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.

Features

Accurately senses die temperature of 3 remote ICs, or

diode junctions

On-board local temperature sensing

SMBus and I2C compatible interface, supports

SMBus 1.1 TIMEOUT

Two interrupt outputs: INT and T_CRIT_A

Register readback capability

7 bit plus sign temperature data format, 1 °C resolution

2 address select pins allow connection of 9 LM83s on a

single bus

Key Specifications

Supply Voltage 3.0V to 3.6V

Supply Current 0.8mA (max)

Local Temp Accuracy (includes quantization error)

0°C to +85°C ±3.0°C (max)

Remote Diode Temp Accuracy (includes quantization

error)

+25°C to +100°C ±3°C (max)

0°C to +125°C ±4°C (max)

Applications

System Thermal Management

Computers

Electronic Test Equipment

Office Electronics

HVAC