Temperature sensors increase accuracy in “smallest” linear form factor, says TI
Temperature sensors offering 50 per cent higher accuracy, high sensitivity and single-point calibration have been released by Texas Instruments. The company has added linear thermistors that deliver up to 50 per cent higher accuracy than negative temperature co-efficient (NTC) thermistors to its temperature sensing portfolio. The higher accuracy of TI’s thermistors enables operation closer to the thermal limits of the other components and the overall system, says TI, to help maximise performance and reducing the bill of materials (BoM).
NTC thermistors are attractive because of their low price but they present several challenges, including degraded performance at temperature extremes and complex calibration requirements, which increases design time, explains TI. The TMP6x linear thermistors are available at a similar price yet reduce component count and increasing system performance, claims TI.
The thermistors deliver reliable, highly accurate thermal measurements, particularly at temperatures above 80 degrees C, says the company. This is important for industrial, automotive and consumer applications where precise, real-time temperature readings are fundamental to system performance and protection.
NTC thermistors provide less accurate temperature readings due to their low sensitivity and high resistance tolerance at temperature extremes. To compensate, many engineers calibrate at three points across the temperature range or use multiple thermistors to monitor different temperature ranges. Readings can be still be unreliable and require systems to shut down before reaching their true thermal limit. The linearity and high accuracy of TI’s thermistors enable single-point calibration, to simplify design and maximise system performance.
The TMP6x thermistors offer very low typical drift of 0.5 per cent to improve the reliability of temperature measurements to boost system performance while maintaining safe operation. Engineers can use TI’s thermistor design tool, available online to easily calculate temperature resistance values and kick-start a design with example conversion methods and code.
By eliminating the need for additional linearisation circuitry or redundant NTC thermistors, the thermistors can reduce PCB layout size by at least 33 per cent, compared to NTC thermistors, TI says. They are also claimed to be 1/ 10 the size of similar silicon-based linear thermistors, with a low profile and small package area that enable placement closer to thermal hot spots for faster thermal response and more consistent temperature measurements.
The TMP61, TMP63 and TMP64 are available now through TI and authorised distributors. They are offered in through-hole packaging and surface-mount 0402 and 0603 footprint options. A evaluation board, the TMP6EVM is also available for the TMO61, TMP61-Q1, TMP63, TMP63-Q1 and TMP64 thermistors.
