 305.18µV

0

V

CC

= 2.7V

TEMPERꢀTURE FORMꢀTS

FORMꢀT

Celsius

Kelvin

BꢂNꢀRY VꢀLUE D[±ꢁ:0]

0011111010000

0000110010001

0000110010000

1110110000000

1100011100010

1000100010010

0111010010010

TEMPERꢀTURE

+125.0000

+25.0625

+25.0000

–40.0000

398.1250

273.1250

233.1250

Temperature Internal, T or T

R1

R2

LSB = 0.0625 Degrees

Kelvin

Table ±0. ReAommended Transistors to Be Used as Temperature

Sensors

MꢀNUFꢀCTURER

Fairchild Semiconductor

Central Semiconductor

Diodes, Inc.

PꢀRT NUMBER

MMBT3904

CMPT3904

PꢀCKꢀGE

SOT-23

SC-70

MMBT3904

MMBT3904LT1

MMBT3904

UMT3904

On Semiconductor

NXP

Inﬁneon

Rohm

2990f

ꢀꢆ

LTC2990

Typical applicaTions

Computer Voltage and Temperature Monitoring

High Voltage/Current and Temperature Monitoring

R

1mΩ

1ꢀ

12V

5V

SENSE

V

IN

3.3V

5V TO 105V

10.0k

1%

30.1k

1%

I

R

±0Ω

1ꢀ

LOAD

IN

0A TO 10A

0.1µF

10.0k

1%

10.0k

1%

0.1µF

+IN

–INS

–

+

–INF

V

–

+

MICROPROCESSOR

V

V1

V2

V3

CC

2-WIRE

V

REG

SDA

SCL

ADR0

ADR1

2

I C

LTC2990

GND

470pF

INTERFACE

V4

OUT

LTC610±HV

0.1µF

2990 TA03

R

4.99k

1ꢀ

OUT

±00k

1ꢀ

0.1µF

VOLTAGE, CURRENT AND TEMPERATURE CONFIGURATION:

CONTROL REGISTER: 0x58

T

REG 4, 5

REG 6, 7

REG 8, 9

REG A, B

REG E, F

0.0625°C/LSB

0.61mVLSB

4.75k

1ꢀ

AMB

V1 (+5)

V2(+12)

1.22mV/LSB

T

0.0625°C/LSB

2.5V + 305.18µV/LSB

PROCESSOR

V

CC

5V

0.1µF

MMBT3904

V

V1

V±

V3

CC

±-WIRE

SDA

SCL

ADR0

ADR1

±

I C

LTC±990

GND

470pF

INTERFACE

V4

±990 TA0±

ALL CAPACITORS ±±0ꢀ

VOLTAGE, CURRENT AND TEMPERATURE CONFIGURATION:

CONTROL REGISTER: 0x58

T

REG 4, 5

REG 6, 7

REG 8, 9

REG A, B

REG E, F

0.06±5°C/LSB

13.±mVLSB

1.±±3mA/LSB

0.06±5°C/LSB

±.5V + 305.18µV/LSB

AMB

V

LOAD

V±(I

)

LOAD

T

REMOTE

V

CC

2990f

ꢀꢇ

LTC2990

Typical applicaTions

Motor ProteAtion/Regulation

LOAD

= I • V

0.1Ω

1%

PWR

MOTOR CONTROL VOLTAGE

0V TO 5V

DC

0A TO 2.2A

5V

0.1µF

V

V1

V2

V3

CC

MMBT3904

MOTOR

2-WIRE

SDA

SCL

ADR0

ADR1

2

I C

LTC2990

GND

INTERFACE

470pF

MOTOR

V4

T

2990 TA04

T

INTERNAL

CURRENT AND TEMPERATURE CONFIGURATION:

VOLTAGE AND TEMPERATURE CONFIGURATION:

