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LM75B, LM75C

www.ti.com

SNIS153B –JULY 2009–REVISED MARCH 2013

LM75B

LM75C Digital Temperature Sensor and Thermal Watchdog with Two-Wire Interface

Check for Samples: LM75B, LM75C

FEATURES

DESCRIPTION

The LM75B and LM75C are industy-standard digital

• No External Components Required

temperature sensors with an integrated Sigma-Delta

• Shutdown Mode to Minimize Power

analog-to-digital converter and I

C interface. The

Consumption

LM75 provides 9-bit digital temperature readings with

• Up to Eight LM75s Can be Connected to a

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

Communication is accomplished over a 2-wire

Operation as Thermostat

interface which operates up to 400kHz. The LM75

has three address pins, allowing up to eight LM75

• UL Recognized Component (LM75B and

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

LM75C)

LM75 has a dedicated over-temperature output (O.S.)

with programmable limit and hystersis. This output

APPLICATIONS

has programmable fault tolerance, which allows the

• General System Thermal Management

user to define the number of consecutive error

conditions that must occur before O.S. is activated.

• Communications Infrastructure

The wide temperature and supply range and I

• Electronic Test Equipment

interface make the LM75 ideal for a number of

• Environmental Monitoring

applications including base stations, electronic test

equipment, office electronics, personal computers,

KEY SPECIFICATIONS

and any other system where thermal management is

• Supply Voltage critical to performance. The LM75B and LM75C are

available in an SOIC package or VSSOP package.

– LM75B, LM75C: 3.0V to 5.5V

• Supply Current

– 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)

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 (23 pages)

