Top

1-Wire Parasite-Power, Ambient Temperature Sensor

Parasite-Powered Digital Temperature Sensor in TO-92 Package Minimizes Wiring and is Ideal for Measuring Ambient Temperature

Product Details

The MAX31820PAR ambient temperature sensor provides 9-bit to 12-bit Celsius temperature measurements with ±0.5°C accuracy over a +10°C to +45°C temperature range. Over its entire -55°C to +125°C operating range, the device has ±2.0°C accuracy.

The device 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 device derives power directly from the data line (“parasite power”), eliminating the need for an external power supply. Requiring so few pins enables the device to be placed in a 3-pin TO-92 package. The form factor of this package allows the device to be placed above the board and thus measure the ambient temperature of a system, as opposed to the board temperature that a surface-mount package would measure.

Each MAX31820PAR has a unique 64-bit serial code, which allows multiple MAX31820PAR devices to function on the same 1-Wire bus. Therefore, it is simple to use one microprocessor to control many devices distributed over a large area.

Key Features

  • Unique 1-Wire Interface Requires Only One Port Pin for Communication
  • Derives Power from Data Line (Parasite Power); No Local Power Supply Needed
  • Multidrop Capability Simplifies Distributed Temperature-Sensing Applications
  • Requires No External Components
  • Measures Temperatures from -55°C to +125°C (-67°F to +257°F)
  • ±0.5°C Accuracy from +10°C to +45°C
  • Thermometer Resolution is User-Selectable from 9 Bits 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 Programmed Limits (Temperature Alarm Condition)
  • Available in 3-Pin TO-92 Package
  • Software Compatible with the DS1822-PAR and DS18B20-PAR

Applications/Uses

  • Any Thermally Sensitive System
  • Consumer Products
  • HVAC Environmental Controls
  • Industrial Systems
  • Process Monitoring and Control Systems
  • Temperature Monitoring Systems Inside Buildings, Equipment, or Machinery
  • Thermometers
  • Thermostatic Controls
Parametric specs for Temperature Sensors
Sensor Type Local
# Channels One
Interface 1-Wire
Accuracy (±°C) 0.5
Parasite Pwr. Yes
Temp. Thresh. Programmable (NV)
Temp. Resolution (bits) 9
10
11
12
Oper. Temp. (°C) -55 to +100
Package/Pins TO92/3
Budgetary
Price (See Notes)
$1.18 @1k
View More

Simplified Block Diagram

MAX31820PAR: Block Diagram MAX31820PAR: Block Diagram Zoom icon

Technical Docs

Data Sheet 1-Wire Parasite-Power, Ambient Temperature Sensor Jun 28, 2013
Reference Schematic Create a 1-Wire Master with Xilinx PicoBlaze
App Note Understanding the DS1WM Synthesizable 1-Wire Bus Master
Tutorial Introduction to Medical Instruments and Growing Trend for Point-of-Care and Near-Patient Testing
Tutorial Overview of Sensor Signal Paths
Tutorial Thermal Management Handbook
App Note Simple Software Validates the Hardware CRC and Detects Errors in the Serial Bit Stream of 1-Wire® Thermal Devices
Reference Schematic Reference Design of a 1-Wire® Bidirectional Voltage-Level Translator for 1.8V to 5V
App Note Comparison of the DS18B20 and DS18S20 1-Wire® Digital Thermometers
App Note Getting Started with the MAXQ2000 USB Thumb Evaluation Kit
App Note Package Thermal Resistance Values (Theta JA, Theta JC) for Temperature Sensors and 1-Wire Devices
App Note Single-Wire Serial Bus Carries Isolated Power and Data
App Note 1-Wire Master Device Configuration
App Note 1-Wire Communication with a Microchip PICmicro Microcontroller
App Note White Paper 5: Using 1-Wire APIs for Data Sheet Commands
Reference Schematic Advanced 1-Wire Network Driver
App Note Curve Fitting the Error of a Bandgap-Based Digital Temperature Sensor
App Note DS18B20-PAR/DS18S20-PAR/DS1822-PAR Advantages for Remote Temperature Sensing
App Note Using the DS2480B Serial 1-Wire® Line Driver
App Note 1-Wire Search Algorithm
App Note Interfacing the DS18X20/DS1822 1-Wire® Temperature Sensor in a Microcontroller Environment
App Note 1-Wire® Tagging with XML
Tutorial Guidelines for Reliable Long Line 1-Wire Networks
App Note 1-Wire Communication Through Software
App Note Understanding and Using Cyclic Redundancy Checks with Maxim 1-Wire and iButton Products

Design & Development

Click any title below to view the detail page where available.

/en/design/design-tools/ee-sim.html?

