DS1631, DS1631A

High-Precision Digital Thermometer and Thermostat

High-Precision Digital Thermometers and Thermostats Provide 9, 10, 11, or 12-Bit Temperature Readings Over a -55°C to +125°C Range

Please check latest availability status for a specific part variant.


The DS1631, DS1631A, and DS1731 digital thermometers provide 9, 10, 11, or 12-bit temperature readings over a -55°C to +125°C range. The DS1631 and DS1631A thermometer accuracy is ±0.5°C from 0°C to +70°C with 3.0V ≤ VDD ≤ 5.5V, and the DS1731 accuracy is ±1°C from -10°C to +85°C with 3.0V ≤ VDD ≤ 5.5V. The thermostat on all three devices provides custom hysteresis with user-defined trip points (TH and TL). The TH and TL registers and thermometer configuration settings are stored in NV EEPROM so they can be programmed prior to installation. In addition, the DS1631A automatically begins taking temperature measurements at power-up, which allows it to function as a stand-alone thermostat.
DS1631, DS1631A, DS1731: Functional Diagram DS1631, DS1631A, DS1731: Functional Diagram Enlarge+

Key Features

  • Maximize System Accuracy in Broad Range of Thermal Management Applications
    • Operating Temperature Range: -55°C to +125°C (-67°F to +257°F)
    • DS1631 and DS1631A: ±0.5°C Accuracy over 0°C to +70°C Range
    • DS1731: ±1°C Accuracy over a -10°C to +85°C Range
    • User-Selectable Output Resolution from 9 Bits to 12 Bits
  • Reduce Cost with No External Components
  • Simplify Distributed Temperature-Sensing Applications with Multidrop Capability
    • Up to Eight Devices Can Operate on a 2-Wire Bus
  • Flexible and Nonvolatile User-Defined Thermostatic Modes with Custom Hysteresis
  • Available in 8-Pin µSOP and SO (DS1631 and DS1631A Only) and the 8-Pin DIP (DS1631 Only) Packages


  • Medical
  • Networking
  • Personal Computing
  • Routers/Switches
  • Test Measurement Systems
  • Wireless Base Stations
Part NumberSensor TypeInterfaceChannelsAccuracy
Parasite Pwr.Temp. Thresh.Temp. Resolution
Multi DroppableOper. Temp.
See Notes
DS1631 Local2-Wire/I2C/SMBusOne0.5NoProgrammable (NV)
Yes-55 to +125
SOIC (N)/8
SOIC (W)/8
$1.94 @1k
DS1731 1
$2.15 @500
See All Temperature Sensors (112)
Pricing Notes:
This pricing is BUDGETARY, for comparing similar parts. Prices are in U.S. dollars and subject to change. Quantity pricing may vary substantially and international prices may differ due to local duties, taxes, fees, and exchange rates. For volume-specific and version-specific prices and delivery, please see the price and availability page or contact an authorized distributor.

CAD Symbols and Footprints

  • DS1631+
  • DS1631AU
  • DS1631AU+
  • DS1631AU+T&R
  • DS1631AU/T&R
  • DS1631S
  • DS1631S+
  • DS1631S+T&R
  • DS1631S/T&R
  • DS1631U
  • DS1631U+
  • DS1631U+T&R
  • DS1631U/T&R
  • DS1631Z
  • DS1631Z+
  • DS1631Z+T&R
  • DS1631Z/T&R
  • Device   Fab Process   Technology   Sample size   Rejects   FIT at 25°C   FIT at 55°C  

    Note : The failure rates are summarized by technology and mapped to the associated material part numbers. The failure rates are highly dependent on the number of units tested.

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