MAXIM LM75 service manual

General Description

The LM75 temperature sensor includes a delta-sigma analog-to-digital converter, and a digital overtemperature detector. The host can query the LM75 through its I2C interface to read temperature at any time. The open-drain overtemperature output (OS) sinks current when the programmable temperature limit is exceeded. The OS output operates in either of two modes, comparator or interrupt. The host controls the temperature at which the alarm is asserted (TOS) and the hysteresis temperature below which the alarm condition is not valid (T

HYST

). Also, the LM75’s TOSand T

HYST

registers can be read by the host. The address of the LM75 is set with three pins to allow multiple devices to work on the same bus. Power-up is in comparator mode, with defaults of TOS= +80°C and T

HYST

= +75°C. The 3.0V to 5.5V supply voltage range, low supply current, and I2C interface make the LM75 ideal for many applications in thermal management and protection.

Applications

Thermal System Management Thermal Protection Test Equipment Computers and Office Electronics

Features

♦ SO (SOP) and µMAX®(µSOP) Packages ♦ I2C Bus Interface ♦ Separate Open-Drain OS Output Operates as

Interrupt or Comparator/Thermostat Input

♦ Register Readback Capability ♦ Power-Up Defaults Permit Stand-Alone Operation

as a Thermostat

♦ 3.0V to 5.5V Supply Voltage ♦ Low Operating Supply Current 250µA (typ), 1mA

(max)

♦ 4µA (typ) Shutdown Mode Minimizes Power

Consumption

♦ Up to Eight LM75s Can Be Connected to a Single

Bus

♦ Pin- and/or Register-Compatible with Improved-

Performance Maxim Sensors Including MAX7500, MAX6625, MAX6626, DS75LV, and DS7505

LM75

Digital Temperature Sensor and Thermal

Watchdog with 2-Wire Interface

________________________________________________________________

Maxim Integrated Products

Functional Diagram

Ordering Information/Selector Guide

19-4385; Rev 0; 3/09

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.

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

Note: Devices are specified over the -55°C to +125°C temperature range and include I

C noise filter.

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

T&R = Tape and reel.

Pin Configuration

TOP VIEW

SDA

SCL

μMAX (μSOP), SO

LM75

A2GND

= 3.0V to 5.5V

SILICON

9-BIT DELTA-

BANDGAP

TEMPERATURE

SIGMA ADC

SENSOR

CONFIGURATION

8816 16 16

TOS SET POINT

POINTER

2-WIRE INTERFACE

SET POINT

COMPARATOR W/

HYSTERESIS

SET

HYST

POINT REGISTER

SDA

SCL

PART PIN-PACKAGE PKG SUPPLY VOLTAGE (V) TOP MARK

LM75BIM-3+ 8 SO (SOP) Bulk 3.3 LM75BIM-3

LM75BIMX-3+ 8 SO (SOP) T&R 3.3 LM75BIM-3

LM75BIMM-3+ 8 µMAX (µSOP) Bulk 3.3 T01B

LM75BIMMX-3+ 8 µMAX (µSOP) T&R 3.3 T01B

LM75BIM-5+ 8 SO (SOP) Bulk 5.0 LM75BIM-5

LM75BIMX-5+ 8 SO (SOP) T&R 5.0 LM75BIM-5

LM75BIMM-5+ 8 µMAX (µSOP) Bulk 5.0 T00B

LM75BIMMX-5+ 8 µMAX (µSOP) T&R 5.0 T00B

LM75

Digital Temperature Sensor and Thermal Watchdog with 2-Wire Interface

2 _______________________________________________________________________________________

ABSOLUTE MAXIMUM RATINGS (Note 1)

ELECTRICAL CHARACTERISTICS

(+VS= +3.0V to +5.5V, unless otherwise noted. Temperature accuracy specifications apply for +VS= 3.3V for versions with “-3” in the suffix and for +V

= 5V for versions with “-5” in the suffix. TA= -55°C to +125°C, unless otherwise noted. Typical values are at

= +5V, TA= +25°C.) (Notes 4, 5)

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.

