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USB Hosts Hubs Transceivers

New Contributor

Hello,

can i ask if my circuit is correctly design?

I had realize a cuircuit with the USB2502 chip from microchip and i had many problem with the crystal that didn't oscillate. So i ask you if you find some problem with this in my circuit or with some other chip? The board will be powered by the upstream board using the internal 3.3 LDO.

Thanks

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Moderator
Moderator

Hello,

The ECS-120-20-4 used in our DVK is customized and has a drive level of 600uW. However, you could use the standard ECS-120-20-4 with a series resistance to ensure the wattage is within limits.

Best Regards,

Sananya

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Moderator
Moderator

Hello,

For you circuit design, please check the following-

-It is recommended to connect 10K pull up resistors on the OVR# pins even when the ports are not used.

-Please ensure that the crystal used has the following properties- 12 MHz ± 0.05 percent, Parallel resonant, fundamental mode and 600-μW minimum drive level. Load capacitor value is recommended to be 20 pF.

-Please use a reset circuit that provides a minimum of 10ms delay for the hub.

-It is recommended to use decoupling capacitors on VCC_A, VCC_D pins as per Table 7 in the Application Note on HX2VL hardware guidelines .

Best Regards,
Sananya

New Contributor

Hello Sananya,

can i ask if you have a crystal to suggest? i didn't find crystal with a drive level of 600uW, i have seen in the evaluation board you use a 500uW crystal ECS-120-20-4.

Thanks

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Moderator
Moderator

Hello,

The ECS-120-20-4 used in our DVK is customized and has a drive level of 600uW. However, you could use the standard ECS-120-20-4 with a series resistance to ensure the wattage is within limits.

Best Regards,

Sananya

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New Contributor

Ok thanks,

i will add a resistense for avoid to overdrive the crystal.

Thanks

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