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AD8497:  Full K-Type Range 25° to 100° Thermocouple Amplifier w/Cold Junction Compensation

Product Details

Product Status:Recommended for New Designs

The AD8494/AD8495/AD8496/AD8497 are precision instrumentation amplifiers with thermocouple cold junction compensators on an integrated circuit. They produce a high level (5 mV/°C) output directly from a thermocouple signal by combining an ice point reference with a precalibrated amplifier. They can be used as standalone thermometers or as switched output setpoint controllers using either a fixed or remote setpoint control.

The AD8494/AD8495/AD8496/AD8497 can be powered from a single-ended supply (less than 3 V) and can measure temperatures below 0°C by offsetting the reference input. To minimize self-heating, an unloaded AD849x typically operates with a total supply current of 180 μA, but it is also capable of delivering in excess of ±5 mA to a load.

The AD8494 and AD8496 are precalibrated by laser wafer trimming to match the characteristics of J type (iron-constantan) thermocouples; the AD8495 and AD8497 are laser trimmed to match the characteristics of K type (chromel-alumel) thermo-couples. See Table 1 on the data sheet for the optimized ambient temperature range of each part.

The AD8494/AD8495/AD8496/AD8497 allow a wide variety of supply voltages. With a 5 V single supply, the 5 mV/°C output allows the devices to cover nearly 1000 degrees of a thermo-couple’s temperature range.

The AD8494/AD8495/AD8496/AD8497 work with 3 V supplies, allowing them to interface directly to lower supply ADCs. They can also work with supplies as large as 36 V in industrial systems that require a wide common-mode input range.

Product Highlights

  1. Complete, precision laser wafer trimmed thermocouple signal conditioning system in a single IC package.
  2. Flexible pinout provides for operation as a setpoint controller or as a standalone Celsius thermometer.
  3. Rugged inputs withstand 4 kV ESD and provide over-voltage protection (OVP) up to VS ± 25 V.
  4. Differential inputs reject common-mode noise on the thermocouple leads.
  5. Reference pin voltage can be offset to measure 0°C on single supplies.
  6. Available in a small, 8-lead MSOP that is fully RoHS compliant.

Applications

  • K type thermocouple temperature measurement
  • Setpoint controller
  • Celsius thermometer
  • Universal cold junction compensator
  • White goods (oven, stove top) temperature measurements
  • Exhaust gas temperature sensing
  • Catalytic converter temperature sensing

FEATURES and BENEFITS

  • Chinese data sheet available
  • Low cost and easy to use
  • Pretrimmed for K type thermocouples
  • Internal cold junction compensation
  • High impedance differential input
  • Standalone 5 mV/°C thermometer
  • Reference pin allows offset adjustment
  • Thermocouple break detection
  • See data sheet for additional features.

Functional Block Diagram

Video: AD849x Series: Thermocouple Amps with Cold Junction Compensation



The AD8494/AD8495/AD8496/AD8497 are easy to use amplifiers for J and K type thermocouples. The AD849x series performs cold junction compensation using an on-board temperature sensor. Learn more by watching the AD849x video.

Documentation

Title Content Type File Type
AD8494/AD8495/AD8496/AD8497: Precision Thermocouple Amplifiers with Cold Junction Compensation Data Sheet (Rev C, 06/2011) (pdf, 2214 kB) Data Sheets PDF
AN-1087: Thermocouple Linearization When Using the AD8495/AD8496/AD8497  (PDF, 126 kB) Application Notes PDF
Two Ways to Measure Temperature Using Thermocouples Feature Simplicity, Accuracy, and Flexibility  (pdf)
(Analog Dialogue 44-10, October 2010)
Tutorials PDF
Design Techniques for reducing power consumption and harmful thermal events in industrial designs
This webcast will present: typical analog module configuration and show how to calculate the maximum ambient temperature that the system can tolerate, new technology to reduce the power dissipated in the module (regardless of what output load is connected), then look at the performance of these devices when the supply is run from a switching regulator rather than with a linear regulator.
Webcasts WEBCAST
Two Ways to Measure Temperature Using Thermocouples Feature Simplicity, Accuracy, and Flexibility  (pdf)
(Analog Dialogue 44-10, October 2010)
Technical Articles PDF
RAQs index Rarely Asked Questions HTML
Glossary of EE Terms Glossary HTML

Design Tools,Models,Drivers & Software

Title Content Type File Type
AD849x Thermocouple Nonlinearity Error Calculator Design Calculators HTML
AD8497 SPICE Macro-Model SPICE Models HTML

Evaluation Kits & Symbols & Footprints

Symbols and Footprints— Analog Devices offers Symbols & Footprints which are compatible with a large set of today’s CAD systems for broader and easier support.

SampleSample & Buy

Price, packaging, availability

AD8497 Model Options
Model Package Pins Temp.
Range
Packing,
Qty
Price*(100-499) Price*1000 pcs RoHS View PCN/ PDN Check Inventory/
Purchase/Sample
AD8497ARMZ Status: Production 8 ld MSOP 8 Ind Tube, 50 $2.19 $1.75 Y  Material Info Notify Me Purchase Sample
AD8497ARMZ-R7 Status: Production 8 ld MSOP 8 Ind Reel, 1000 $2.19 $1.75 Y  Material Info Notify Me Purchase
AD8497CRMZ Status: Production 8 ld MSOP 8 Ind Tube, 50 $3.88 $3.10 Y  Material Info Notify Me Purchase Sample
AD8497CRMZ-R7 Status: Production 8 ld MSOP 8 Ind Reel, 1000 $3.88 $3.10 Y  Material Info Notify Me Purchase
Price Table Help

The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Analog Devices, Inc. sales office or authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.


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