+VSto GND ...........................................................-0.3V to +6.0V

OS, SDA, SCL to GND...........................................-0.3V to +6.0V

All Other Pins to GND.................................-0.3V to (+V

+ 0.3V)

Input Current at Any Pin (Note 2)..........................................5mA

Package Input Current (Note 2)..........................................20mA

OS Output Sink Current ......................................................10mA

Continuous Power Dissipation (T

= +70°C) (Note 3) 8-Pin µMAX (µSOP)

(derate 4.5mW/°C above +70°C)..................................362mW

8-Pin SO (SOP) (derate 5.9mW/°C above +70°C) ........471mW

Junction-to-Case Thermal Resistance (θ

) (Note 3)

8-Pin µMAX (µSOP).......................................................42°C/W

8-Pin SO (SOP)..............................................................40°C/W

Junction-to-Ambient Thermal Resistance (θ

) (Note 3)

8-Pin µMAX (µSOP).....................................................221°C/W

8-Pin SO (SOP)............................................................170°C/W

ESD Protection Human Body Model (R

= 1.5kΩ, CS= 100pF)

All Pins to GND .................................................................±2kV

Operating Temperature Range .........................-55°C to +125°C

Junction Temperature......................................................+150°C

Storage Temperature Range .............................-65°C to +150°C

Lead Temperature (soldering, 10s) .................................+300°C

Note 1: Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. DC and AC electrical specifica-

tions do not apply when operating the device beyond its rated operating conditions.

Note 2: When the input voltage (V

) at any pin exceeds the Absolute Maximum Ratings limits (VI< GND, VI> 6V or VI> +VS), the current at that pin should be limited to 5mA. The 20mA maximum package input current rating limits the number of pins that can safely exceed the power supplies with an input current of 5mA to four.

Note 3: Package thermal resistances were obtained using the method described in JEDEC specification JESD51-7, using a single-

layer board. For detailed information on package thermal considerations, refer to www.maxim-ic.com/thermal-tutorial

Accuracy (Six-Sigma)

Accuracy (Three-Sigma) (Note 6)

Resolution 9 Bits

Temperature Conversion Time (Note 7) 100 300 ms

Quiescent Supply Current

+VS Supply Voltage Range 3.0 5.5 V

OS Output Saturation Voltage I

OS Delay (Note 9) 1 6

OS Output Fall Time t

TOS Default Temperature (Note 11) 80 °C

HYST

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Default Temperature (Note 11) 75 °C

-25°C ≤ TA ≤ +100°C -2.0 +2.0

≤ +125°C -3.0 +3.0

≤ +125°C -2.0 +2.0

= 5V 6

= 4.0mA (Note 8) 0.8 V

Conver-

sions

-55°C ≤ T

-25°C ≤ TA ≤ +100°C -1.5 +1.5

-55°C ≤ T

I2C inactive 0.25 0.5 mA

Shutdown mode, +VS = 3V 4

Shutdown mode, +V

OUT

CL = 400pF, IO = 3mA (Note 10) 250 ns

°C

µA

LM75

Digital Temperature Sensor and Thermal

Watchdog with 2-Wire Interface

_______________________________________________________________________________________ 3

ELECTRICAL CHARACTERISTICS (continued)

(+VS= +3.0V to +5.5V, unless otherwise noted. Temperature accuracy specifications apply for +VS= 3.3V for versions with “-3” in the suffix and for +V

= 5V for versions with “-5” in the suffix. TA= -55°C to +125°C, unless otherwise noted. Typical values are at

= +5V, TA= +25°C.) (Notes 4, 5)

Note 4: All parts operate properly over the 3V to 5.5V supply voltage range. The devices are tested and specified for rated

accuracy at their nominal supply voltage.

Note 5: All parameters are measured at T

= +25°C. Values over the temperature range are guaranteed by design.

Note 6: There is no industry-wide standard for temperature accuracy specifications. Maxim’s standard is six-sigma. The three-

sigma specification is included to allow easier comparison to products built by manufacturers who use different standards.

