16 bit diff mode maximum voltage

Status
Not open for further replies.

Iwilsonp

Member
The datasheet says that in 16 bit differential operation, the maximum input voltage is 31/32 of AREF. What happens if I go above this? Does it simply not register, or does my Teensy 3.2 explode?

I am measuring an angle with a pot, and while in normal operation I will not go above 31/32*AREF, I want to know how careful I have to be. I also don't really want to scale the voltage with a resistor, as that would reduce my resolution.
 
It depends on how much and how long the input exceeds the manufacturer's limits. Generally, there's some margin. Your application makes a difference, too. If you're learning and you've got spares, you can experiment. If the consequences burning a part are great, then external signal conditioning, current limiting, voltage limiting and redundancy might be used.

I've made a few wiring mistakes over the years and I've yet to measurably damage a Teensy. I say measurably because some events like electrostatic shocks can result in latent faults.
 
Is this for a Teensy ADC? In that case don't expect more than 13 ENOB accuracy. The resolution may be higher but the 3 LSB are unlikely to be meaningful. Particularly for pots since peak ADC performance is predicated on a signal source with less than 8 ohms of resistance. You may be able to compensate via capacitors on the input of the ADC but bottom line is that 16 bits of ADC performance is likely only achievable on a external ADC.
 
You can always use a zener diode to protect from overvoltage

Problem with zeners is they degrade your analog signals. once you get within 1-2V of the zeners rating it starts conducting a fair amount of current, if your measuring from a divider that means the results become less accurate the closer you get to the zeners rating.
 
> 16 bits of ADC performance is likely only achievable on a external ADC.

And even then it can be hard to get. Lots of ways that noise can get added.
 
Status
Not open for further replies.
Back
Top