Internal or External SCLK for SAR ADC

Frank Huang16969

Hi, freinds,

I am just curious about why most of the 12bits serial SAR ADC don't have a internal conversion OSC, but most 16bit+ serial SAR ADC do? Is this for the noise/accuracy purpose or just want to make a easier serial interface (with 16bit SPI, not 22 or 24bit)?

Thanks & B. Regards,

Frank Huang

over 15 years ago

0 Rick Downs - WEBENCH Design Center over 15 years ago

TI__Expert 5515 points

Frank,

That's an interesting observation, but I think there are 12-bit ADCs that have internal oscillators as well. The inclusion of an internal oscillator in any SAR converter is mainly for convenience - it certainly isn't for accuracy, because the internal oscillators are notoriously less stable and accurate than an external oscillator. Having the internal oscillator does make it easier for the external system - no need to synchronize clocks and it may simplify the interface.

0 Frank Huang16969 over 15 years ago in reply to Rick Downs - WEBENCH Design Center

TI__Prodigy 160 points

Rick,

Thanks for your clarify, it really helps.

Frank

Data converters

Data converters forum

Internal or External SCLK for SAR ADC