4 port USB hub in a square inch

Gotta have more USB ports

mitchell.dokken

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Description

I always thought this chip would be really cool if I could get it to work. This is my first attempt, just happened to be less than a square inch. Hopefully it works!

Details

Hopefully this is a full speed USB hub, so it can be used to chain PCM2906 sound cards without degrading performance. If not, well, it'll still work for slower things.

Board sent off to OSHPark september 1st, all components are in hand. Here we go.

Files

FE1.1S-inch.sch first test sch - 388.29 kB - 09/02/2018 at 06:42		Download
FE1.1S-inch.brd first test brd - 73.33 kB - 09/02/2018 at 06:42		Download

Project Logs

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USB hub is live
mitchell.dokken • 09/20/2018 at 02:02 • 0 comments

It works! Nothing much to the design but some capacitor filtering and a specific resistor value. It takes 5 volts and shows up as a High-speed USB device:
usb 1-3.2.4: new high-speed USB device number 47 using xhci_hcd
usb 1-3.2.4: New USB device found, idVendor=1a40, idProduct=0101
usb 1-3.2.4: New USB device strings: Mfr=0, Product=1, SerialNumber=0
usb 1-3.2.4: Product: USB 2.0 Hub
hub 1-3.2.4:1.0: USB hub found
hub 1-3.2.4:1.0: 4 ports detected
So thats cool. I cheaped out on the decoupling capacitors for the crystal, as other designs I'd seen didn't have them. It worked without them, and they're trivial to add. I could shrink this further by getting more aggressive with the pad layout, using one of those 2.5 x 2mm crystals, and 0603 passives.