General Description
The LM84 is a remote diode temperature sensor,
Delta-Sigma analog-to-digital converter, and digital
over-temperature detector with an SMBus™ interface. The
LM84 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 LM84 at any time to read the temperature
of this diode as well as the temperature state of the LM84
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. Three state logic inputs allow two pins
(ADD0, ADD1) to select up to 9 SMBus address locations for
the LM84. The sensor powers up with default thresholds of
127°C for T_CRIT.

Features
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 LM84s to be connected
to a single bus

Key Specifications
Supply Voltage 3.0V - 3.6V
Supply Current 1 mA (max)
Local Temperature Accuracy ±1.0°C (typ)
Remote Diode Temperature Accuracy
+60°C to +100°C ±3°C (max)
0°C to +125°C ±5°C (max)

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