The LM82 is a digital temperature sensor with a 2 wire serial interface that senses the voltage and thus the temperature of a remote diode using a Delta-Sigma analog-to-digital converter with a digital over-temperature detector. The LM82 accurately senses its own temperature as well as the temperature of external devices, such as Pentium II Processors or diode connected 2N3904s. The temperature of any ASIC can be detected using the LM82 as long as a dedicated diode (semiconductor junction) is available on the die. Using the SMBus interface a host can access the LM82'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 2 T_HIGH registers. Three state logic inputs allow two pins (ADD0, ADD1) to select up to 9 SMBus address locations for the LM82. The sensor powers up with default thresholds of 127°C for T_CRIT and all T_HIGHs. The LM82 is pin for pin and register compatible with the LM84, Maxim MAX1617 and Analog Devices ADM1021.

• Accurately Senses Die Temperature of 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 LM82s on a Single Bus

Key Specifications

• Supply Voltage: 3.0 to 3.6V
• Supply Current: 0.8mA (max)
• Local Temp Accuracy (includes quantization error):
  • 0 to +85 ±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)