Board Layout Mitigation Strategies for Thermally Coupled Internal Reference Voltage Drift
Isothermal component placement, substrate trenching, and balanced copper pours mitigate internal reference voltage drift caused by thermal board stress.
Reference Lookup Table LUT
Data Map
Non-linear sensor outputs can be linearized efficiently using pre-calculated values stored in the non-volatile memory of a microprocessor. This digital array is called a reference lookup table LUT, which correlates raw sensor outputs directly to corrected physical values. The method applies to processors that lack the computing power to execute complex analytical equations in real time.
Interpolation Method
Processing algorithms retrieve the raw digit value from the sensor and locate the closest corresponding points within the array. It then applies linear interpolation to calculate the precise physical value between these points, a process that requires minimal clock cycles. This approach keeps the processing loop short and predictable, which is essential for real-time control applications.
The accuracy of the result depends on the number of points stored in the table.
Memory Constraint
Large tables provide greater accuracy but consume more memory on the microchip. Developers must balance the spacing of the data points against the storage limit of the processor. If the table is too small, the interpolation errors can exceed the accuracy of the sensor itself.
Calibration Step
Production labs populate these tables by placing each sensor in a series of controlled reference environments and recording the output. This data is converted into a binary file and programmed into the device memory before shipping. A sensor that does not match the stored reference lookup table LUT values during final testing is rejected or reprogrammed.
This step ensures that each device is individually matched to its output profile.