LM91  Product Folder

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.

• Directly senses die temperature of remote ICs
• Senses temperature of remote diodes
• SMBus compatible interface, supports SMBus Timeout
• Register readback capability
• 7 bit plus sign temperature data format
• 2 address select lines enable 9 LM91s to be connected to a single bus

• System Thermal Management
• Personal Computers
• Electronic Test Equipment
• Office Electronics
• HVAC