E-marker ICs (Type-C cable ID) can be used for active and passive cables. Electronically marked USB Type-C cables support USB Power Delivery Structured VDM Discover Identity command directed to SOP'. This provides a method to determine the characteristics of the cable, e.g. its current carrying capability, its performance, vendor identification, etc.
Under what condition is an E-marker IC required in a Type-C cable?
- E-marker IC is required when the type-C cable supports currents higher than 3A.
- E-marker IC is required when the type-C cable supports Superspeed USB3.1 data transfer.
Although most cables will adopt the single E-marker IC solution, some cable manufacturers may wish to place two ICs, one in each connector, thereby reducing one wire in the cable. Each IC is now powered from the Vconn pin at each cable end. Since only the Source will provide Vconn voltage, only one IC is active at the time. The diagrams below show how to connect E-marker ICs:
Simplified Application Circuits
Read more here for the example measurement results of a cable with Richtek E-Marker IC RT1710.
Examples of applications with USB-C cable ID
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