AnsweredAssumed Answered

K64F ADC - Using a 3.3V voltage reference IC as VREFH, with VDDA = 3.3V from a seperate power supply

Question asked by Sean Law on Mar 8, 2016
Latest reply on May 30, 2016 by Stanislav Arendarik

Hi,


In the K64F datasheet, it is specified that:

Max VREFH = VDDA.

(See figure 3.6.1.1)

adc.PNG

In our application, VREFH is connected to an external 3.3V voltage reference IC (LM4120AIM5-3.3), and VDDA is supplied by a separate 3.3V power supply IC (MAX8881EUT33-T). What are the repercussions in situations where VDDA is lower than VREFH(due to the fluctuations in line regulation of both chips)?

Outcomes