CONTROL REGISTER: 0x59

CONTROL REGISTER: 0x58

T

REG 4, 5

REG 6, 7

REG A, B

REG E, F

0.0625°C/LSB

194µA/LSB

T

AMB

REG 4, 5

REG 8, 9

REG A, B

REG E, F

0.0625°C/LSB

305.18µVLSB

AMB

I

V

MOTOR

CC

MOTOR

T

0.0625°C/LSB

2.5V + 305.18µV/LSB

T

0.0625°C/LSB

2.5V + 305.18µV/LSB

V

CC

Large Motor ProteAtion/Regulation

LOAD

= I • V

PWR

0.1Ω

1W, 1%

MOTOR CONTROL VOLTAGE

0V TO 40V

0A TO 10A

71.5k

1%

71.5k

1%

10.2k

1%

10.2k

1%

5V

0.1µF

V

V1 V2

CC

MMBT3904

MOTOR

2-WIRE

SDA

SCL

ADR0

ADR1

V3

2

I C

LTC2990

INTERFACE

470pF

MOTOR

V4

GND

T

2990 TA05

T

INTERNAL

VOLTAGE AND TEMPERATURE CONFIGURATION:

CURRENT AND TEMPERATURE CONFIGURATION:

CONTROL REGISTER: 0x58

CONTROL REGISTER: 0x59

T

REG 4, 5

REG 8, 9

REG A, B

REG E, F

0.0625°C/LSB

2.44mVLSB

T

AMB

REG 4, 5

REG 6, 7

REG A, B

REG E, F

0.0625°C/LSB

1.56mA/LSB

AMB

V

I

MOTOR

CC

T

0.0625°C/LSB

2.5V + 305.18µV/LSB

T

0.0625°C/LSB

2.5V + 305.18µV/LSB

V

CC

2990f

ꢀꢈ

LTC2990

Typical applicaTions

Fan/ꢀir Filter/Temperature ꢀlarm

3.3V

MMBT3904

FAN

22Ω

0.125W

470pF

3.3V

0.1µF

HEATER ENABLE

V

MMBT3904

FAN

V1

V2

V3

CC

TEMPERATURE FOR:

GOOD FAN

2-WIRE

SDA

SCL

ADR0

ADR1

2

I C

LTC2990

22Ω

0.125W

INTERFACE

470pF

BAD FAN

V4

GND

HEATER

T

INTERNAL

NDS351AN

HEATER ENABLE

2 SECOND PULSE

2990 TA06

CONTROL REGISTER: 0x5D

T

REG 4, 5

REG 6, 7

REG A, B

REG E, F

0.0625°C/LSB

AMB

R1

R2

0.0625°C/LSB

2.5V + 305.18µV/LSB

V

CC

Batterc Monitoring

BATTERY I AND V MONITOR

15mΩ*

CHARGING

CURRENT

5V

0.1µF

V

V1

V2

V3

CC

MMBT3904

2-WIRE

SDA

SCL

ADR0

ADR1

2

V(t)

T(t)

I(t)

+

I C

LTC2990

NiMH

BATTERY

INTERFACE

470pF

• • •

100%

V4

GND

T

BATT

2990 TA07

T

*IRC LRF3W01R015F

INTERNAL

VOLTAGE AND TEMPERATURE CONFIGURATION:

CURRENT AND TEMPERATURE CONFIGURATION:

CONTROL REGISTER: 0x58

CONTROL REGISTER: 0x59

T

AMB

REG 4, 5

REG 8, 9

REG A, B

REG E, F

0.0625°C/LSB

305.18µVLSB

T

REG 4, 5

REG 6, 7

REG A, B

REG E, F

0.0625°C/LSB

1.295mA/LSB

AMB

BAT

V

I

BAT

T

0.0625°C/LSB

2.5V + 305.18µV/LSB

T

0.0625°C/LSB

2.5V + 305.18µV/LSB

BAT

V

CC

2990f

ꢁ0

LTC2990

Typical applicaTions

Wet-Bulb PscAhrometer

5V

0.1µF

MMBT3904

V2

MMBT3904

V

V1

CC

SDA

SCL

V3

µC

LTC2990

470pF

$T

ADR0

ADR1

V4

2990 TA08

GND

T

DRY

T

WET

T

INTERNAL

FAN: SUNON

KDE0504PFB2

DAMP MUSLIN

CONTROL REGISTER: 0x5D

FAN

T

AMB

T

WET

T

DRY

REG 4, 5

REG 6, 7

REG A, B

REG E, F

0.0625°C/LSB

WATER

RESERVOIR

5V

V

CC

2.5V + 305.18µV/LSB

NDS351AN

FAN ENABLE

REFERENCES:

