General Description
The MAX1668/MAX1805/MAX1989 are precise multichannel digital thermometers that report the temperature of all remote sensors and their own packages. The remote sensors are diode-connected transistors—typically low-cost, easily mounted 2N3904 NPN types—that replace conventional thermistors or thermocouples. Remote accuracy is ±3°C for multiple transistor manufacturers, with no calibration needed. The remote channels can also measure the die temperature of other ICs, such as microprocessors, that contain an on-chip, diode-connected transistor.

Features
♦ Multichannel
    4 Remote, 1 Local (MAX1668/MAX1989)
    2 Remote, 1 Local (MAX1805)
♦ No Calibration Required
♦ SMBus 2-Wire Serial Interface
♦ Programmable Under/Overtemperature Alarms
♦ Supports SMBus Alert Response
♦ Accuracy
    ±2°C (+60°C to +100°C, Local)
    ±3°C (-40°C to +125°C, Local)
    ±3°C (+60°C to +100°C, Remote)
♦ 3µA (typ) Standby Supply Current
♦ 700µA (max) Supply Current
♦ Small, 16-Pin QSOP/TSSOP Packages

Applications
    Desktop and Notebook Computers
    LAN Servers
    Industrial Controls
    Central-Office Telecom Equipment
    Test and Measurement
    Multichip Modules