Kinetis M Series (KM1x and KM3x) 24 bit ADC Performance

[bvenus]

The current datasheet for the KM series only outlines the 16 bit ADC specifications.

What is the 24 bit ADC specifications, specifically SINAD and ENOB?

[apanecatl · Accepted solution]

You can find the 24-bit specs in the following chapter: 6.4.4.2 ΣΔ ADC Standalone specifications of the devices datasheet, the document can be downloaded from the following link:

http://cache.freescale.com/files/32bit/doc/data_sheet/MKMxxZxxACxx5.pdf

[rabbitz]

If the MCU run at 50Mhz clock and sampling with 24 bit resolution, do you know how fast can it sampling?

[MarMi]

The SD ADC conversion rate depends on the modulator clock (fmclk) and selected oversampling ratio (OSR). Datasheet parameters of the SD ADC (for normal operation) are specified for fmclk=6.144MHz and OSR=2048, where such configuration results in 3 ksps output sample. You can go down with OSR to 64, which will increase output sample rate to 96 ksps still providing 24-bit result but with lesser noise free bits (~ -2.8 bits).