TUSB2077A: 6MHZ clock appears on DN and DP input pins, not working as a hub

Hi Henry:

   I'm working on schematic review btu may delay due to holiday.

Best

brian

Hi Henry:

    Can  you re-send schematic with resistor and capacitor value.

Best

Brian

Thanks, E2E was down during the day . I will review it later today.

Best

Brian

Hi Brian, were you able to review this design to identify the problem

Hi Henry:

1: Is R397 1.5k?

2: are these PD 15Kohm?

3:  no Vbus needed for downstream ports?

4:  did Crystal working with 3.3v clock?

Best

Brian

Hi Brian, I uploaded schematic with component values previously. R397 is 1k5, PD's are all 15K, the devices conneting to this hub are all powered independently.

I dont understand Q4. Crystal working with 3V3 clock. ? 

Oscilloscope shows 6MHz at 0.5V p-p at crystal pins, and 6MHz at 3V p-p on USB hub inputs, but only when USB Hub input is connected to the host USB port.

Hi Henry:

    Crystal output should be 3.3v.

Best

Brian

Thanks Brian, can you suggest any reasons why the xtal output is low. I am using 27pF for C215, C234, with 1K5 for R36 and LFXTAL026900 6MHz XTAL. (HC49_4HSMX series).

Hi:

  Is  R36 1.5k?

  Does crystal meet  ±50 ppm from 0°C to 70°C,  ESR  50 Ω?

Best

Brian

R36 is 1.5K, crystal is ESR 60 Ohms, 50ppm. Do I need to adjust R36 for this crystal