Product category:
Sensors and Data Acquisition
News Release from: Melexis | Subject: MLX90614
Edited by the Electronicstalk Editorial
Team on 18 September 2006
Infra-red sensor takes signal
conditioning onboard
IR sensor helps OEMs to integrate noncontact temperature measurement in car air conditioning, room heaters, home appliances, handhelds and medical equipment.
Temperature is the most often measured physical parameter However, remote noncontact temperature measurement has previously been complicated and expensive due to the complex signal treatment and calibration involved
This article was originally published on Electronicstalk on 17 Oct 2003 at 8.00am (UK)
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This small and cost effective noncontact thermometer delivers a fully calibrated, digital temperature reading of a remote object.
It achieves this feat by integrating an infra-red sensor and a custom signal conditioning chip in one TO-can package.
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Due to the built-in intelligence, high accuracy and wide temperature operating range of the MLX90614, OEM manufacturers can easily integrate noncontact temperature measurement in car air conditioning, room heaters, home appliances, handhelds and medical equipment.
The sensing element in the MLX90614 is an automotive grade silicon chip with a thin, micromachined membrane heated by the infra-red radiation of a distant object.
This heating is detected by on chip thermocouples.
The custom built signal conditioning chip amplifies and digitises the minute thermocouple voltage and calculates the object temperature using factory set calibration parameters stored in the EEPROM memory of the chip.
The digital output temperature is fully linearised and compensated for ambient temperature.
The sensor transmits the result to the user's application either over an SMBus or by a continuous PWM signal.
The whole thermometer system is enclosed in a TO-can.
To the OEM manufacturer these properties offer the advantage of easy integration of the sensor on the application's PCB without the need for expensive external components.
This self contained system eliminates the design challenges of very small voltage signals, environmental effects and electromagnetic compatibility which otherwise make infra-red temperature measurements difficult and cumbersome.
The high level of integration makes the MLX90614 very cost effective compared with other infra-red solutions currently on the market.
The MLX90614 applies advanced low noise amplifiers, a 17bit ADC, and powerful DSP unit in its signal conditioning chip allowing a wide operating temperature range of -40 to +125C and an extended object temperature range of -70 to +380C while maintaining a temperature resolution of 0.01C.
The standard MLX90614 has a high absolute accuracy of +/-0.5C in the object temperature range of 0 to +50C and +/-1C outside that range.
These qualities make the sensor suitable off the shelf for a wide range of uses.
A version with the increased accuracy needed for medical applications is also available on request.
There are two variants of the MLX90614 available, one for 3V and the other for 5V power supply operation.
With its less then 1mA current consumption, the 3V option is targeted at handheld, battery operated devices.
For this reason the sensor also has a power saving "sleep" mode in which the current consumption can be as low as 2uA.
For power directly supplied from a 12V car battery, the 5V model contains electronics to operate it at higher voltage with a few external components.
Victor Kassovski, Infrared Business Unit Manager at Melexis, comments: "We have condensed Melexis' decade long experience with noncontact thermometer manufacturing in the MLX90614 and made sure that this thermometer will be an easy to use, cost effective solution for OEM manufacturers in a wide range of applications".
The MLX90614 is qualified in accordance to AECQ100 and is RoHS compatible.
It can be soldered up to 260C according to JEDEC 020C.
Samples of the integrated thermometer are available now and production quantities can be ordered with a lead time of 20 weeks.
Estimated pricing for the MLX90614 will be Eur 4.55 in 1000-piece quantities.
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