MMS Electronics has introduced a new range of digital temperature sensors from Smartec. The SMT172 is an ultra-low power, fully calibrated, high accuracy digital sensor. Using the most recent advances in silicon temperature sensing technology, the SMT172 has applied sophisticated IC design techniques and high-precision calibration methods, to achieve an absolute inaccuracy of 0.1 ºC (mode 1) and less than 0.25ºC (mode2) in the range of -10 ºC to 100 ºC. Full temperature range is -45ºC to 130ºC. The sensor operates with a supply voltage from 2.7 to 5.5V. The typical active current of only 60uA, high speed conversion over 4000 outputs per second (room temperature) and extremely low noise, makes this the most energy efficient temperature sensor in the world. The SMT172 has a pulse width modulated output signal, where the duty cycle is proportional to the measured temperature. The sensor can connect directly to a Micro-processor without an Analog-to-Digital Converter. The SMT172 replaces the SMT160-30.
After production for more than 25 year the SMT160-30 temperature sensor is making way for the SMT172. The SMT172 is fully compatible with the SMT160-30 and offers improved specifications.
- Supply voltage 2.7 to 5.5v ( SMT160-30 was 4.8v to 7.2v )
- Supply current only 50uA @ 2.7v ( SMT160-30 was 160uA to 200 uA )
- Standard accuracy 0.25 ºC (SMT160-30 was 0.7 ºC)
- New SOT223 package possible due to smaller die size
How is it done :
The SMT172 is designed using the most recent advances in silicon temperature sensing technology, the SMT172 has applied sophisticated IC design techniques and high-precision calibration methods. The sensor has a pulse width modulated PWM output signal, where the duty cycle is proportional to the measured temperature value. This makes it possible for the sensor to interface directly to a microprocessor without using an Analogue to Digital converter. Therefor it is an extremely easy way to measure the temperature with this factory calibrated sensor and speed up product development.
The frequency of the output sensor is fixed and only the duty cycle contains the temperature information. A simple calculation returns the sensor temperature. Normal accuracy is 0.25 ºC in the range of -10 ºC to 100 ºC. A higher accuracy can be achieved when a second order conversion is used. An inaccuracy of 0.1 ºC can be reached in the range of -20 ºC to 80 ºC and 0.4 ºC in the range of -45 ºC to 130 ºC with the TO18 packages. For the plastic packages TO92 and TO220 the inaccuracy is 0.25 ºC and 0.8 ºC respectively.
The SMT172 is available in TO18, TO92, TO220, SOT223, SOIC, HEC and DIE. There is also a robust stainless steel probes with 5 meter cable.
MMS Electronics has evaluation boards with serial or USB interface that can measure up to 4 (SMT-AS04) or 8 (SMT-AS08) Smartec sensors and connect with the free Smart logger software.
Advantages of using frequency output sensors:
Frequency output sensor offer have high noise immunity and high reference accuracy over analogue sensors. They offer simple interfacing, integration and can easy be multiplexed. For applications where a serial, I²C or SPI interface is required use the high accurate UFDC-1 frequency transducer. Using the UFDC-1 provides a very accurate time-domain measurement without occupying the microprocessor. More information about the UFDC-1 is available on the MMS Electronics website.
Low power applications such as wearable electronics, wireless sensor networks, wireless temperature monitoring and body temperature measurement. Medical applications, bio-chemical analysis, precision equipment, indoor and outdoor environmental monitoring. Process control, battery charging, consumer goods, electronic circuit protection, temperature monitoring in notebook and desktop computers.
Please contact MMS Electronics Ltd with your display or sensor enquiries. MMS Electronics Ltd is an authorised distributor for Smartec sensors, Excelera frequency transducers and Electronic Assembly Gmbh display products.
Display products include: Dot matrix LCD, TFT, OLED, ePAPER modules, DOG chip-on-glass, eDIP intelligent displays, wireless displays, Windows, Linux and Android OS displays with I2C, serial and USB interface, stylish display bezels, serial and USB interface boards, analogue and resistive touch-screens and keypads.
MMS Electronics Ltd
Tel 01943 877668