TXS0206A: Are there any recommendations for how close the TXS0206A should be to the SDCARD connector?

Lauren Mayfield

Part Number: TXS0206A
Other Parts Discussed in Thread: TXS02612

Are there any recommendations for how close the TXS0206A should be to the SDCARD connector? I'm asking for my customer, they saw when using a similar non-TI part, they found it to be quite sensitive to additional load capacitance, and they have seen intermittent failures as a result. They think this is something that affects the auto direction detect circuit in these types of parts. They want to make sure that the TI part doesn't have the same issue.

5 months ago

0 Jack Guan 5 months ago

TI__Guru 59551 points

Hi Lauren,

The sensitivity to capacitive load stems from the one-shot architecture that this device uses on the directional data lines (DATx). To ensure proper functioning of the one-shots, it is recommended to keep the capacitive load (board parasitics, trace lengths, total lumped cap.) to a minimum, which allows the output signal to drive up to VCC. If excessive loading is used at the outputs, the one-shots can time out prematurely and result in the remainder of the output logic high signal unable to achieve desired levels.

Section 3 of this app note covers this point further: https://www.ti.com/lit/an/scea043/scea043.pdf?ts=1770319038428&ref_url=https%253A%252F%252Fwww.google.com%252F

Regards,

Jack

0 Lauren Mayfield 5 months ago in reply to Jack Guan

TI__Expert 8175 points

Hey Jack, thanks for the response but my question is still unanswered, I was asking about distance/length recommendations between TXS0206A and the SD card connector.

Are you suggesting there are no recommendations for how far apart the devices are, just in the total capacitive load (which includes the trace lengths)?

0 Jack Guan 5 months ago in reply to Lauren Mayfield

TI__Guru 59551 points

Hi Lauren,

Yes you are correct- there isn't a specific trace length that this device was designed up for. It is more so the total capacitive load that is of concern (about 70pF of Cload).

Customer may refer to this EVM for further evaulation: https://www.ti.com/tool/TXS0206AEVM

e2e.ti.com/.../faq-what-is-the-maximum-trace-length-that-a-logic-device-can-drive

Regards,

Jack

0 Lauren Mayfield 5 months ago in reply to Jack Guan

TI__Expert 8175 points

Thanks Jack, another part they're considering is TXS02612. What is the total cap load maximum for that part?

0 Jack Guan 5 months ago in reply to Lauren Mayfield

TI__Guru 59551 points

Hi Lauren,

It would be similar, and the reasoning is due to the one-shots architecture found in the channels driving the bidirectional DATx lines.

Regards,

Jack

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TXS0206A: Are there any recommendations for how close the TXS0206A should be to the SDCARD connector?