PCA9685PW/Q900 - Frequency measurement

[gopalakrishna]

In one of application, the Part No : PCA9685PW/Q900 using as a PWM generator and interfaced with processor over i2C lines.

Internal clock is used.

It is observed that, the PWM O/P frequency is not matching with configured values, here is the details,

1. Pre-scale Frequency 24 Hz and measured 29 Hz

2. Pre-scale Frequency 678Hz and measured 690 Hz

3. Pre-scale Frequency 1524 Hz and measured 1553 Hz

Please let me know solution to fix this issue.

[ErikaC]

Hello, 

Please find below the answer from the Application engineer:

The PCA9685 is over ten years old and unfortunately all designers are gone. I can recall about this oscillator is untrimmed, so it is +/-25% variation.

We apologize for any inconvenience this may cause you.