topic Re: PCA9685 drive frequency tolerance details in Other NXP Products

PCA9685 drive frequency tolerance details

__invited__hari — Mon, 02 Oct 2023 21:44:01 GMT

Hello NXP,

We are heavily using PCA9685 in our products. I see that it uses an internal clock of 25MHz to drive LEDs, but no tolerance details available. I configured those channels to output 900kHz but the measured value is about 850kHz and this value varies between ICs. Can you please help us with the tolerance details and also the temperature variation details? This is very important for our characterization study. Please support with those details at the earliest.

Thanks,

Hari

Re: PCA9685 drive frequency tolerance details

TomasVaverka — Tue, 03 Oct 2023 06:23:22 GMT

Hello Hari,

The internal 25MHz oscillator in the PCA9685 is untrimmed and has something like a +/-20% variation.

BR, Tomas

Re: PCA9685 drive frequency tolerance details

__invited__hari — Tue, 03 Oct 2023 16:09:01 GMT

Thanks, Tomas, for the quick turnaround.

Can you please share those details about what leads to that 20% variation? Some temperature graphs or any other drift details, etc...

Re: PCA9685 drive frequency tolerance details

__invited__hari — Tue, 10 Oct 2023 15:03:22 GMT

Hello NXP,

Can someone please respond with the requested details soon?

Thanks,

Hari

Re: PCA9685 drive frequency tolerance details

TomasVaverka — Wed, 11 Oct 2023 08:46:48 GMT

Hello Hari,

The PCA9685 is approximately 15 years old and unfortunately all designers are gone. I do not have access to the information such as temperature graphs or other drift details, sorry about that.

BR, Tomas

Re: PCA9685 drive frequency tolerance details

__invited__hari — Thu, 12 Oct 2023 15:44:29 GMT

Understood. Thank you for the clarification.