Overview
Features and Benefits
- Unique 1-Wire® Interface Requires Only One Port Pin for Communication
- Reduce Component Count with Integrated Temperature Sensor and EEPROM
- Measures Temperatures from -55°C to +125°C (-67°F to +257°F)
- ±0.5°C Accuracy from -10°C to +85°C
- Programmable Resolution from 9 Bits to 12 Bits
- No External Components Required
- Parasitic Power Mode Requires Only 2 Pins for Operation (DQ and GND)
- Simplifies Distributed Temperature-Sensing Applications with Multidrop Capability
- Each Device Has a Unique 64-Bit Serial Code Stored in On-Board ROM
- Flexible User-Definable Nonvolatile (NV) Alarm Settings with Alarm Search Command Identifies Devices with Temperatures Outside Programmed Limits
- Available in 8-Pin SO (150 mils), 8-Pin µSOP, and 3-Pin TO-92 Packages
Product Details
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. 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.
How to Spatially Index 1-Wire® Sensors Using the MAXREFDES131 and DS18B20

Applications
- Consumer Products
- Industrial Systems
- Thermally Sensitive Systems
- Thermometers
- Thermostatic Controls
Product Lifecycle
Production
At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.
Evaluation Kits (2)
Documentation & Resources
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UG-4277: Getting Started with the MAXQ2000 USB Thumb Evaluation Kit9/24/2008PDF301K
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1-Wire Search Algorithm3/28/2002
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How to Use Packet-Error Checking to Secure Your Temperature Reading3/26/2019
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Wirelessly Powering and Accessing a 1-Wire Network3/14/2019
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Simple Software Validates the Hardware CRC and Detects Errors in the Serial Bit Stream of 1-Wire® Thermal Devices9/25/2009
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Comparison of the DS18B20 and DS18S20 1-Wire® Digital Thermometers3/18/2009
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Single-Wire Serial Bus Carries Isolated Power and Data3/23/2006
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Using Dallas' 1-Wire ICs in 1-Cell Li-Ion Battery Packs With Low-Side N-Channel Safety FETs Master4/25/2001
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NEW
Create a 1-Wire Master with Xilinx PicoBlaze2/27/2023
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NEW
Advanced 1-Wire Network Driver2/14/2023
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How to Get Data Out of Your Favorite Sensors10/6/2016
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Overview of Sensor Signal Paths5/12/2010
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Introduction to Medical Instruments and Growing Trend for Point-of-Care and Near-Patient Testing5/10/2010
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Thermal Management Handbook5/4/2010
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How to Power the Extended Features of 1-Wire® Devices6/17/2008
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Package Thermal Resistance Values (Theta JA, Theta JC) for Temperature Sensors and 1-Wire Devices11/16/2006
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1-Wire Master Device Configuration3/3/2004
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1-Wire Communication with a Microchip PICmicro Microcontroller9/16/2003
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Curve Fitting the Error of a Bandgap-Based Digital Temperature Sensor6/20/2002
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White Paper 5: Using 1-Wire APIs for Data Sheet Commands6/7/2002
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1-Wire® Tagging with XML6/7/2002
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1-Wire Communication Through Software5/30/2002
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Using the DS2480B Serial 1-Wire® Line Driver3/12/2002
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Interfacing the DS18X20/DS1822 1-Wire® Temperature Sensor in a Microcontroller Environment3/8/2002
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Understanding and Using Cyclic Redundancy Checks with Maxim 1-Wire and iButton Products3/29/2001
Design Resources
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PCN-PDN Information
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Evaluation Boards
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Pricing displayed is based on 1-piece. The USA list pricing shown is for budgetary use only, shown in United States dollars (FOB USA per unit), and is subject to change. International prices may vary due to local duties, taxes, fees and exchange rates.