AFE10004RGETEP datasheet(31/159 Pages) TI2

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6.3.4 Look-Up Table (LUT) and Arithmetic-Logic Unit (ALU)

Four independent LUTs are used to create arbitrary transfer functions that map temperature to the DAC[0:3]

analog outputs of the device. In concept, temperature is used as a pointer to a table of discrete values that are

representative of the samples of the desired temperature-dependent function.

To minimize storage requirements, the device LUTs are indexed in 4°C increments. Also, the stored values are

only the increments, or first derivatives (Δ), of the modeled transfer function. The internal ALU reconstructs the

original transfer function by integrating the coefficients stored in the LUTs. The errors caused by the coarseness

of the temperature quantization are significantly reduced through the use of linear interpolation, which is also

implemented in the ALU.

Consider the example in Figure 6-8. The top graph shows the target output versus temperature. VDACx is a

smooth, monotonic function with ideally infinite precision. The LUT stores only the increments, or the rise, within

each 4°C interval.

VDACx

Temperature

VDACx

BASE

BASELINE

4°C

LUT Index

24°C

4°C

Figure 6-8. Transfer Function

To recreate the original transfer function, the series of increments must be summed together and added to the

constant BASE value. BASE represents the constant offset that is lost as a result of differentiation; that is, the

storage of the increments only. This process must also be referenced to the common temperature point. This

reference temperature is referred to as the BASELINE, and is fixed to 24°C.

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AFE10004-EP

SLASFM1A – JUNE 2025 – REVISED DECEMBER 2025

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