TUSB9261 unused USB3.0 IO termination

Bill Bynum

Hi,

In my application the USB 3.0 super speed IO will never be used, and the application will only be running in a USB 2.0 High Speed configuration.

How should the unused pins be terminated?

USB_SSTXP 43 O SuperSpeed USB transmitter differential pair (positive)

USB_SSTXM 42 O SuperSpeed USB transmitter differential pair (negative)

USB_SSRXP 46 I SuperSpeed USB receiver differential pair (positive)

USB_SSRXM 45 I SuperSpeed USB receiver differential pair (negative)

Thanks,

--Bill

over 13 years ago

0 DHarmon over 13 years ago

TI__Genius 16430 points

Bill,

The SuperSpeed differential pairs can be left floating if not be used.

0 Bill Bynum over 13 years ago in reply to DHarmon

Prodigy 235 points

Hi Dan,

Thanks for the quick reply.

Would it be better to pull them to gnd through 10K resistor?

Just thinking of possible noise/EMI side effects.

--Bill

0 DHarmon over 13 years ago in reply to Bill Bynum

TI__Genius 16430 points

Leaving them floating is exactly like having them connected to a USB 3.0 receptacle and then plugging in a USB 2.0 cable, so there is no need to pull them high or low.

0 Bill Bynum over 13 years ago in reply to DHarmon

Prodigy 235 points

Hi Dan,

Got me there!

Thanks!

--Bill

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TUSB9261 unused USB3.0 IO termination