Tip / Sign in to post questions, reply, level up, and achieve exciting badges. Know more

USB superspeed peripherals

abushuev_490810
Level 1
5 sign-ins First question asked First like given
Level 1

The datasheet for the CYUSB3065 IC has a note as follows:

Note: REFCLK and CLKIN must have either separate clock
inputs or if the same source is used, the clock must be passed
through a buffer with two outputs and then connected to the clock
pins.

 

Is there any way to decrease the cost and the footprint of the solution?

Is it acceptable to connect the REFCLK and CLKIN inputs via 33 Ohm resistors to one clock source?

Thank you in advance!

0 Likes
1 Solution
JayakrishnaT_76
Moderator
Moderator First question asked 1000 replies posted 750 replies posted
Moderator

Hello,

We recommend to follow the Note given in the CX3 datasheet. The same is mentioned in the thread below:

https://community.cypress.com/t5/USB-Superspeed-Peripherals/CYUSB306X-REFCLK-and-CLKIN-inputs/m-p/16...

However, we have also seen many customers driving CLKIN and REFCLK using the same clock source (without using a buffer) without facing any issues. When this approach is followed, the clock source should have sufficient strength for driving both CLKIN and REFCLK pins.

Best Regards,
Jayakrishna

View solution in original post

1 Reply
JayakrishnaT_76
Moderator
Moderator First question asked 1000 replies posted 750 replies posted
Moderator

Hello,

We recommend to follow the Note given in the CX3 datasheet. The same is mentioned in the thread below:

https://community.cypress.com/t5/USB-Superspeed-Peripherals/CYUSB306X-REFCLK-and-CLKIN-inputs/m-p/16...

However, we have also seen many customers driving CLKIN and REFCLK using the same clock source (without using a buffer) without facing any issues. When this approach is followed, the clock source should have sufficient strength for driving both CLKIN and REFCLK pins.

Best Regards,
Jayakrishna