Termination Resistors for Type-C to Legacy Ports – KBA97272

Version: *A

 

Question:

What are the termination resistors required on the configuration channel (CC) line for Type-C to legacy cable and Type-C to legacy adapter assemblies?

 

Answer:

The following table provides details of the termination resistors required on the CC line for various Type-C to legacy cable/adapter designs.

 

 

Design

Termination on CC Line

USB Type-C to USB3.1 Standard Standard-A Cable Assembly

Rp1

USB Type-C to USB2.0 Standard Standard-A Cable Assembly

Rp1

USB Type-C to USB3.1 Standard Standard-B Cable Assembly

Rd2

USB Type-C to USB2.0 Standard-B Cable Assembly

Rd2

USB Type-C to USB2.0 Mini-B Cable Assembly

Rd2

USB Type-C to USB3.1 Micro-B Cable Assembly

Rd2

USB Type-C to USB2.0 Micro-B Cable Assembly

Rd2

USB Type-C to USB 3.1 Standard-A Receptacle Adapter Assembly

Rd2

USB Type-C to USB 2.0 Micro-B Receptacle Adapter Assembly

Rp1

 

 

Notes:

  1. The A5 pin (CC) of the USB Type-C plug should be connected to VBUS through a resistor, Rp. The following figure illustrates the functional model for a legacy host port connected to a UFP. This model has an adapter that presents itself as a host to the UFP. The adapter is either a USB Standard-A legacy plug or a USB Micro-B legacy receptacle on one end and the USB Type-C plug on the other end connected to a UFP. For more information about the functional description and value of Rp, refer to section 4.5.3.2.2 and Table 4-10 of the USB Type-C Specification Revision 1.1. 
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  2. The A5 pin (CC) of the USB Type-C plug should be connected to GND through a resistor, Rd. The following figure illustrates the functional model for a DFP connected to a legacy device port. This model has an adapter present as a UFP to the DFP. The adapter has a USB Type-C plug on one end connected to the DFP, and either a USB Standard-B plug, USB Micro-B plug, USB Mini-B plug, or a USB Standard-A receptacle on the other end. For more information about the functional description and value of Rd, refer to section 4.5.3.2.1 and Table 4-14 of the USB Type-C Specification Revision 1.1.
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