LM90

Features:

`Accurately senses die temperature of remote ICs or diode junctions
`Offset register allows sensing a variety of thermal diodes accurately
`On-board local temperature sensing
`10 bit plus sign remote diode temperature data format, 0.125 resolution
`Diode fault detection circuitry
`T_CRIT_A output useful for system shutdown (open diode does not activate T_CRIT_A )
`ALERT output supports SMBus 2.0 protocol
`SMBus 2.0 compatible interface, supports TIMEOUT
`8-pin MSOP packages




Application

·System Thermal Management (e.g. Laptop, Desktop, Workstations, Server)
·Electronic Test Equipment
·Office Electronics




Pinout






Specifications

Supply Voltage -0.3 V to 6.0 V
Voltage at SMBData, SMBCLK,
ALERT , T_CRIT_A -0.5V to 6.0V
Voltage at Other Pins -0.3 V to
(VDD + 0.3 V)
D- Input Current ±1 mA
Input Current at All Other Pins (Note 2) ±5 mA
Package Input Current (Note 2) 30 mA
SMBData,ALERT , T_CRIT_A Output
Sink Current 10 mA
Storage Temperature -65 to
+150
Soldering Information, Lead Temperature
SOIC-8 or MSOP-8 Packages (Note 3)
Vapor Phase (60 seconds) 215
Infrared (15 seconds) 220
ESD Susceptibility (Note 4)
Human Body Model 2000 V
Machine Model 200 V

Remote Diode Thermal Sensors	1
Temperature Accuracy (+/-)	3 deg C
Supply Min	3 Volt
Quiescent Current	1.7 mA
Temperature Min	0 deg C
Temperature Max	125 deg C
Interface Type	2-Wire Serial
Programmable Setpoints	Yes
Resolution	11 bits
Resolution degC/LSB	0.125
Supply Max	3.6 Volt
Shut down	Yes
Interrupt Outputs	2
Fault Queue	Yes
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Description

The LM90 is an 11-bit digital temperature sensor with a 2-wire System Management Bus (SMBus) serial interface. The LM90 accurately measures its own temperature as well as the temperature of an external device, such as processor thermal diode or diode connected transistor such as the 2N3904. The temperature of any ASIC can be accurately determined using the LM90 as long as a dedicated diode (semiconductor junction) is available on the target die. The LM90 remote sensor accuracy of ±3 is factory trimmed for the 1.008 typical non-ideality factor of the mobile Pentium^TM III thermal diode. The LM90 has an Offset register to allow measuring other diodes without requiring continuous software management. Contact hardware.monitor.team@nsc.com to obtain the latest data for new processors.
Activation of the ALERT output occurs when any temperature goes outside a preprogrammed window set by the HIGH and LOW temperature limit registers or exceeds the T_CRIT temperature limit. Activation of the T_CRIT_A occurs when any temperature exceeds the T_CRIT programmed limit. The LM90 is pin and register compatible with the LM86, Analog Devices ADM1032 and Maxim MAX6657/8.