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Multichannel Remote/Local Temperature Sensors

Product Details

Key Features

Parametric specs for Temperature Sensors
Sensor Type Remote
# Channels Four
Interface 2-Wire/I2C/SMBus
Alarm Output Alert
Functions Remote & Local Sensor
Accuracy (±°C) 2
Parasite Pwr. No
Temp. Resolution (bits) 8
Oper. Temp. (°C) -55 to +125
Package/Pins QSOP/16
TSSOP/16
Budgetary
Price (See Notes)
4.25
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Simplified Block Diagram

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Parameters

Parametric specs for Temperature Sensors
Sensor Type Remote
# Channels Four
Interface 2-Wire/I2C/SMBus
Alarm Output Alert
Functions Remote & Local Sensor
Accuracy (±°C) 2
Parasite Pwr. No
Temp. Resolution (bits) 8
Oper. Temp. (°C) -55 to +125
Package/Pins QSOP/16
TSSOP/16
Budgetary
Price (See Notes)
4.25

Key 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/Uses

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

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.

The 2-wire serial interface accepts standard system management bus (SMBus™) write byte, read byte, send byte, and receive byte commands to program the alarm thresholds and to read temperature data. The data format is 7 bits plus sign, with each bit corresponding to 1°C, in two's-complement format.

The MAX1668/MAX1805/MAX1989 are available in small, 16-pin QSOP surface-mount packages. The MAX1989 is also available in a 16-pin TSSOP.

Simplified Block Diagram

MAX1668, MAX1805, MAX1989: Typical Operating Circuit MAX1668, MAX1805, MAX1989: Typical Operating Circuit Zoom icon

Technical Docs

Support & Training

Search our knowledge base for answers to your technical questions.

Filtered Search

Our dedicated team of Applications Engineers are also available to answer your technical questions. Visit our support portal .