Note 7: This specification indicates how often temperature data is updated. The devices can be read at any time without regard to

conversion state, while yielding the last conversion result.

Note 8: For best accuracy, minimize output loading. Higher sink currents can affect sensor accuracy due to internal heating. Note 9: OS delay is user programmable up to 6 over-limit conversions before OS is set to minimize false tripping in noisy environ-

ments.

Note 10: Guaranteed by design. Note 11: Default values set at power-up. Note 12: All timing specifications are guaranteed by design. Note 13: Unless otherwise noted, these specifications apply for +V

= +5VDC for LM75BIM-5 and LM75BIMM-5 and +VS=

+3.3VDC for LM75BIM-3 and LM75BIMM-3. C

(load capacitance) on output lines = 80pF, unless otherwise specified. The switching characteristics of the LM75 fully meet or exceed the published specifications of the I2C bus. These parameters are the timing relationships between SCL and SDA signals related to the LM75. They are not I

C bus specifications.

Note 14: Holding the SDA line low for a time greater than t

TIMEOUT

causes the device to reset SDA to the IDLE state of the

serial bus communication (SDA set high).

LOGIC (SDA, SCL, A0, A1, A2)

Input High Voltage V

Input Low Voltage V

Input High Current I

Input Low Current I

Input Capacitance C

Output High Current VOH = 5V 10 µA

Output Low Voltage IOL = 3mA 0.4 V

I2C-COMPATIBLE TIMING (Notes 12, 13)

(Clock) SCL Period t

Data In Setup Time to SCL High t

Data Out Stable After SCL Low t

Start Condition Setup Time (SDA Low to SCL Low)

STOP Condition Hold Time t

SDA Time Low for Reset of Serial Interface

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

SCL

SU:DAT

HD:DAT

SU:STA

HD:STO

TIMEOUT

+VS x

0.7

-0.3

VIN = 5V 0.005 1.0 µA

VIN = 0V -1.0 -0.005 µA

All digital inputs 20 pF

Bus timeout inactive 2.5 µs

10% of SDA to 10% of SCL 100 ns

10% of SCL to 10% of SDA 0 µs

90% of SCL to 90% of SDA 100 ns

100 ns

(Note 14) 75 325 ms

+VS +

0.5

0.3

QUIESCENT SUPPLY CURRENT

vs. TEMPERATURE

LM75 toc01

TEMPERATURE (°C)

QUIESCENT SUPPLY CURRENT (μA)

9565355-25

240

250

260

270

280

290

300

230

-55 125

+VS = +5V

+VS = +3V

SHUTDOWN SUPPLY CURRENT (μA)

SHUTDOWN SUPPLY CURRENT

vs. TEMPERATURE

LM75 toc02

TEMPERATURE (°C)

9565355-25-55 125

+VS = +5V

+VS = +3V

ACCURACY vs. TEMPERATURE

ACCURACY (°C)

-1.5

-1.0

-0.5

0.5

1.0

1.5

2.0

-2.0

LM75 toc03

TEMPERATURE (°C)

9565355-25-55 125

4 TYPICAL PARTS

Typical Operating Characteristics

(TA = +25°C, unless otherwise noted.)

LM75

Digital Temperature Sensor and Thermal Watchdog with 2-Wire Interface

4 _______________________________________________________________________________________

Pin Description

PIN NAME FUNCTION

1 SDA Serial-Data Input/Output Line. Open drain. Connect SDA to a pullup resistor.

2 SCL Serial Clock Input. Open drain. Connect SCL to a pullup resistor.

3 OS Overtemperature Shutdown Output. Open drain. Connect OS to a pullup resistor.

4 GND Ground

5A2

6A1

7A0

8+VSPositive Supply Voltage Input. Bypass to GND with a 0.1µF bypass capacitor.

2-Wire Interface Address Input. Connect A2 to GND or +V leave unconnected (see Table 1).

2-Wire Interface Address Input. Connect A1 to GND or +V leave unconnected (see Table 1).

2-Wire Interface Address Input. Connect A0 to GND or +V leave unconnected (see Table 1).

to set the desired I2C bus address. Do not

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