LM91

LM91 Diode Input Digital Temperature Sensor with Two-Wire Interface November 2001 LM91 Diode Input Digital Temperature Sensor with Two-Wire Interface General Description The LM91 is a remote diode temperature sensor, Delta-Sigma analog-to-digital converter, and digital over-temperature detector with an SMBus™ interface. The LM91 senses its own temperature as well as the temperature of a target IC with a diode junction, such as a Pentium® II processor or a diode connected 2N3904. A diode junction (semiconductor junction) is required on the target IC’s die. A host can query the LM91 at any time to read the temperature of this diode as well as the temperature state of the LM91 itself. A T_CRIT_A interrupt output becomes active when the temperature is greater than a programmable comparator limit, T_CRIT. The host can program as well as read back the state of the T_CRIT register. Power up default values for T_CRIT are as shown in the ordering information table. Three state logic inputs allow two pins (ADD0, ADD1) to select up to 9 SMBus address locations for the LM91. Features n Directly senses die temperature of remote ICs n Senses temperature of remote diodes n SMBus compatible interface, supports SMBus Timeout n Register readback capability n 7 bit plus sign temperature data format n 2 address select lines enable 9 LM91s to be connected to a single bus Key Specifications j Supply Voltage j Supply Current j Local Temperature Accuracy j Remote Diode Temperature Accuracy +...