LTE SC206E Smart Module acting as USB host and device

Dear Team,

We have a requirement such that [SC206E] should act as a device when USB cable is connected to J12 for programming ,otherwise it acts as a host. For this purpose we have implemented the circuit as shown here. Let me give a brief introduction about how this circuit works.

The usb datalines coming from SC206E is connected to USB mux( U67) the one of the output (HSD2+ and HSD2-) of this mux is connected To usb connector (J12) and the other output (HSD1+ and HSD1-). is connected to the USB lines of SMA5D27.For device mode CC1 and CC2 of the SC206E needs to be pulled up with 56K And for host mode CC1 and CC2 must be pulled down with 5.1K.For this purpose also another USB MUX (U68) is used. The default mode of SC206E is USB host.The select lines of the mux’s are connected to GND

Let me explain how the device mode works.For device mode,You can see that the select lines(VBUS_USB_CONN) for both the MUX’s are same and they are coming from the USB connector.When USB cable is connected VBUS_USB_CONN will be high and this will make the SEL lines Of MUX’s high and SC206E act as USB device.

May I know your thoughts about this circuit.Will the impedance of FSUSB42MUX cause any issues.Do I need to change the pull up and pull down according to the impedance of MUX.


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