Datasheet

ManualsBrandsTEXAS INSTRUMENTS ManualsPMICsLM75AIM/NOPB

Temperature

Threshold

Silicon Bandgap

Temperature

Sensor

1-Bit

D/A

10-Bit

Digital

Decimation

Filter

9-Bit Sigma-Delta ADC

Configuration

Set Point

Pointer

HYST

Set

Point Register

Set Point

Comparator

O.S.

Reset

SDA

SCL

Two-Wire Interface

GND

Product ID

LM75A

www.ti.com

SNOS808O –JANUARY 2000–REVISED MAY 2013

LM75A Digital Temperature Sensor and Thermal Watchdog with Two-Wire Interface

Check for Samples: LM75A

FEATURES

DESCRIPTION

The LM75A is an industry-standard digital

• No External Components Required

temperature sensor with an integrated Sigma-Delta

• Shutdown Mode to Minimize Power

analog-to-digital converter and I

C interface. The

Consumption

LM75A provides 9-bit digital temperature readings

• Up to Eight LM75As can be Connected to a

with an accuracy of ±2°C from -25°C to 100°C and

±3°C over -55°C to 125°C.

Single Bus

• Power Up Defaults Permit Stand-Alone

The LM75A operates with a single supply from +2.7V

Operation as Thermostat

to +5.5V. Communication is accomplished over a 2-

wire interface which operates up to 400kHz. The

LM75A has three address pins, allowing up to eight

APPLICATIONS

LM75A devices to operate on the same 2-wire bus.

• General System Thermal Management

The LM75A has a dedicated over-temperature output

• Communications Infrastructure

(O.S.) with programmable limit and hysteresis. This

output has programmable fault tolerance, which

• Electronic Test Equipment

allows the user to define the number of consecutive

• Environmental Monitoring

error conditions that must occur before O.S. is

activated. The wide temperature and supply range

KEY SPECIFICATIONS

and I

C interface make the LM75A ideal for a number

of applications including base stations, electronic test

• Supply Voltage

equipment, office electronics, personal computers,

– LM75A: 2.7V to 5.5V

and any other system where thermal management is

• Supply Current

critical to performance. The LM75A is available in an

SOIC-8 package and an VSSOP-8 package.

– Operating: 280 μA (Typ)

– Shutdown: 4 μA (Typ)

• Temperature Accuracy

– 25°C to 100°C: ±2°C (Max)

– 55°C to 125°C: ±3°C (Max)

SIMPLIFIED BLOCK DIAGRAM

Figure 1.

Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of

Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.

2All trademarks are the property of their respective owners.

PRODUCTION DATA information is current as of publication date.

Products conform to specifications per the terms of the Texas

Instruments standard warranty. Production processing does not

necessarily include testing of all parameters.

Summary of content (21 pages)