http://en.wikipedia.org/wiki/Hygrometer

http://en.wikipedia.org/wiki/Psychrometrics

Liquid-Level ꢂndiAator

3.3V

µC

SENSOR HI*

0.1µF

HEATER ENABLE

V

V1

V2

V3

V4

CC

470pF

SDA

SCL

ADR0

ADR1

SENSOR HI

SENSOR LO

LTC2990

GND

SENSOR LO*

$T = ~2.0°C pp, SENSOR HI

~0.2°C pp, SENSOR LO

T

INTERNAL

NDS351AN

HEATER ENABLE

2 SECOND PULSE

HEATER: 75Ω 0.125W

*SENSOR MMBT3904, DIODE CONNECTED

2290 TA09

CONTROL REGISTER: 0x5D

T

REG 4, 5

REG 6, 7

REG A, B

REG E, F

0.0625°C/LSB

AMB

HI

0.0625°C/LSB

LO

V

CC

2.5V + 305.18µV/LSB

2990f

ꢁꢀ

LTC2990

Typical applicaTions

OsAillator/ReferenAe Oven Temperature Regulation

HEATER

= I •V

PWR

0.1Ω

HEATER

VOLTAGE

5V

STYROFOAM

INSULATION

20°C

AMBIENT

0.1µF

V

V1

V2

V3

CC

MMBT3904

HEATER

2-WIRE

SDA

SCL

ADR0

ADR1

2

I C

LTC2990

GND

INTERFACE

470pF

V4

T

OVEN

70°C

OVEN

2990 TA10

T

INTERNAL

HEATER CONSTRUCTION:

HEATER POWER = A • (T

– T

) + B • ∫(T

– T ) dt

SET

AMB

OVEN SET

5FT COIL OF #34 ENAMEL WIRE

~1.6Ω AT 70°C

FEED

BACK

FORWARD

P

= ~0.4W WITH T = 20°C

HEATER

A

A = 0.004W, B = 0.00005W/DEG-s

VOLTAGE AND TEMPERATURE CONFIGURATION:

CURRENT AND TEMPERATURE CONFIGURATION:

CONTROL REGISTER: 0x58

CONTROL REGISTER: 0x59

T

AMB

REG 4, 5

REG 8, 9

REG A, B

REG E, F

0.0625°C/LSB

305.18µVLSB

T

REG 4, 5

REG 6, 7

REG A, B

REG E, F

0.0625°C/LSB

269µVLSB

AMB

V1, V2

I

HEATER

T

0.0625°C/LSB

2.5V + 305.18µV/LSB

T

0.0625°C/LSB

2.5V + 305.18µV/LSB

OVEN

V

CC

Wind DireAtion/ꢂnstrumentation

3.3V

µC

0.1µF

V

MMBT3904 3.3V MMBT3904

V1

V2

V3

CC

SDA

SCL

ADR0

ADR1

LTC2990

470pF

V4

2990 TA11

GND

HEATER

75Ω

0.125W

T

INTERNAL

2N7002

FAN ENABLE

2 SECOND PULSE

CONTROL REGISTER: 0x5D

T

REG 4, 5

REG 8, 9

REG A, B

REG E, F

0.0625°C/LSB

AMB

R1

R2

0.0625°C/LSB

2.5V + 305.18µV/LSB

V

CC

2990f

ꢁꢁ

LTC2990

package DescripTion

MS PaAkage

±0-Lead PlastiA MSOP

(Reference LTC DWG # 05-08-1661 Rev E)

0.889 p 0.127

(.035 p .005)

5.23

(.206)

MIN

3.20 – 3.45

(.126 – .136)

3.00 p 0.102

(.118 p .004)

(NOTE 3)

0.497 p 0.076

(.0196 p .003)

REF

0.50

0.305 p 0.038

(.0120 p .0015)

TYP

(.0197)

10 9

8

7 6

BSC

RECOMMENDED SOLDER PAD LAYOUT

3.00 p 0.102

(.118 p .004)

(NOTE 4)

