What is the maximum input voltage on ADC analog input pins?
What is the maximum input voltage on ADC analog input pins?
There are basically two rules to follow when deciding max voltage on ADC analog input (AIN) pins:
For example, when having 2/3 prescaling you can expose 2.4V/(2/3)=3.6V to an AIN pin. For not to violate rule 2, VDD should be 3.3V or higher in this case.
These are the maximum voltages that can be exposed to an ADC AIN pins in order for not to damage the ADC, depending on supply voltage and your prescale settings:
VDD 3.6, prescaling 1/1: AIN max 2.4V (rule 1 limitation)
VDD 3.6, prescaling 2/3: AIN max 3.6V (rule 1 limitation)
VDD 3.6, prescaling 1/3: AIN max 3.9V (rule 2 limitation)
VDD 3.3, prescaling 1/1: AIN max 2.4V (rule 1 limitation)
VDD 3.3, prescaling 2/3: AIN max 3.6V (rule 1 and rule 2 limitation)
VDD 3.3, prescaling 1/3: AIN max 3.6V (rule 2 limitation)
VDD 1.8, prescaling 1/1: AIN max 2.1V (rule 2 limitation)
VDD 1.8, prescaling 2/3: AIN max 2.1V (rule 2 limitation)
VDD 1.8, prescaling 1/3: AIN max 2.1V (rule 2 limitation)
There are basically two rules to follow when deciding max voltage on ADC analog input (AIN) pins:
For example, when having 2/3 prescaling you can expose 2.4V/(2/3)=3.6V to an AIN pin. For not to violate rule 2, VDD should be 3.3V or higher in this case.
These are the maximum voltages that can be exposed to an ADC AIN pins in order for not to damage the ADC, depending on supply voltage and your prescale settings:
VDD 3.6, prescaling 1/1: AIN max 2.4V (rule 1 limitation)
VDD 3.6, prescaling 2/3: AIN max 3.6V (rule 1 limitation)
VDD 3.6, prescaling 1/3: AIN max 3.9V (rule 2 limitation)
VDD 3.3, prescaling 1/1: AIN max 2.4V (rule 1 limitation)
VDD 3.3, prescaling 2/3: AIN max 3.6V (rule 1 and rule 2 limitation)
VDD 3.3, prescaling 1/3: AIN max 3.6V (rule 2 limitation)
VDD 1.8, prescaling 1/1: AIN max 2.1V (rule 2 limitation)
VDD 1.8, prescaling 2/3: AIN max 2.1V (rule 2 limitation)
VDD 1.8, prescaling 1/3: AIN max 2.1V (rule 2 limitation)