DS1920 Temperature iButton®

Status
Part Number	Status
DS1920	Active: In production, but some versions are no longer available. See Ordering Information.

Description

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The DS1920 provides direct-to-digital 9-bit temperature readings over a range of -55��C to +100��C in 0.5�� increments. The iButton communicates with a processor using the 1-Wire® protocol through a hardware port interface. The port interface provides both the physical link and handles the communication protocols that enable the processor to access iButton resources with simple commands. Two bytes of EEPROM can be used either to set alarm triggers or for storing user data.

Armored in an iButton, the thermometer can measure temperatures in demanding environments. Like every other iButton, the DS1920 has a unique serial number. The 1-Wire interface reduces data output, address, and power to one line. A unique serial number allows multiple 1920s to share the same bus, with many sensors placed at different sites reporting to a single port on a processor. Multidropped DS1920s make the lowest-power temperature sensing network available inside buildings, equipment, or machinery and in process monitoring and control. With appropriate accessories the DS1920 easily attaches to an object or circuit board.

Key Features

Digital Thermometer Measures Temperatures from -55��C to +100��C in Typically 0.2s
Zero Standby Power
0.5��C Resolution, Digital Temperature Reading is Two's Complement of ��C Value
Access to Internal Counters Allows Increased Resolution Through Interpolation
Reduces control, Address, Data, and Power to a Single Data Contact
8-Bit Device-Generated CRC for Data Integrity
8-Bit Family Code Specifies DS1920 Communications Requirements to Reader
Special Command Set Allows User to Skip ROM Section and Perform Temperature Measurements Simultaneously for All Devices on the Bus
2 Bytes of EEPROM to Be Used Either as Alarm Triggers or User Memory
Alarm Search Directly Indicates Which Device Senses Alarming Temperatures