Dear Sir
Good days,
Sorry for i am not familiar TUSB2036, enclosed file is my customer 2 ports USB HUB circuit, i check the frequency 24MHz input may wrong, may you pls help double confirm if there have other issues?
and i check the datasheet application circuit, datasheet have add SN75240, is this part is necessary?
And may we check what EEPROM should put in data? may we have suggestion data can share with customer?
Hello Chen,
Yes, the clock generation is wrong, The TUSB2046 requires a 6 MHz crystal oscillator from which its internal APLL generates a 48 MHz (refer to Figure 7 in the datasheet).
"and i check the datasheet application circuit, datasheet have add SN75240, is this part is necessary?"
Although it is not required to have additional ESD protection on the USB differential pairs, depending on the application and the amount of ESD sensitive circuits in the design, users may want to implement them.
Another important factor that they should follow is the power-up sequence, It requires a reset pulse of between 100us to 3ms after 3.3-V (Vcc) reaches its 90%. I recommend an external RC circuit. See the figure below.
If custom product ID and vendor ID descriptors are desired you can enable EEPROM interface or you can use the default TI VID / PID.
VID / PID can be requested from the USB-IF on usb.org. It is just a way of identifying the device, they do not affect USB performance.
Regards.
