Product details

Local sensor accuracy (Max) (+/- C) 1.5 Type Local Operating temperature range (C) -55 to 125 Supply voltage (Min) (V) 3 Interface type I2C, SMBus Supply voltage (Max) (V) 5.5 Supply current (Max) (uA) 500 Temp resolution (Max) (bits) 10 Remote channels (#) 0 Addresses 4 Rating Catalog
Local sensor accuracy (Max) (+/- C) 1.5 Type Local Operating temperature range (C) -55 to 125 Supply voltage (Min) (V) 3 Interface type I2C, SMBus Supply voltage (Max) (V) 5.5 Supply current (Max) (uA) 500 Temp resolution (Max) (bits) 10 Remote channels (#) 0 Addresses 4 Rating Catalog
SOIC (D) 8 19 mm² 4.9 x 3.9 VSSOP (DGK) 8 15 mm² 3 x 4.9
  • Window Comparison Simplifies Design of ACPI Compatible Temperature Monitoring and Control.
  • Serial Bus Interface
  • Separate Open-Drain Outputs for Interrupt and Critical Temperature Shutdown
  • Shutdown Mode to Minimize Power Consumption
  • Up to 4 LM77s Can be Connected to a Single Bus
  • 9-bit + Sign Output; Full-Scale Reading of Over 128°C
  • SOIC and VSSOP 8-lead Packages

Key Specifications

  • Supply Voltage 3.0V to 5.5V
  • Supply Current
    • Operating250 μA (typ)500 μA (max)
    • Shutdown5 μA (typ)
  • Temperature Accuracy
    • −10°C to 65°C, ±1.5°C(max)
    • −25°C to 100°C, ±2°C(max)
    • −55°C to 125°C, ±3°C(max)

All trademarks are the property of their respective owners.

  • Window Comparison Simplifies Design of ACPI Compatible Temperature Monitoring and Control.
  • Serial Bus Interface
  • Separate Open-Drain Outputs for Interrupt and Critical Temperature Shutdown
  • Shutdown Mode to Minimize Power Consumption
  • Up to 4 LM77s Can be Connected to a Single Bus
  • 9-bit + Sign Output; Full-Scale Reading of Over 128°C
  • SOIC and VSSOP 8-lead Packages

Key Specifications

  • Supply Voltage 3.0V to 5.5V
  • Supply Current
    • Operating250 μA (typ)500 μA (max)
    • Shutdown5 μA (typ)
  • Temperature Accuracy
    • −10°C to 65°C, ±1.5°C(max)
    • −25°C to 100°C, ±2°C(max)
    • −55°C to 125°C, ±3°C(max)

All trademarks are the property of their respective owners.

The LM77 is a digital temperature sensor and thermal window comparator with an I2C Serial Bus interface. The window-comparator architecture of the LM77 eases the design of temperature control systems conforming to the ACPI (Advanced Configuration and Power Interface) specification for personal computers. The open-drain Interrupt (INT) output becomes active whenever temperature goes outside a programmable window, while a separate Critical Temperature Alarm (T_CRIT_A) output becomes active when the temperature exceeds a programmable critical limit. The INT output can operate in either a comparator or event mode, while the T_CRIT_A output operates in comparator mode only.

The host can program both the upper and lower limits of the window as well as the critical temperature limit. Programmable hysterisis as well as a fault queue are available to minimize false tripping. Two pins (A0, A1) are available for address selection. The sensor powers up with default thresholds of 2°C THYST, 10°C TLOW, 64°C THIGH, and 80°C T_CRIT.

The LM77's 3.0V to 5.5V supply voltage range, Serial Bus interface, 9-bit + sign output, and full-scale range of over 128°C make it ideal for a wide range of applications. These include thermal management and protection applications in personal computers, electronic test equipment, office electronics, automotive, and HVAC applications.

The LM77 is a digital temperature sensor and thermal window comparator with an I2C Serial Bus interface. The window-comparator architecture of the LM77 eases the design of temperature control systems conforming to the ACPI (Advanced Configuration and Power Interface) specification for personal computers. The open-drain Interrupt (INT) output becomes active whenever temperature goes outside a programmable window, while a separate Critical Temperature Alarm (T_CRIT_A) output becomes active when the temperature exceeds a programmable critical limit. The INT output can operate in either a comparator or event mode, while the T_CRIT_A output operates in comparator mode only.

The host can program both the upper and lower limits of the window as well as the critical temperature limit. Programmable hysterisis as well as a fault queue are available to minimize false tripping. Two pins (A0, A1) are available for address selection. The sensor powers up with default thresholds of 2°C THYST, 10°C TLOW, 64°C THIGH, and 80°C T_CRIT.

The LM77's 3.0V to 5.5V supply voltage range, Serial Bus interface, 9-bit + sign output, and full-scale range of over 128°C make it ideal for a wide range of applications. These include thermal management and protection applications in personal computers, electronic test equipment, office electronics, automotive, and HVAC applications.

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Technical documentation

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Type Title Date
* Data sheet 9Bit + Dig Temp Sens & Thermal Window Comparator w/Two-Wire Interface datasheet (Rev. F) 22 Mar 2013
Technical article How to choose the right thermistor for your temperature sensing application 13 Feb 2020
Technical article How to enable thermal safety for automotive infotainment and cluster systems 15 Oct 2019
Technical article Driving industrial innovation with small-size sensors 12 Sep 2019
Technical article How to select a temperature sensor probe 18 Feb 2016
Application note Applying I2C-Compatible Temperature Sensors in Systems With Slow Clock Edges (Rev. A) 06 May 2013

Design & development

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Driver or library

LM77SW-LINUX — Linux Driver for LM77

The Linux driver support the LM77 Temperature Sensor. The Linux driver supports communication through the I²C bus and interfaces with the Hardware Monitoring sub-system.
Linux Mainline Status

Available in Linux Main line: Yes
Available through git.ti.com: N/A

Supported Devices:
  • lm77
Linux Source Files

The (...)

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SOIC (D) 8 View options
VSSOP (DGK) 8 View options

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