DS18B20 1-Wire Digital Thermometer Sensor

The DS18B20 digital thermometer provides 9-bit to 12-bit Celsius temperature measurements and has an alarm function with nonvolatile user- programmable upper and lower trigger points. The DS18B20 communicates over a 1-Wire bus that by definition requires only one data line (and ground) for communication with a central microprocessor. It has an operating temperature range of -55°C to +125°C and is accurate to ±0.5°C over the range of -10°C to +85°C. In addition, the DS18B20 can derive power directly from the data line (“parasite power”), eliminating the need for an external power supply.

Each DS18B20 has a unique 64-bit serial code, which allows multiple DS18B20s to function on the same 1-Wire bus. Thus, it is simple to use one microprocessor to control many DS18B20s distributed over a large area. Applications that can benefit from this feature include HVAC environmental controls, temperature monitoring systems inside buildings, equipment, or machinery, and process monitoring and control systems.

Specifications

• Unique 1-Wire® Interface Requires Only One Port Pin for Communication
• Each Device has a Unique 64-Bit Serial Code Stored in an On- Board ROM
• Multidrop Capability Simplifies Distributed Temperature-Sensing Applications
• Requires No External Components
• Can Be Powered from Data Line; Power Supply Range is 3.0V to 5.5V
• Measures Temperatures from -55°C to +125°C (-67°F to +257°F)
• ±0.5°C Accuracy from -10°C to +85°C
• Thermometer Resolution is User Selectable Pin Configurations appear at end of data sheet. 
• from 9 to 12 Bits
• Functional Diagrams continued at end of data sheet.