PAGE 1
LM75A www.ti.com SNOS808O – JANUARY 2000 – REVISED MAY 2013 LM75A Digital Temperature Sensor and Thermal Watchdog with Two-Wire Interface Check for Samples: LM75A FEATURES DESCRIPTION • • The LM75A is an industry-standard digital temperature sensor with an integrated Sigma-Delta analog-to-digital converter and I2C interface. The LM75A provides 9-bit digital temperature readings with an accuracy of ±2°C from -25°C to 100°C and ±3°C over -55°C to 125°C.
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LM75A SNOS808O – JANUARY 2000 – REVISED MAY 2013 www.ti.com CONNECTION DIAGRAMS Figure 2. SOIC-8 and VSSOP-8 Packages See Package Numbers D0008A and DGK0008A Pin Descriptions Label Pin No. Function Typical Connection SDA 1 I2C Serial Bi-Directional Data Line, Open Drain SCL 2 I2C Clock Input From Controller, tied to a pull-up resistor or current source O.S.
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LM75A www.ti.com SNOS808O – JANUARY 2000 – REVISED MAY 2013 ABSOLUTE MAXIMUM RATINGS (1) −0.3V to 6.5V Supply Voltage Pin (+VS) −0.3V to (+VS + 0.3V) and must be ≤ 6.5V Voltage at A0, A1and A2 Pins −0.3V to 6.5V Voltage at OS, SCL and SDA Pins Input Current at any Pin (2) Package Input Current 5 mA (2) 20 mA −65°C to +150°C Storage Temperature Human Body Model ESD Susceptibility (3) LM75A 2500V Machine Model 250V Charged Device Model 1000V O.S. Output Sink Current 10 mA O.S.
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LM75A SNOS808O – JANUARY 2000 – REVISED MAY 2013 www.ti.com TEMPERATURE-TO-DIGITAL CONVERTER CHARACTERISTICS Unless otherwise noted, these specifications apply for: +VS = +2.7 to 5.5 Vdc for LM75AIM. Boldface limits apply for TA = TJ = TMIN to TMAX; all other limits TA = TJ = +25°C, unless otherwise noted. Parameter Conditions Accuracy Typical (1) TA = −25°C to +100°C ±2.0 TA = −55°C to +125°C ±3.
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LM75A www.ti.com SNOS808O – JANUARY 2000 – REVISED MAY 2013 I2C DIGITAL SWITCHING CHARACTERISTICS Unless otherwise noted, these specifications apply for +VS = +2.7 to 5.5 Vdc for LM75AIM and LM75AIMM on output lines = 80 pF unless otherwise specified. Boldface limits apply for TA = TJ = TMIN to TMAX; all other limits TA = TJ = +25°C, unless otherwise noted. Symbol Parameter Conditions Typical (1) Limits (2) (3) Units (Limit) t1 SCL (Clock) Period 2.
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LM75A SNOS808O – JANUARY 2000 – REVISED MAY 2013 www.ti.com Figure 6. Printed Circuit Board Used for Thermal Resistance Specifications TYPICAL PERFORMANCE CHARACTERISTICS Accuracy vs Temperature (LM75A) Figure 7.
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LM75A www.ti.com SNOS808O – JANUARY 2000 – REVISED MAY 2013 FUNCTIONAL DESCRIPTION The LM75A temperature sensor incorporates a band-gap type temperature sensor and 9-bit ADC (Sigma-Delta Analog-to-Digital Converter). The temperature data output of the LM75A is available at all times via the I2C bus. If a conversion is in progress, it will be stopped and restarted after the read.
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LM75A SNOS808O – JANUARY 2000 – REVISED MAY 2013 www.ti.com These interrupt mode resets of O.S. occur only when LM75A is read or placed in shutdown. Otherwise, O.S. would remain active indefinitely for any event. Figure 8. O.S. Output Temperature Response Diagram TEMPERATURE DATA FORMAT Temperature data can be read from the Temperature, TOS Set Point, and THYST Set Point registers; and written to the TOS Set Point, and THYST Set Point registers.
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LM75A www.ti.com SNOS808O – JANUARY 2000 – REVISED MAY 2013 COMPARATOR/INTERRUPT MODE As indicated in the O.S. Output Temperature Response Diagram, Figure 8, the events that trigger O.S. are identical for either Comparator or Interrupt mode. The most important difference is that in Interrupt mode the O.S. will remain set indefinitely once it has been set. To reset O.S. while in Interrupt mode, perform a read from any register in the LM75A. O.S. OUTPUT The O.S.
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LM75A SNOS808O – JANUARY 2000 – REVISED MAY 2013 www.ti.com The first data byte is the most significant byte with most significant bit first, permitting only as much data as necessary to be read to determine temperature condition. For instance, if the first four bits of the temperature data indicates an overtemperature condition, the host processor could immediately take action to remedy the excessive temperatures.
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LM75A www.ti.com SNOS808O – JANUARY 2000 – REVISED MAY 2013 THYST AND TOS REGISTER (Read/Write): D15 D14 D13 D12 D11 D10 D9 D8 D7 D6 D5 D4 D3 D2 D1 D0 MSB Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 LSB X X X X X X X D0–D6: Undefined 75°C D7–D15: THYST Or TOS Trip Temperature Data. Power up default is TOS = 80°C, THYST = PRODID: PRODUCT ID REGISTER (Read Only) Pointer Address: 07h D7 D6 D5 D4 D3 D2 D1 D0 1 0 1 0 0 0 0 1 D4--D7 Product Identification Nibble.
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LM75A SNOS808O – JANUARY 2000 – REVISED MAY 2013 www.ti.com Figure 11. Timing Diagrams (Continued) APPLICATION HINTS To get the expected results when measuring temperature with an integrated circuit temperature sensor like the LM75A, it is important to understand that the sensor measures its own die temperature. For the LM75A, the best thermal path between the die and the outside world is through the LM75A's pins.
PAGE 13
LM75A www.ti.com SNOS808O – JANUARY 2000 – REVISED MAY 2013 TYPICAL APPLICATIONS +VS +12V C1 100 nF R3 10k Optional but Recommended Pull-up In Stand-alone Mode R1 10k +12V/300 mA Fan Motor R2 10k 8 A0 7 A1 6 3 O.S. A2 5 Q2 NDP410A series Q1 2N3904 LM75A SDA 1 SCL 2 4 GND When using the two-wire interface: program O.S. for active high and connect O.S. directly to Q2's gate. Figure 12.
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LM75A SNOS808O – JANUARY 2000 – REVISED MAY 2013 www.ti.com REVISION HISTORY Changes from Revision N (May 2013) to Revision O • 14 Page Changed layout of National Data Sheet to TI format ..........................................................................................................
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PACKAGE OPTION ADDENDUM www.ti.
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PACKAGE OPTION ADDENDUM www.ti.com 18-Oct-2013 (6) Lead/Ball Finish - Orderable Devices may have multiple material finish options. Finish options are separated by a vertical ruled line. Lead/Ball Finish values may wrap to two lines if the finish value exceeds the maximum column width. Important Information and Disclaimer:The information provided on this page represents TI's knowledge and belief as of the date that it is provided.
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PACKAGE MATERIALS INFORMATION www.ti.com 8-May-2013 TAPE AND REEL INFORMATION *All dimensions are nominal Device Package Package Pins Type Drawing LM75AIMM/NOPB VSSOP DGK 8 LM75AIMME/NOPB VSSOP DGK LM75AIMMX/NOPB VSSOP DGK LM75AIMX/NOPB SOIC D SPQ Reel Reel A0 Diameter Width (mm) (mm) W1 (mm) B0 (mm) K0 (mm) P1 (mm) W Pin1 (mm) Quadrant 1000 178.0 12.4 5.3 3.4 1.4 8.0 12.0 Q1 8 250 178.0 12.4 5.3 3.4 1.4 8.0 12.0 Q1 8 3500 330.0 12.4 5.3 3.4 1.4 8.0 12.
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PACKAGE MATERIALS INFORMATION www.ti.com 8-May-2013 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) LM75AIMM/NOPB VSSOP DGK 8 1000 210.0 185.0 35.0 LM75AIMME/NOPB VSSOP DGK 8 250 210.0 185.0 35.0 LM75AIMMX/NOPB VSSOP DGK 8 3500 367.0 367.0 35.0 LM75AIMX/NOPB SOIC D 8 2500 367.0 367.0 35.
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