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Analog Devices Press Release - May 26, 2010
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Analog Devices Precision Thermocouple Amplifiers with Integrated Cold Junction Compensation Provide Accurate
Temperature Measurement
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Analog Devices Announces Series of Low-cost Precision Thermocouple Amplifiers.
NORWOOD, Mass.--(BUSINESS WIRE)-- Analog Devices, Inc. (ADI), a world leader in semiconductors for
mixed-signal processing applications and leading supplier of signal conditioning technology, today introduced a
series of low-cost, precision thermocouple amplifiers for K- and J-type thermocouples, which are widely used to
measure temperature in industrial, commercial, and scientific applications.
Thermocouple
systems provide accurate and reliable temperature measurements and control, are cost-effective, and can measure a
wide range of temperatures. However, to achieve good measurement performance cold junction compensation and a high
gain accuracy precision amplifier are required. Analog Devices™
AD8494,
AD8495,
AD8496 and
AD8497 thermocouple amplifiers address this issue by featuring on-chip cold junction compensation that
automatically adjusts the thermocouple output for changes in ambient temperature. This feature greatly simplifies
the design process and reduces system cost relative to similar discrete solutions. For more information, visit
http://www.analog.com/pr/AD8495.
We™re using ADI™s thermocouple amplifiers in designs for ultra-pure heating controllers for industrial
applications, said Bob Woskow, president, Robert Marshall and Associates, an Encino, California-based embedded
microcontroller design and development consultancy. ADI™s amplifiers are smaller, complete with internal cold
junction compensation and thus are quite simple to use with few or no additional parts needed on the printed
circuit board. They will do everything we need a thermocouple amplifier to do.
The four new precision
thermocouple amplifiers each convert the small voltages generated by a thermocouple junction into a 5 mV/°C analog
signal that can easily be read by an ADC (analog-to-digital converter) or microcontroller. The integrated cold
junction compensation ensures accurate measurement over a wide range of ambient temperatures while the high
common-mode rejection (0.1°C/V) allows the AD849x to reject common-mode noise that may be associated with long
lead thermocouples. The AD849x thermocouple amplifiers operate off a wide variety of voltages, from single 2.7-V
to dual ±18-V supplies and are very power efficient, consuming only 180 uA quiescent supply current. In
single-supply operation the amplifiers can directly interface to lower-supply ADCs while higher, dual-supply
voltages can be used for industrial systems that require a wide common mode input range. With a single 5-V supply,
the AD849x amplifiers can cover nearly 1,000-degrees of a thermocouple's temperature range. A reference pin allows
for level shifting of the 0°C output so that negative temperatures can easily be measured, even on a single
supply.
Temperature is the second most measured parameter. Systems using ADI's linear products provide
rugged, repeatable temperature sensing with simplified design, said Steve Sockolov, director, Precision Signal
Conditioning Group, Analog Devices. Integrated cold junction compensation greatly simplifies thermocouple system
design for use in all applications including medical dialysis machines, blood analyzers, process control and
instrumentation.
Thermocouple Amplifier Key Features and Benefits • Integrated
cold junction compensation
• 5-mV/°C output with single-supply operation down to 2.7 V and rail-to-rail output • High-impedance
differential input • Reference pin allows offset adjustment • Wide power-supply range: 2.7 V to ±18 V
• High Gain Accuracy “ 0.1% • Low power: 180 µA quiescent supply current • Low cost: less than
US$1.00, in volume • Lead-free MSOP-8 package
Availability, Pricing and Complementary
Products
Product |
Sample Availability |
Thermocouple Type |
Reference Junction |
Price Each Per 10K |
Packaging |
AD8494 |
NOW |
J-Type |
0°C - 50°C |
$0.98 |
8-lead MSOP |
AD8495 |
NOW |
K-Type |
0°C - 50°C |
$0.98 |
8-lead MSOP |
AD8496 |
NOW |
J-Type |
25°C - 100°C |
$0.98 |
8-lead MSOP |
AD8497 |
NOW |
K-Type |
25°C - 100°C |
$0.98 |
8-lead MSOP |
As part of a signal chain, the AD8494/5/6/7 thermocouple amplifiers work well with ADI™s precision data
converters, such as AD7685, and reference buffer amplifiers, such as ADI™s AD8607.
More
Information and Samples
• For more information:
http://www.analog.com/pr/AD8495
• For data sheet: AD849x Data Sheet • For more amplifier product information: visit
http://www.analog.com/pr/Amplifiers-and-Comparators.
About Analog Devices, Inc.
Innovation, performance, and excellence are the cultural
pillars on which Analog Devices has built one of the longest-standing, highest-growth companies within the
technology sector. Acknowledged industry-wide as the world leader in data-conversion and signal-conditioning
technologies, Analog Devices serves over 60,000 customers, representing virtually all types of electronic
equipment. Celebrating over 40 years as a leading global manufacturer of high-performance integrated circuits for
analog- and digital-signal processing applications, Analog Devices is headquartered in Norwood, Massachusetts,
with design and manufacturing facilities throughout the world. Analog Devices' common stock is listed on the New
York Stock Exchange under the ticker “ADI” and is included in the S&P 500 Index.
http://www.analog.com
Follow ADI on Twitter at
http://www.twitter.com/ADI_News.
Contact
Analog Devices, Inc. Colleen Cronin
781-937-1622
Colleen.cronin@analog.com
Posted 5/26/2010 |
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