4.90 p 0.152

(.193 p .006)

DETAIL “A”

0.254

(.010)

0o – 6o TYP

GAUGE PLANE

1

2

3

4 5

0.53 p 0.152

(.021 p .006)

0.86

(.034)

REF

1.10

(.043)

MAX

DETAIL “A”

0.18

(.007)

SEATING

PLANE

0.17 – 0.27

(.007 – .011)

TYP

0.1016 p 0.0508

(.004 p .002)

0.50

(.0197)

BSC

MSOP (MS) 0307 REV E

NOTE:

1. DIMENSIONS IN MILLIMETER/(INCH)

2. DRAWING NOT TO SCALE

3. DIMENSION DOES NOT INCLUDE MOLD FLASH, PROTRUSIONS OR GATE BURRS.

MOLD FLASH, PROTRUSIONS OR GATE BURRS SHALL NOT EXCEED 0.152mm (.006") PER SIDE

4. DIMENSION DOES NOT INCLUDE INTERLEAD FLASH OR PROTRUSIONS.

INTERLEAD FLASH OR PROTRUSIONS SHALL NOT EXCEED 0.152mm (.006") PER SIDE

5. LEAD COPLANARITY (BOTTOM OF LEADS AFTER FORMING) SHALL BE 0.102mm (.004") MAX

2990f

Information furnished by Linear Technology Corporation is believed to be accurate and reliable.

However, no responsibility is assumed for its use. Linear Technology Corporation makes no representa-

tion that the interconnection of its circuits as described herein will not infringe on existing patent rights.

ꢁꢂ

LTC2990

Typical applicaTion

High Voltage/Current and Temperature Monitoring

R

1mΩ

1ꢀ

SENSE

V

IN

5V TO 105V

I

R

±0Ω

1ꢀ

LOAD

IN

0A TO 10A

0.1µF

+IN

–INS

–

+

–INF

V

–

+

V

REG

OUT

LTC610±HV

0.1µF

R

4.99k

1ꢀ

OUT

±00k

1ꢀ

0.1µF

4.75k

1ꢀ

5V

0.1µF

MMBT3904

V

V1

V±

V3

CC

±-WIRE

SDA

SCL

ADR0

ADR1

±

I C

LTC±990

GND

470pF

INTERFACE

V4

±990 TA0±

ALL CAPACITORS ±±0ꢀ

VOLTAGE, CURRENT AND TEMPERATURE CONFIGURATION:

CONTROL REGISTER: 0x58

T

REG 4, 5

REG 6, 7

REG 8, 9

REG A, B

REG E, F

0.06±5°C/LSB

13.±mVLSB

1.±±3mA/LSB

0.06±5°C/LSB

±.5V + 305.18µV/LSB

AMB

V

LOAD

V±(I

)

LOAD

T

REMOTE

V

CC

relaTeD parTs

PꢀRT NUMBER

LM134

DESCRꢂPTꢂON

Constant Current Source and Temperature Sensor

COMMENTS

Can Be Used as Linear Temperature Sensor

LTC1392

Micropower Temperature, Power Supply and Differential Voltage Complete Ambient Temperature Sensor Onboard

Monitor



LTC2487

Internal Temperature Sensor

16-Bit, 2-/4-Channel Delta Sigma ADC with PGA, Easy Drive

2

and I C Interface

LTC6102/LTC6102HV Precision Zero Drift Current Sense Ampliﬁer

Easy Drive is a trademark of Linear Technology Corporation.

5V to 100V, 105V Absolute Maximum (LTC6102HV)

2990f

LT 0910 • PRINTED IN USA

Linear Technology Corporation

1630 McCarthy Blvd., Milpitas, CA 95035-7417

ꢁꢃ

●

ꢀLINEAR TECHNOLOGY CORPORATION 2010

(408) 432-1900 FAX: (408) 434-0507 www.linear.com


型号：	LTC2990IMS
厂家：	Linear
描述：	I2C Temperature, Voltage and Current Monitor I2C温度，电压和电流监视器电源电路电源管理电路监视器光电二极管
文件：	总24页 (文件大小：284K)
中文：	中文翻译
下载：	下载PDF数据表文档文件

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