it hadn’t returned ACK when I access 0x33 by IIC. It happened occasionally.
- We have produced thousands of products, but this problem occurs with less than 10 products.
- On the product with the problem, there is about a 40% probability that IIC will not respond.
- When the problem occurred, the other IIC devices were normally but MP5515(0X33) had no response.
What the pull up voltage for both SCL and SDA? It seems <1.8V or ~1.8V in your waveform.
And we observed NA at the 9th clock (SCL logic high).
The pull-up voltage is 1.8V.
Could you have a test with 3.3V on these parts?
The min pull-up voltage in the datasheet is 1.2V. Do you find this issue in other cases in which the pull-up voltage is 1.8V?
I want to learn more about your schematic, such as the pull up resistor. We have specification on the
rise time and fall time of SCL SDA. BTW, can we have a conversation in email?
Yes, Could you leave your email address? I will show you the relevant information.
How about the follow-up feedback from customer?
We used IC batches in 2017, it’s a known problem with IIC hang. New batches are no problem.
Thank you! Noted!