Evaluation of Integrated AD Converter under Varying Temperature Conditions

Analog to digital converters (ADCs) are essential components in embedded systems, where analog signals must be translated into digital representations. Their performance can be significantly affected by ambient temperature, which may lead to practical challenges in precision critical applications. This study, conducted at Saab Dynamics in Karlskoga, evaluates two types of ADCs, the internal 12 and 16-bit converters of the STM32H757 microcontroller, and the external 12-bit AD7890-10. Measurements were performed at room temperature, +65°C and -35°C to analyze how temperature variations affects measurement accuracy and linearity. The results show that the STM32:s internal ADCs exhibited larger and more nonlinear deviations, particularly close to the input range limits. The AD7890 also showed temperature related errors, but these were smaller in magnitude and more linear. The finding suggests that external ADCs may be preferable in thermally demanding environments where high measurement accuracy is required.