TS3A5018: why the behavior of COM3&COM4 behavior is different with COM1&COM2?

Hey Helen,

The channels shouldn't behave different than the rest. Since you've shorted COM3 and COM4 together it does make sense for those two to show the same results. I would suspect it's something in the timing with the SIO pin of the QSPI peripheral (SPI1 and SPI2 in the schematic). If you have the flexibility to do so, can you disconnect the COM3 and COM4 from the QSPI and probe the output. You can just place a dummy load that is close to the QSPI load.
Are there any internal pullups/down or some note on the timing specs of the SPI1 and SPI2 devices that may support different timing specs for CS and SCK vs SIO?

Thanks,
Rami

Hi Rami,

COM3 & COM4 not shorted together. Its use the bus net to wire the schematic.

QSPI portion is as below:

I've tried to disconnect the COM3 and COM4 from the QSPI.

It still has delay here. 

BR,

Helen

Hey Helen,

Oh that makes a lot more sense to me. Thanks for clearing that up.

There isn't anything that immediately stands out to me that could be causing this. Is this a prevalent problem across multiple chips? Have you tried ABA swapping to see if the issue follows that particular chip?

Thanks,
Rami

Hi Rami,

I've tried the ABA swapping. It would be delay,too.

Does it cause from 2 MUX series? I'm not sure.

BR,

Helen