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TMP235: Is it enough to select an ADC of 12bit resolution such as the inner ADC of MSP430FR2153 to fulfill the resolution demands of TMP235?

Part Number: TMP235
Other Parts Discussed in Thread: MSP430F5528, MSP430FR2153

(1) TMP235 has two accuracy levels,

– A2 Level: ±0.5°C (Typical)

– A4 Level: ±1°C (Typical)

(2) • Positive Slope Sensor Gain, Offset (Typical): – 10 mV/°C, 500 mV at 0°C (TMP235).

And I am selecing an ADC to measure the voltage to get the tempearature. I would like to use the inner  ADC of  MSP430 as I have seen the  TMP23xEVM uses MSP430F5528 as the ADC.

And I want to get  1°C resolution whatever.

(1) Is it enough to  select an ADC of 12bit resolution  such as the inner ADC of  MSP430FR2153 to fulfill the resolution  demands of TMP235?

(2) Do I need extra an OP to finish my design?

Thank you!

  • Hello Forum user

    The ability to measure accurately depends on the resolution of the ADC step per LSB. With a 12-bit ADC and 2.5V as the reference source, the step size of the ADC is 0.610 mV per LSB. This means that for measuring 1 C change, the number of LSBs that will change is 16 LSBs. That is sufficient for most purpose to be able to sense the 1 C chnage. At the same time, you need to ensure that the effective number of bits from the ADC, i.e noise free bits is also less than 16.