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.
View datasheet View product folder