SLASFM1A June 2025 – December 2025 AFE10004-EP
PRODUCTION DATA
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.
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.