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PCA9548A - SDA latching to low at power up

Kawai
Guru 19785 points
Other Parts Discussed in Thread: PCA9548A

Team

 

My customer is using PCA9548A, having problem when power up.

Some device's SDA line is latched to Low(GND).

 

I found an PCA9548A Errata on the web.

But, customer has enough T_OFF and T_RISE time, had nothing to do with this errata condition.

 

 

This latch problem was solved by inserting RC filter to /RESET pin, made rise time much slower.

I am wondering if one needs to keep /RESET=LOW or not, until VCC go over POR threshold at powering up.

There is an description that if /RESET pin is not used, /RESET should be pulled up to VCC.

If you follow this description, /RESET pin could be undetermined when VCC go over POR threshold.

 

Does this condition can cause such problem ?

Have you ever heard of this kind of problem ?

 

 

Best Regards,

Kawai