MAX31820PAR

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


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.
MAX31820PAR: Block Diagram MAX31820PAR: Block Diagram Enlarge+

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
Part Number Sensor Type Interface Channels Accuracy
(±°C)
Parasite Pwr. Temp. Thresh. Temp. Resolution
(bits)
Multi Droppable Oper. Temp.
(°C)
Package/Pins Budgetary
Price
See Notes
MAX31820PAR  Local 1-Wire One 0.5 Yes Programmable (NV)
9
10
11
12
Yes -55 to +100
TO92/3
$1.12 @1k
See All Temperature Sensors (112)
Pricing Notes:
This pricing is BUDGETARY, for comparing similar parts. Prices are in U.S. dollars and subject to change. Quantity pricing may vary substantially and international prices may differ due to local duties, taxes, fees, and exchange rates. For volume-specific and version-specific prices and delivery, please see the price and availability page or contact an authorized distributor.

Technical Documents

Reference Schematic 5508 Create a 1-Wire Master with Xilinx PicoBlaze
App Note 5507 Understanding the DS1WM Synthesizable 1-Wire Bus Master
Tutorial 4700 Introduction to Medical Instruments and Growing Trend for Point-of-Care and Near-Patient Testing
Tutorial 4699 Overview of Sensor Signal Paths
Tutorial 4679 Thermal Management Handbook
App Note 4600 Simple Software Validates the Hardware CRC and Detects Errors in the Serial Bit Stream of 1-Wire® Thermal Devices
Reference Schematic 4477 Reference Design of a 1-Wire® Bidirectional Voltage-Level Translator for 1.8V to 5V
App Note 4377 Comparison of the DS18B20 and DS18S20 1-Wire® Digital Thermometers
App Note 4277 Getting Started with the MAXQ2000 USB Thumb Evaluation Kit
App Note 4255 How to Power the Extended Features of 1-Wire® Devices
App Note 3930 Package Thermal Resistance Values (Theta JA, Theta JC) for Temperature Sensors and 1-Wire Devices
App Note 3754 Single-Wire Serial Bus Carries Isolated Power and Data
App Note 2965 1-Wire Master Device Configuration
App Note 2420 1-Wire Communication with a Microchip PICmicro Microcontroller
App Note 1100 White Paper 5: Using 1-Wire APIs for Data Sheet Commands
Reference Schematic 244 Advanced 1-Wire Network Driver
App Note 208 Curve Fitting the Error of a Bandgap-Based Digital Temperature Sensor
App Note 203 DS18B20-PAR/DS18S20-PAR/DS1822-PAR Advantages for Remote Temperature Sensing
App Note 192 Using the DS2480B Serial 1-Wire® Line Driver
App Note 187 1-Wire Search Algorithm
App Note 162 Interfacing the DS18X20/DS1822 1-Wire® Temperature Sensor in a Microcontroller Environment
App Note 158 1-Wire® Tagging with XML
Tutorial 148 Guidelines for Reliable Long Line 1-Wire Networks
App Note 126 1-Wire Communication Through Software
App Note 27 Understanding and Using Cyclic Redundancy Checks with Maxim 1-Wire and iButton Products

Quality and Environmental Data

Request Reliability Report for: MAX31820PAR 
Lead-Free Package Tin (Sn) Whisker Reports

Related Resources

Type ID PDF Title
Reference Schematic 5508 Create a 1-Wire Master with Xilinx PicoBlaze
App Note 5507 Understanding the DS1WM Synthesizable 1-Wire Bus Master
Tutorial 4700 Introduction to Medical Instruments and Growing Trend for Point-of-Care and Near-Patient Testing
Tutorial 4699 Overview of Sensor Signal Paths
Tutorial 4679 Thermal Management Handbook
App Note 4600 Simple Software Validates the Hardware CRC and Detects Errors in the Serial Bit Stream of 1-Wire® Thermal Devices
Reference Schematic 4477 Reference Design of a 1-Wire® Bidirectional Voltage-Level Translator for 1.8V to 5V
App Note 4377 Comparison of the DS18B20 and DS18S20 1-Wire® Digital Thermometers
App Note 4277 Getting Started with the MAXQ2000 USB Thumb Evaluation Kit
App Note 4255 How to Power the Extended Features of 1-Wire® Devices
App Note 3930 Package Thermal Resistance Values (Theta JA, Theta JC) for Temperature Sensors and 1-Wire Devices
App Note 3754 Single-Wire Serial Bus Carries Isolated Power and Data
App Note 2965 1-Wire Master Device Configuration
App Note 2420 1-Wire Communication with a Microchip PICmicro Microcontroller
App Note 1100 White Paper 5: Using 1-Wire APIs for Data Sheet Commands
Reference Schematic 244 Advanced 1-Wire Network Driver
App Note 208 Curve Fitting the Error of a Bandgap-Based Digital Temperature Sensor
App Note 203 DS18B20-PAR/DS18S20-PAR/DS1822-PAR Advantages for Remote Temperature Sensing
App Note 192 Using the DS2480B Serial 1-Wire® Line Driver
App Note 187 1-Wire Search Algorithm
App Note 162 Interfacing the DS18X20/DS1822 1-Wire® Temperature Sensor in a Microcontroller Environment
App Note 158 1-Wire® Tagging with XML
Tutorial 148 Guidelines for Reliable Long Line 1-Wire Networks
App Note 126 1-Wire Communication Through Software
App Note 27 Understanding and Using Cyclic Redundancy Checks with Maxim 1-Wire and iButton Products