MSP430F2013: Sigma Delta ADC speed

Hello Ali,

Thanks for posting your question to E2E. Sigma Delta and SAR ADCs are used for different reasons. Generally, Sigma Delta ADCs offer high resolution but slower sampling rates compared to SAR ADCs. Take a look at the following (dated but still relevant) resource discussing MSP430 ADCs.

Ali Anwar said:

What is the sample speed of the MSP430F2012 16-bit Sigma Delta ADC? The SAR ADC supports 200 ksps, but the sample speed is not specified for the Sigma Delta ADC.

First, the MSP430F2012 does not have a Sigma Delta ADC, but the MSP430F2013 does.

For a Sigma Delta ADC, the sampling frequency (Fs) can be calculated by dividing the modulation frequency (Fm) by the oversampling rate (OSR).

Fs = Fm / OSR

According to the MSP430x2xx Family User's Guide, the MSP430F2013 features an OSR range from 32 to 1024. According to page 43 in the datasheet, the max modulation frequency is 1.1MHz. Thus, the max sampling rate for this device is 34.375ksps.

Ali Anwar said:

Also, what is the sample speed of the MSP430I20xx 24-bit Sigma Delta ADC?

Using the same approach as above, the max sampling rate for this device is 32ksps.

Finally, keep in mind that with Sigma Delta ADCs lower OSRs (faster sampling rates) result in lower resolutions.

Regards,

James

MSP Customer Applications