Hello,
I am using the S32K388 for my application. I would like to use the ADC of the chip to measure analog voltages. I supply the VDD_HV_A and VDD_HV_B with 3.3V, and usually I use a 2.5V high precision voltage reference for the reference voltage of ADC (when I use dedicated ADCs ICs). If possible I would like to still use the same voltage reference.
When looking at the datasheet for the S32K388, I see that the VREFH needs to be between 2.97V and 5.5V (p20) and always VREFH <= VDD_HV_A.
I also see that accuracy figures given on table 38 are valid for VDD_HV_A - 1.5V >= VREHF >= VDD_HV_A + 0.1V
Do you confirm that I cannot use the 2.5V reference voltage for this purpose and that I need to find a reference of at least 3.0V for my application? Or with VREFH = 2.5V and VDD_HV = 3.3V I will be fine?
Best regards,
Jules
Hi,
that would be out of specification, as VREFH is limited to a minimum of 2.97 V according to the datasheet.
As you wrote you need to find a reference of at least that specified minimum.
Seems Note [5] in the datasheet will be valid for VDD_HV_A = 5V.
BR, Petr
VREFH ADC high reference voltage [1][6] Min2.97 Typical3.3 or 5.0 Max5.5V
VREFL ADC low reference voltage [1] -0.1 0 0.1V
If you put 2.5V for VREFH ADC high reference voltage, that mean the value is out of spec between 2.97V and 5.5V. The ADC function will fail