TPS65981: Port Data Multiplexer for USB hi-speed benefit

Mario Michel95

Part Number: TPS65981
Other Parts Discussed in Thread: TS5USBC402EVM

Hello TI Team,

we are using the TPS65981 with some products and now we're discussing a redesign. Next to the PD features we just use USB2.0 hi-speed. The Type-C receptacle D+/D- (top/bottom) lines are connected to the TPS65981 multiplexer as described in the datasheet. Now, with the re-design, we plan to add an alternative Type-C receptacle so we can switch between the two possible receptacles (in our case switching from front- to backside of the device housing). The selection will be done during manufacturing and will be fixed from then on (so, no switching during operation).

Can you explain why there is an USB hi-speed MUX in the TPS65981? Isn't it possible to connect the corresponding top and bottom hi-speed lines (D+/D-) directly at the receptacle and route just one pair to the peripherals (in our case a µC) ...at least for our particular application? I've seen that in other designs, e.g. the TS5USBC402EVM.

Thanks and

Best Regards

Mario

over 4 years ago

0 Adam Mc Gaffin over 4 years ago

TI__Mastermind 28350 points

Hello Mario,

Some application use all 4 lanes, not just 2, so a MUX is required to pass the signals correctly

0 Mario Michel95 over 4 years ago in reply to Adam Mc Gaffin

Prodigy 160 points

Hello Adam,

so I can leave the C_USB_* pins disconnected if bypassing the D+/D- lines? If so, do you recommend pull-up or -down resistors here?

Thanks and Regards

Mario

0 Adam Mc Gaffin over 4 years ago in reply to Mario Michel95

TI__Mastermind 28350 points

If you are not using the D+/D- lines in your system at all then yes, you can leave these pins disconnected. However, if you are using USB2 data in your system you need to use the built in MUX to help pass through the correct USB2 connections depending on the orientation of the Type-C connector

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TPS65981: Port Data Multiplexer for USB hi-speed benefit