LM77

Features:

`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
`SOP and MSOP 8-lead packages

Application

·System Thermal Management
·Personal Computers
·Office Electronics
·Electronic Test Equipment
·Automotive
·HVAC




Pinout






Specifications

The LM7Supply Voltage -0.3V to 6.5V
Voltage at any Pin -0.3V to (+VS + 0.3V)
Input Current at any Pin 5 mA
Package Input Current (Note 2) 20 mA
T_CRIT_A and INT Output Sink
Current 10 mA
T_CRIT_A and INT Output
Voltage 6.5V
Storage Temperature -65 to +125
Soldering Information, Lead
Temperature
SOP and MSOP Package (Note 3)
Vapor Phase (60 seconds) 215
Infrared (15 seconds) 220
ESD Susceptibility (Note 4)
Human Body Model 2500V
Machine Model 250V




Description

The LM77 is a digital temperature sensor and thermal window comparator with an I²C^TM 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 T_HYST, 10 T_LOW, 64 T_HIGH, and 80 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 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.