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MSP430 with ADC for voltage measurement (0~30V) and resolution up to 4.5 digits for industrial application

Yeon Lim
Prodigy 30 points

Hi,

Are these 2 devices tested for voltage measurement application and the ADC resolution is up to 4.5digits?

http://www.ti.com/apps/docs/viewdevices.tsp?blockDiagramId=6279&blockId=9615&designOptionId=11481&appId=591

Thanks & Regards

  • 0
    Guru 227245 points

    No MSP is capable of surviving input voltages above its supply (3.6V max). To measure higher voltages, you need to break them down with a voltage divider. For different input ranges, either a mechanical switch or an electronic switch is used.

    The resolution depends on input voltage range (after breakdown), used reference and ADC resolution.

    With 12 bit ADC12, you can have a resolution of 4095 steps between 0V and reference voltage (which can be an external reference of 1.4V to VCC, or an internal one of 1.5 or 2.5V)
    How many ‘digits’ these are, depends on the voltage divider (or, in case of small voltage, the amplifier) you use.
    But 4.5 digits means (if you want a real 1 digit resolution) 20.000 different values., Which is impossible with a 12 bit ADC. You need at least 15 bit. And a device with an SD16 or SD24 ADC. (note that for those, the reference voltage and therefore the input range, is +-0,6V or +1.2V)

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