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LM75B, LM75C www.ti.com SNIS153B – JULY 2009 – REVISED MARCH 2013 LM75B LM75C Digital Temperature Sensor and Thermal Watchdog with Two-Wire Interface Check for Samples: LM75B, LM75C FEATURES DESCRIPTION • • The LM75B and LM75C are industy-standard digital temperature sensors with an integrated Sigma-Delta analog-to-digital converter and I2C interface. The LM75 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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LM75B, LM75C SNIS153B – JULY 2009 – REVISED MARCH 2013 www.ti.com Simplified Block Diagram +VS 8 Temperature 10-Bit Digital Decimation Filter Ð 1-Bit D/A TOS Set Point Set Point Comparator Reset Silicon Bandgap Temperature Sensor A1 A2 O.S. Threshold Register 9-Bit Sigma-Delta ADC A0 3 Configuration Register Pointer Register THYST Set Point Register 1 7 6 Two-Wire Interface 5 2 SDA SCL 4 GND Figure 1.
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LM75B, LM75C www.ti.com SNIS153B – JULY 2009 – REVISED MARCH 2013 Typical Application +VS 100 nF (typ) unless mounted close to processor 8 A0 Address A1 (Set as desired) A2 Interface SDA SCL 7 6 5 LM75 3 O.S. To Processor Interrupt Line 1 O.S. set to active low IRU ZLUH 25¶G PXOWLSOH interrupt line 2 4 GND Figure 2. Typical Application These devices have limited built-in ESD protection.
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LM75B, LM75C SNIS153B – JULY 2009 – REVISED MARCH 2013 www.ti.com Device Number Package Number Thermal Resistance (θJA) LM75BIM-3, LM75BIM-5, LM75CIM-3, LM75CIM-5 D (R-PDSO-G8) 200°C/W LM75BIMM-3, LM75BIMM-5, LM75CIMM-3, LM75CIMM-5 DGK (S-PDSOG8) 250°C/W Temperature-to-Digital Converter Characteristics (1) Unless otherwise noted, these specifications apply for: +VS = +5 Vdc for LM75BIM-5, LM75BIMM-5, LM75CIM-5, and LM75CIMM-5; and +VS = +3.
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LM75B, LM75C www.ti.com SNIS153B – JULY 2009 – REVISED MARCH 2013 Logic Electrical Characteristics DIGITAL DC CHARACTERISTICS Unless otherwise noted, these specifications apply for +VS = +5 Vdc for LM75BIM-5, LM75BIMM-5, LM75CIM-5, and LM75CIMM-5; and +VS = +3.3 Vdc for LM75BIM-3, LM75BIMM-3, LM75CIM-3, and LM75CIMM-3 (1). Boldface limits apply for TA = TJ = TMIN to TMAX; all other limits TA = TJ = +25°C, unless otherwise noted.
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LM75B, LM75C SNIS153B – JULY 2009 – REVISED MARCH 2013 www.ti.com Figure 3. Figure 4. Temperature-to-Digital Transfer Function (Non-linear scale for clarity) Figure 5.
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LM75B, LM75C www.ti.com SNIS153B – JULY 2009 – REVISED MARCH 2013 TYPICAL PERFORMANCE CHARACTERISTICS Static Quiescent Current vs Temperature (LM75C) Dynamic Quiescent Current vs Temperature (LM75C) Figure 6. Figure 7. Accuracy vs Temperature (LM75C) Figure 8.
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LM75B, LM75C SNIS153B – JULY 2009 – REVISED MARCH 2013 www.ti.com FUNCTIONAL DESCRIPTION The LM75 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 LM75 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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LM75B, LM75C www.ti.com SNIS153B – JULY 2009 – REVISED MARCH 2013 These interrupt mode resets of O.S. occur only when LM75 is read or placed in shutdown. Otherwise, O.S. would remain active indefinitely for any event. Figure 9. 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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LM75B, LM75C SNIS153B – JULY 2009 – REVISED MARCH 2013 www.ti.com COMPARATOR/INTERRUPT MODE As indicated in the O.S. Output Temperature Response Diagram, Figure 9, 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 LM75. O.S. OUTPUT The O.S.
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LM75B, LM75C www.ti.com SNIS153B – JULY 2009 – REVISED MARCH 2013 An inadvertent 8-bit read from a 16-bit register, with the D7 bit low, can cause the LM75 to stop in a state where the SDA line is held low as shown in Figure 11. This can prevent any further bus communication until at least 9 additional clock cycles have occurred. Alternatively, the master can issue clock cycles until SDA goes high, at which time issuing a “Stop” condition will reset the LM75. Figure 11.
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LM75B, LM75C SNIS153B – JULY 2009 – REVISED MARCH 2013 www.ti.com D5–D7: These bits are used for production testing and must be kept zero for normal operation. 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 = TEST CIRCUIT DIAGRAMS Figure 12.
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LM75B, LM75C www.ti.com SNIS153B – JULY 2009 – REVISED MARCH 2013 Figure 13.
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LM75B, LM75C SNIS153B – JULY 2009 – REVISED MARCH 2013 www.ti.com APPLICATION HINTS To get the expected results when measuring temperature with an integrated circuit temperature sensor like the LM75, it is important to understand that the sensor measures its own die temperature. For the LM75, the best thermal path between the die and the outside world is through the LM75's pins.
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LM75B, LM75C www.ti.com SNIS153B – JULY 2009 – REVISED MARCH 2013 + 5 VDC Heater Heater Supply C1 100 nF R2 10k Optional but Recommended Pull-up In Stand-alone Mode 8 R1 +VS 10k K1 5V Relay D1 1N4001 A0 7 A1 6 A2 5 LM75 Q1 2N2222A 3 O.S. SDA 1 SCL 2 4 GND Figure 15.
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LM75B, LM75C SNIS153B – JULY 2009 – REVISED MARCH 2013 www.ti.com REVISION HISTORY Changes from Revision A (March 2013) to Revision B • 16 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 1-Nov-2013 (2) Eco Plan - The planned eco-friendly classification: Pb-Free (RoHS), Pb-Free (RoHS Exempt), or Green (RoHS & no Sb/Br) - please check http://www.ti.com/productcontent for the latest availability information and additional product content details. TBD: The Pb-Free/Green conversion plan has not been defined.
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PACKAGE MATERIALS INFORMATION www.ti.com 23-Sep-2013 TAPE AND REEL INFORMATION *All dimensions are nominal Device Package Package Pins Type Drawing SPQ Reel Reel A0 Diameter Width (mm) (mm) W1 (mm) B0 (mm) K0 (mm) P1 (mm) W Pin1 (mm) Quadrant LM75BIMM-3 VSSOP DGK 8 1000 178.0 12.4 5.3 3.4 1.4 8.0 12.0 Q1 LM75BIMM-3/NOPB VSSOP DGK 8 1000 178.0 12.4 5.3 3.4 1.4 8.0 12.0 Q1 LM75BIMM-5 VSSOP DGK 8 1000 178.0 12.4 5.3 3.4 1.4 8.0 12.
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PACKAGE MATERIALS INFORMATION www.ti.com 23-Sep-2013 *All dimensions are nominal Device Package Type Package Drawing Pins SPQ Length (mm) Width (mm) Height (mm) LM75BIMM-3 VSSOP DGK 8 1000 210.0 185.0 35.0 LM75BIMM-3/NOPB VSSOP DGK 8 1000 210.0 185.0 35.0 LM75BIMM-5 VSSOP DGK 8 1000 210.0 185.0 35.0 LM75BIMM-5/NOPB VSSOP DGK 8 1000 210.0 185.0 35.0 LM75BIMMX-3 VSSOP DGK 8 3500 367.0 367.0 35.0 LM75BIMMX-3/NOPB VSSOP DGK 8 3500 367.0 367.0 35.
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