Other Parts Discussed in Thread: LMT70, TMP117
The LMT70A seems a very useful device, I am evaluating it as an IceCell 0C reference point replacement for themocouples.
Using the values in : 8.6 Electrical Characteristics Temperature Lookup Table (LUT)
engineers may find the following 4 quartic piecewise-polynomial for converting voltage to temperature :
It consists of 4 quartic polynomials (5 values each), constrained to be continuous in value and gradient at each breakpoint.
The last 2 columns are the breakpoints (voltages) for which each quartic is valid.
| 125.2532032081 | -25.093326337 | -0.2163930501 | 0.0980485104 | -0.0323894142 | 302.785 | 574.06875 |
| 70.19241188 | -29.9908860459 | -0.17680832 | -0.0080389126 | -0.0053856012 | 574.06875 | 891.11625 |
| 15.1587296697 | -24.9915729533 | -0.1455544095 | -0.007279563 | -0.0007347763 | 891.11625 | 1149.00275 |
| -32.3274977901 | -22.4931203736 | -0.1640761645 | -0.0136061522 | -0.0015646034 | 1149.00275 | 1375.219 |
At the quoted table temperature values the following graph shows the output temperature errors as a function of temperature :
So it seems to be better than 1 mK up to 100C.
Using the table voltage for 0C of 1097.987, we get :
1097.987000 0.000079
Hope that this helps,
Dr. Beau Webber
