LM83

LM83 Triple-Diode Input and Local Digital Temperature Sensor with Two-Wire Interface November 1999 LM83 Triple-Diode Input and Local Digital Temperature Sensor with Two-Wire Interface General Description The LM83 is a digital temperature sensor with a 2 wire serial interface that senses the voltage and thus the temperature of three remote diodes using a Delta-Sigma analog-to-digital converter with a digital over-temperature detector. The LM83 accurately senses its own temperature as well as the temperature of three external devices, such as Pentium II ® Processors or diode connected 2N3904s. The temperature of any ASIC can be detected using the LM83 as long as a dedicated diode (semiconductor junction) is available on the die. Using the SMBus interface a host can access the LM83’s registers at any time. Activation of a T_CRIT_A output occurs when any temperature is greater than a programmable comparator limit, T_CRIT. Activation of an INT output occurs when any temperature is greater than its corresponding programmable comparator HIGH limit. The host can program as well as read back the state of the T_CRIT register and the four T_HIGH registers. Three state logic inputs allow two pins (ADD0, ADD1) to select up to 9 SMBus address locations for the LM83. The sensor powers up with default thresholds of 127˚C for T_CRIT and all T_HIGHs. The LM83 is pin for pin and register compatible with the LM84 as well as the Maxim MAX1617 and the Analog Devices ADM1021. n On-board local tem...