SBOS876B September 2017 – February 2020 TMP461-SP
PRODUCTION DATA.
The TMP461-SP device allows for a different η-factor value to be used for converting remote channel measurements to temperature. The remote channel uses sequential current excitation to extract a differential VBE voltage measurement to determine the temperature of the remote transistor. Equation 1 shows this voltage and temperature.
The value η in Equation 1 is a characteristic of the particular transistor used for the remote channel. The power-on reset value for the TMP461-SP device is η = 1.008. The value in the η-factor correction register can be used to adjust the effective η-factor according to Equation 2 and Equation 3.
The η-factor correction value must be stored in twos complement format, yielding an effective data range from –128 to 127. The η-factor correction value is written to and read from pointer address 23h. The register power-on reset value is 00h, thus having no effect unless a different value is written to it. The resolution of the η-factor register is 0.000483.
NADJUST | η | ||
---|---|---|---|
BINARY | HEX | DECIMAL | |
0111 1111 | 7F | 127 | 0.950205 |
0000 1010 | 0A | 10 | 1.003195 |
0000 1000 | 08 | 8 | 1.004153 |
0000 0110 | 06 | 6 | 1.005112 |
0000 0100 | 04 | 4 | 1.006073 |
0000 0010 | 02 | 2 | 1.007035 |
0000 0001 | 01 | 1 | 1.007517 |
0000 0000 | 00 | 0 | 1.008 |
1111 1111 | FF | –1 | 1.008483 |
1111 1110 | FE | –2 | 1.008966 |
1111 1100 | FC | –4 | 1.009935 |
1111 1010 | FA | –6 | 1.010905 |
1111 1000 | F8 | –8 | 1.011877 |
1111 0110 | F6 | –10 | 1.012851 |
1000 0000 | 80 | –128 | 1.073829 |