High accuracy ±0.1°C digital temperature sensor

MMS Electronics improves temperature measurement accuracy with the Smartec SMT172 digital temperature sensor. The SMT172 sensor provides clinical-grade temperature measurement accuracy (±0.1°C) with fast response time to temperature changes. The SMT172 is a digital ultra-low power, factory calibrated, high accuracy temperature sensor with pulse width modulated output signal. PWM output sensors have high noise immunity and high reference accuracy. The sensors are easy to interface and multiplex. The SMT172 duty cycle output is proportional to the measured temperature. Inaccuracy of the T018 package sensor is ±0.1 ºC between -20ºC to 60ºC and 0.4ºC to -35ºC and +130ºC.Max temperature that can be measured with the sensor is +130ºC. Designed for supply voltage 3V, 3.3V and 5V with a voltage range from 2.7V to 5.5V.  This is the most energy efficient temperature sensor in the world with an average current of < 60uA or 220nA based on 1 measurement per second. The ultralow power consumption of the sensor minimises the self-heating effect.

Application are found in wearables, scientific, environmental, medical and industrial measurements.

How is it done:

The SMT172 is designed using the most recent advances in silicon temperature sensing, sophisticated IC design techniques are applied with high-precision calibration methods. The pulse width modulated output is proportional to the measured temperature value. Smartec recommends to measure 8 consecutive pulses or multiples of 8. There may be a variation between each pulse but the average is very precise and stable. Then a simple calculation of the duty cycle returns the sensor temperature. Only one input on a microprocessor is required to connect to the SMT172 sensor. No analogue circuits or analogue to digital converter is required, reducing design complexity, power consumption and cost.


The Smartec SMT172 is available in TO18, TO92, TO220, SOT223, SOIC, HEC, naked DIE and robust stainless steel probes. The wide range of packages allows the designer to pick a sensor suited to the application. For example the SMT172-SOIC can be used on a PCB to protect nearby component from overheating. MMS Electronics has two probes available with the SMT172 sensor built in. A slim 5mm pointed probe with the SMT172-HEC sensor and a robust stainless steel probe SMT RVS1802 with the most accurate SMT172-18 sensor. Both probes have a 5 meter shielded cable.

For quick development with the temperature sensor MMS Electronics has two evaluation boards with USB interface available. The SMTAS04USBmini can measure 4 temperature sensors and SMTAS08USBmini max. 8 sensors. For applications that require an I²C interface there is a sensor-to-I²C converter board available SMT172TOI2C. This little board also converts the SMT172 sensor output so it can be used as a replacement for the now obsolete SMT160-30 sensor.

MMS Electronics, supplier of display and sensor products is based in Pool-in-Wharfedale, Leeds, The company has established strong relationships with top quality LCD display and sensor manufacturers.

Today, MMS Electronics Ltd is the authorised UK distributor for the 2,000 plus LCD display products of trusted German manufacturer Electronic Assembly GmbH (Display Visions) and also represents many other world class display and sensor manufacturers.

Please contact MMS Electronics Ltd with your sensor or display enquiries.

MMS Electronics Ltd


Tel 01943 877668




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