DS18B20 1-wire temperature sensor

Description

The DS18B20 Digital Thermometer provides 9 to12-bit centigrade 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.

Key Features

• Unique 1-Wire® interface requires only one port pin for communication
• Each device has a unique 64-bit serial code stored in an onboard 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 from 9 to 12 bits
• Converts temperature to 12-bit digital word in 750ms (max.)
• User-definable nonvolatile (NV) alarm settings
• Alarm search command identifies and addresses devices whose temperature is outside of programmed limits (temperature alarm condition)
• Available in 8-pin SO (150mil), 8-pin µSOP, and 3-pin TO-92 packages
• Software compatible with the DS1822
• Applications include thermostatic controls, industrial systems, consumer products, thermometers, or any thermally sensitive system

Applications

• Agricultural Equipment
• Audio Equipment
• Automotive
• Climate Control
• GPS Devices
• Hard Disk Drive
• Medical Equipment
• Set-Top Boxes
• Telecommunications