Support & Training

Search our knowledge base for answers to your technical questions.

Filtered Search

Our dedicated team of Applications Engineers are also available to answer your technical questions. Visit our support portal

Parameters

Parametric specs for Temperature Sensors
Sensor Type Local
# Channels One
Interface 1-Wire
Accuracy (±°C) 0.5
Parasite Pwr. Yes
Temp. Thresh. Programmable (NV)
Temp. Resolution (bits) 9
10
11
12
Oper. Temp. (°C) -55 to +100
Package/Pins TO92/3
Budgetary
Price (See Notes)
$1.18 @1k

Key Features

  • Unique 1-Wire Interface Requires Only One Port Pin for Communication
  • Derives Power from Data Line (Parasite Power); No Local Power Supply Needed
  • Multidrop Capability Simplifies Distributed Temperature-Sensing Applications
  • Requires No External Components
  • Measures Temperatures from -55°C to +125°C (-67°F to +257°F)
  • ±0.5°C Accuracy from +10°C to +45°C
  • Thermometer Resolution is User-Selectable from 9 Bits 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 Programmed Limits (Temperature Alarm Condition)
  • Available in 3-Pin TO-92 Package
  • Software Compatible with the DS1822-PAR and DS18B20-PAR

Applications/Uses

  • Any Thermally Sensitive System
  • Consumer Products
  • HVAC Environmental Controls
  • Industrial Systems
  • Process Monitoring and Control Systems
  • Temperature Monitoring Systems Inside Buildings, Equipment, or Machinery
  • Thermometers
  • Thermostatic Controls

Description

The MAX31820PAR ambient temperature sensor provides 9-bit to 12-bit Celsius temperature measurements with ±0.5°C accuracy over a +10°C to +45°C temperature range. Over its entire -55°C to +125°C operating range, the device has ±2.0°C accuracy.

The device 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 device derives power directly from the data line (“parasite power”), eliminating the need for an external power supply. Requiring so few pins enables the device to be placed in a 3-pin TO-92 package. The form factor of this package allows the device to be placed above the board and thus measure the ambient temperature of a system, as opposed to the board temperature that a surface-mount package would measure.

Each MAX31820PAR has a unique 64-bit serial code, which allows multiple MAX31820PAR devices to function on the same 1-Wire bus. Therefore, it is simple to use one microprocessor to control many devices distributed over a large area.

Simplified Block Diagram

MAX31820PAR: Block Diagram MAX31820PAR: Block Diagram Zoom icon

Technical Docs

Data Sheet 1-Wire Parasite-Power, Ambient Temperature Sensor Jun 28, 2013
Reference Schematic Create a 1-Wire Master with Xilinx PicoBlaze
App Note Understanding the DS1WM Synthesizable 1-Wire Bus Master
Tutorial Introduction to Medical Instruments and Growing Trend for Point-of-Care and Near-Patient Testing
Tutorial Overview of Sensor Signal Paths
Tutorial Thermal Management Handbook
App Note Simple Software Validates the Hardware CRC and Detects Errors in the Serial Bit Stream of 1-Wire® Thermal Devices
Reference Schematic Reference Design of a 1-Wire® Bidirectional Voltage-Level Translator for 1.8V to 5V
App Note Comparison of the DS18B20 and DS18S20 1-Wire® Digital Thermometers
App Note Getting Started with the MAXQ2000 USB Thumb Evaluation Kit
App Note Package Thermal Resistance Values (Theta JA, Theta JC) for Temperature Sensors and 1-Wire Devices
App Note Single-Wire Serial Bus Carries Isolated Power and Data
App Note 1-Wire Master Device Configuration
App Note 1-Wire Communication with a Microchip PICmicro Microcontroller
App Note White Paper 5: Using 1-Wire APIs for Data Sheet Commands
Reference Schematic Advanced 1-Wire Network Driver
App Note Curve Fitting the Error of a Bandgap-Based Digital Temperature Sensor
App Note DS18B20-PAR/DS18S20-PAR/DS1822-PAR Advantages for Remote Temperature Sensing
App Note Using the DS2480B Serial 1-Wire® Line Driver
App Note 1-Wire Search Algorithm
App Note Interfacing the DS18X20/DS1822 1-Wire® Temperature Sensor in a Microcontroller Environment
App Note 1-Wire® Tagging with XML
Tutorial Guidelines for Reliable Long Line 1-Wire Networks
App Note 1-Wire Communication Through Software
App Note Understanding and Using Cyclic Redundancy Checks with Maxim 1-Wire and iButton Products

Support & Training

Search our knowledge base for answers to your technical questions.

Filtered Search

Our dedicated team of Applications Engineers are also available to answer your technical questions. Visit our support portal