High Precision Temperature Sensor Using MSC121x

The MSC121x is an embedded controller with a high-precision, high-stability temperature sensor, a 24-bit analog-to-digital converter (ADC), and an enhanced 8051 CPU. These circuit functions are the major building blocks for an intelligent temperature sensor. After temperature calibration, the on-chip temperature sensor measurement accuracy can reach -0.1degress Celcius with a resolution of 0.01 degrees Celcius over an operating range of minus 40 degrees Celcius to 85 degrees Celcius. Applications for precision temperature measurements include, but aren’t limited to, thermocouple cold-junction-correction measurement, industrial process control, and system temperature monitoring. The article is introducing about the basically concept and operation of the IC temperature sensor.

These single chip-embedded functions can be used to compose a temperature sensing system for intelligent temperature monitoring, temperature measurements for IPC, or cold junction corrections. Temperature measurement is resulting like providing feedback to other systems though communication peripheral, generate status and/or response to other control via input/output peripherals, provides temperature-logging record with 32KB Flash storage, detecting system temperature drift to calibrate measurement offset and gain accuracy for external analog sources.

The MSC121x has a pair of temperature sensing diodes D1 and D2, as shown in the Figure at above. The differential inputs of the on-chip ADC converter are selected though input multiplexers. When the ADC multiplexer control (SFR ADMUX) is set to FFH, the ADC inputs are connected to the temperature diode outputs. The differential voltage of the diode pair provides a temperature reading.

Source; www.texas-instrument.com