You are here

Analog inputs | Cypress Semiconductor

Analog inputs

Summary: 2 Replies, Latest post by danaaknight on 18 Jul 2012 07:33 PM PDT
Verified Answers: 0
Last post
Log in to post new comments.
jgmDESIGNS's picture
20 posts

Hello all,

I am working with a PSoc3 chip.  First time using the PSoC, and I am wondering can I send a sine wave into an analog input to a low pass filter inside the PSoC?  Since the PSoC is running at 3.3vdc the sine wave will canter on 1.5vdc and swing approximately 1vp/p.


Is this allowable or is the analog input DC level only?  Also, if the answer is YES that I can send a sinewave into the device, can I take th eoutput of my PWM, and send it through an internal integrator and output a sine wave?


Thank you in advance.



user_78878863's picture
2551 posts

Yes, you can send in a sine wave to the PSoC3 - its inputs are perfectly capable to handle AC inputs (up to several MHz, depending on the voltage levels). But you cannot go below ground or above Vdda with your signal - but your proposed signal would be fine even with 3.3V Vdda.

I think there is no internal integrator, but you should be able to build one by yourself using the inernal OpAmps and some external capacitors / resistors. Or you go experimental and digitize the signal and feed it into the digital filter...

user_14586677's picture
7646 posts

Always examine data sheets to see if you are working withg R-R Inputs

and outputs, otherwise limited CM range will limit pk-pk swings.


To offset signals into PSOC you can ac couple to a simple divider that

supplies the offset to the input. Or you can use the following which eliminates

couplig cap, just uses two R's -


Excel spreadsheet to calc values attached.


For PWM integrator, a simple RC network offten surfices. This ap note discusses tradeoff of

settling time and ripple in the RC filter.



Regards, Dana.

Log in to post new comments.