TMS320F28035: Internal oscillator tolerance (lifetime drift worst-case needed)

abe mathew

Worst case oscillator tolerance is based on temperature and lifetime drift.

Our analysis showed the following: we can reach a tolerance band on the stability of the CPU clock (and hence, the CAN transmission frequency) of +/-1.46% across the temperature range -40C to +105C. Onto that tolerance, we added the errors associated with the ADC offset compensation (adds a further 0.175%). However, we dont have a good understanding of lifetime drift and hence assumed a total estimate of +/-2.5% error band across temperature.

Trying to obtain what manufacturer estimates are for 20 year lifetime drift across temperature for these parts.

over 9 years ago

0 Devin Cottier over 9 years ago

TI__Guru 60865 points

Hi Abe,

Are you using the oscillator compensation routine? Are you using internal or external reference mode?

I don't have the accelerated aging data handy, but if we would have observed 1% aging variation I think we would have been very concerned. I think it's probably safe to assume aging is less than voltage variation( which is specified in the datasheet as 175Hz/mv = about 0.34% across the full voltage range).