TUSB8040: TUSB8040 Design Guide

Pavaman Panchamukhi

Part Number: TUSB8040
Other Parts Discussed in Thread: TPS2066C

Hi ,

I have read the application TUSB8040 Design Guide and application note mentions to use a Ferrite Bead on VBUS USB power line.

the Ferrite bead used is BLM18PG221SN1D with 220 ohms at 100MHz. Could you pls guide why did we select 100Mhz freq range instead of Selecting the Radiated EMI and Conducted EMI freq range.

Currently we are using USB 3.0 with Speed of 2.5GHz and would the Ferrite bead selected have any bad impact like lossy signals at operating USB Freq ?

Kindly suggest what other ferrite bead specification i should look for USB 3.0 application.

Regards

Pavaman P

over 2 years ago

0 JMMN over 2 years ago

TI__Guru 60865 points

Hello Pavaman,

We selected a ferrite bead to help isolate the VBUS line and suppress power noise, this same ferrite bead should not be used on the USB data lines. There are several vendors that make ferrite beads specifically for the USB 2.0 and USB 3.x data lines. TI does not have a specific recommendation other than to look for ferrite beads that are intended for USB 2.0 or 3.x operation.

Please let me know which device you are using, TUSB8040 is not recommended for new designs.

Regards,

JMMNB

0 Pavaman Panchamukhi over 2 years ago in reply to JMMN

Prodigy 30 points

I am using USB HUB USB2514 and TPS2066C is connected to Type C connector as Current limiter to limit the current to USB 3.0 device.

On, VBUS power line we intend to use FB and from TUSB application note there is recommendation to use FB. What could be the parameters which we need to look in Ferrite Bead for USB 3.0 application

0 JMMN over 2 years ago in reply to Pavaman Panchamukhi

TI__Guru 60865 points

Hello Pavaman,

The requirements for the VBUS ferrite bead do not need to vary between USB 2.0 and USB 3.0.

Regards,

JMMN

0 Pavaman Panchamukhi over 2 years ago in reply to JMMN

Prodigy 30 points

What all parameters need to check for selection of FB.

0 Chuck Branch over 2 years ago in reply to Pavaman Panchamukhi

TI__Mastermind 26910 points

I apologize. This has bounced around the forum a bit. I am sending it to the right person now.

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TUSB8040: TUSB8040 Design Guide