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TUSB215-Q1: D1M, D2M and D1P, D2P pins connection method

huamu chen
Prodigy 20 points
Part Number: TUSB215-Q1
Other Parts Discussed in Thread: TUSB217-Q1, TUSB213-Q1

Hi,
For some reasons, we design the circuit of tusb215-q1 as shown in the figure below, that is, the 9th and 10th pins of tusb215-q1 are not connected, and the 5th and 6th pins are respectively connected to DP and DM signal lines.
The reason why we do it this way,Because I confirmed that D1M-D2M and D1P-D2P are physically connected through metal wires inside the tusb215-q1.And in this connection method,We have tested the eye diagram which is also OK.
Can tusb215-q1 be used in this way? And I know that there may be some slight differences between the usage method recommended in the datasheet,but is there a greater risk?
Because our product has been designed, if we modify it now, there will be a lot of certification needs to be repeated, which is more troublesome.So please make a detailed evaluation.
thanks!

When there is tusb215-q1, from the eye diagram results, the compensation has worked.
Here are Near End Eye Measurement Set up With Pre-channel Cable.AC BOOST Level = 3,DC BOOST Level = low(40mV).

Pre-channel Cable = 1m:

Pre-channel Cable = 4m:

We did not test the eye diagram without tusb215-q1.

In fact, we have asked tusb217-q1 about the same question before and received your following reply(TUSB217-Q1: D1M, D2M and D1P, D2P pins connection method):

thanks!

  • 0
    TI__Guru 64326 points

    Hi,

    As mentioned before this is not recommended but maybe workable for this device. Test results (functional and eye diagram) may be different form the typical design. Keep in mind that TUSB215-Q1 and TUSB217-Q1 have some differences. TUSB215-Q1 should not be used when there is another USB BC 1.2 controller on the bus. TUSB215-Q1 has a CDP controller that is always enabled and can interfere with the CDP function. You may want ton consider using TUSB213-Q1 if used tuning would be needed.