MSP430F2274-EP: Is the max ADC input voltage limited by VCC or VREF+?

adevries

Part Number: MSP430F2274-EP

Hello,

On the MSP430F2274-EP, is the maximum recommended ADC input voltage limited by VCC or by VREF+? For example, if I'm using the internal 2.5V reference as VREF+, VCC = 3.3V, and I try to measure a 3.1V analog signal, will that exceed the recommended analog input voltage range? Will damage occur to the device? and what value should I expect the ADC to convert it to?

Thanks

over 3 years ago

0 Keith Barkley over 3 years ago

Guru 35580 points

There are two things to consider here, ADC accuracy and damage. If you apply a higher voltage than Vref, the ADC will return the maximum number of counts, but not be damaged. Damage occurs if you apply a few tenths of a volt more than Vcc.

0 adevries over 3 years ago in reply to Keith Barkley

Intellectual 945 points

Hi Keith,

Thanks for the quick reply. That was going to be my guess as well, but I wanted to verify that idea before implementing it. Also, do you know of any resources that would help me calculate the total error I can expect from ADC measurements? I'm sure it's a function of the voltage reference error + ADC error + other sources of error, but I don't know the proper way to combine the listed error data to get what I'm looking for.

Thanks

0 Johnson He over 3 years ago in reply to adevries

TI__Mastermind 28286 points

Hi Adevries,

For Pin max tolerate voltage and ADC input range as your reference:

Best Regards

Johnson

0 adevries over 3 years ago in reply to Johnson He

Intellectual 945 points

Hi Johnson,

Thanks for the information. So if the analog input voltage range is above VR+ but below VCC, no damage will occur, but the ADC conversion result will not be valid, right? Would the ADC conversion result just be the maximum value? e.g. 0x03FF for ADC10 modules?

Thanks

0 Johnson He over 3 years ago in reply to adevries

TI__Mastermind 28286 points

Hi Adevries,

Yeah, Right!

Best Regards

Johnson

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MSP430F2274-EP: Is the max ADC input voltage limited by VCC or VREF+?