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STM32H743 ADC Common mode input  voltage specification

Question asked by Uwe Bonnes on Oct 17, 2017

Hello,

 

ds12110 rev 2 for the STM32H743 tells in table 84 for V(CMIV) a low limit of  VREF/2-10% and a high limit of  VREF/2 +10%.  This would mean e.g. with Vref = 3 Volt that a measurement with ADCIN+ pin at 0.5 Volt and ADCIN- pin at 1 Volt would be out of specified range. In the example V(CMIV) = (ADCIN+ + ADCIN-) / 2 = 0.75 Volt is far off the 10 % range around VREF/2 = 1.5 Volt. Usability of the ADC in differental mode would be substantial hampered.

 

Do I missunderstand V(CMIV)? Or is the datasheet wrong? Or does the H7 ADC really have that hard requirements for V(CMIV)?

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