TMP275's accuracy

P.A.M

Other Parts Discussed in Thread: TMP275, TMP112

Hello,

I'm working on a temperature application using TMP275. It works pretty well.

In the datasheet, it is said accuracy is +/-0.5°C ( form -20°C to 100°C, V+=3.3V, with a 12bits resolution ).
But I cannot find out this result form the "TEMPERATURE ERROR vs TEMPERATURE" curve ( page 4 ). Where the accuracy seems to be +0.125, -0.200 from -20°C to 100°C.
So I'm confused,....
Do I misunderstand this curve ?

In fact I'm looking for TMP275's accuracy and repeatability from 0°C to 40°C.
And is there any linearity problems ?

Thanks

P.A.M

over 13 years ago

0 Chris Featherstone over 13 years ago

TI__Mastermind 25210 points

Paul,

I am currently looking into this and will get back to you shortly.

0 Chris Featherstone over 13 years ago

TI__Mastermind 25210 points

Paul,

The curve you have referenced shows typically what temperature error will be seen across temperature from any given TMP275 device.

The typical error that can be expected from the TMP275 is +/- 0.0625^oC in the temperature region of -20^oC to 100^oC assuming a supply voltage of 3.3V. The maximum error that can be expected is +/-0.5^oC with the same conditions. The curve of Temperature Error vs Temperature on page 4 of the datasheet is derived from the sampled population shown below this curve. The histogram shows the temperature error at room temperature. This population was used to measure the temperature error across temperature and the collected data was used to plot the curve you are referring to.

We assure that the TMP275 will not have an error greater than 0.5^oC and show what will typically be seen with the curve on page 4.

0 P.A.M over 13 years ago in reply to Chris Featherstone

Prodigy 190 points

Chris,

OK,

thank you.

Munck P.A.

0 Douglas Alden over 12 years ago in reply to Chris Featherstone

Prodigy 90 points

Chris,

There was a Analog Wire blog post from 21 Feb 2010 about the TMP112 that discussed how the accuracy of the TMP112 could be improved by performing a single point calibration at 25C. See:

http://e2e.ti.com/blogs_/b/analogwire/archive/2010/02/21/cool-alternatives-to-thermistor-based-designs.aspx

Is the +/-0.5C maximum error of the TMP275 something that can be improved through a similar calibration to reduce the error and put its accuracy within the bounds of the +/-0.0625C between -20C and 100C shown as derived from the sampled population?

Thanks,

Douglas

0 Chris Featherstone over 12 years ago in reply to Douglas Alden

TI__Mastermind 25210 points

Douglas,

The TMP112 has different slopes in regards to temperature error vs temperature. The calibration method presented in the TMP112 datasheet is specific to the TMP112 and cannot be applied to the TMP275.

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TMP275's accuracy