TUSB214: TUSB214 SCH review

Lisa Xu

Intellectual 505 points

Part Number: TUSB214

Dear TI Team:

we have 2 * TUSB214 in our design for USB 2.0 signal, pls help review the sch attached,

Thanks

Best Regards

Lisa

USB conditional.pdf

over 1 year ago

0 Ryan Kitto over 1 year ago

TI__Mastermind 37500 points

Hi Lisa,

Here are my schematic reviews, please review the comments and let me know if there are any questions: TUSB214_Foxconn_NearCPU_SchemReview.pdf TUSB214_Foxconn_NearConnector_SchemReview.pdf .

Please let me know if you have any other questions.

Thanks,

Ryan

0 Lisa Xu over 1 year ago in reply to Ryan Kitto

Intellectual 505 points

Hi Ryan:

Thanks for your review and feedback.and there is one item need you help.

1. Is RSTN being driven for both high and low, or just driven high when needed? If only being driven high when needed, should be okay.

==>we paln to have both high and low application for RSTN pin. So the sch need revise or not?

Best Regards

Lisa

+1 Ryan Kitto over 1 year ago in reply to Lisa Xu

TI__Mastermind 37500 points

Hi Lisa,

If the RSTN pin is being driven externally, you do not need to use an external capacitor. You only need to ensure that the RSTN pin is held low until the supply voltage reaches the specified minimum requirements of voltage.

If you want, you can leave the capacitor pulling down to ground. It should still be able to delay the power-on timing.

Please let me know if you have any other questions.

Thanks,

Ryan

+1 Lisa Xu over 1 year ago in reply to Ryan Kitto

Intellectual 505 points

Hi Ryan:

Thanks for your highlight, So Can I still keep the 1K ohm to gound mounted and NC the cap?

because I cannot guarantee the initial status of CPLD pin that controls this RSTN pin, So keep 1K to gound for RSTN pin to guarantee initial default status to be low.

Best Regards

Lisa

+1 Nicholaus_Malone over 1 year ago in reply to Lisa Xu

TI__Mastermind 27925 points

Hi Lisa,

A capacitor is recommended instead of a resistor.

Choose a capacitor value that has a ramp-time described in chapter 9 of the datasheet to make sure that RSTN is 5x longer than the VCC ramp-up time. [Ramp Time x 5] ÷ [500 kΩ]. So, even if CPLD is high at power-up, the device won't be enabled until 100us after Vcc is stable.

Regards,

Nicholaus

0 Lisa Xu over 1 year ago in reply to Nicholaus_Malone

Intellectual 505 points

Hi Nicholaus:

Thanks for your feedback and I will delete the 1K pull down resistor.

Best Regards

Lisa

0 Lisa Xu over 1 year ago in reply to Nicholaus_Malone

Intellectual 505 points

Hi Nicholaus:

For power supply VCC design, whether need a bead between main power VCC_3V3 and TUSB214 VCC?

Best Regards

Lisa

+1 Ryan Kitto over 1 year ago in reply to Lisa Xu

TI__Mastermind 37500 points

Hi Lisa,

For the TUSB214, a ferrite bead should not be required. If there seems to be a large amount of noise in the power supply, it may be necessary, but as is, we do not have any requirements for a bead.

Please let me know if you have any other questions.

Thanks,

Ryan

+1 Lisa Xu over 1 year ago in reply to Ryan Kitto

Intellectual 505 points

Thanks Ryan

+1 Ryan Kitto over 1 year ago in reply to Lisa Xu

TI__Mastermind 37500 points

Hi Lisa,

No Problem. Please let me know if you have any other questions.

Thanks,

Ryan

0 Lisa Xu over 1 year ago in reply to Ryan Kitto

Intellectual 505 points

Hi Ryan

No other questions thanks a lot!

Interface

Interface forum

TUSB214: TUSB214 SCH review