PCA9306: Application Usage Consult

Hi Stanley,

What does the 20M stand for? Is this a distance rating or a speed rating? The PCA9306 can be used for MDIO applications however, when you are level translating this can lead to some issues with the device. The biggest issue is going to be balancing your VOLs with the speed of your signal. For higher speed signals you will have to use stronger pull ups so that your rise times are adequate. However, a smaller resistor will lead to a higher VOL. You have to make sure that your VOL is low enough for the other device to accept it as a logic low.

I also recommend reading through an E2E thread written by another application engineer Jonathan Nerger. This thread goes over some other aspects that you have to keep in consideration when using the PCA9306 for an MDIO application.

What speed are you running your MDIO signal at? The lower the speed the better.

Best,

Chris

Hi Chris,

Thanks for helps. It's speed rating, the 20M means 20MHz here. I see below D/S notes our part can support >100MHz application. Is that okay for using this device in 20MHz MDC/MDIO application. Thanks.

Best,

Stanley

Yes,

You can definitely go for it Stanley, but like I said when it comes to pull up resistors you may see very large VOLs in order to drive the signal at this speed. Hopefully your other device can accept large VOLs. I would definitely test out this set up and if you need an EVM let me know.

Best,

Chris