USB 3.1 USB TYPE-CTM

1 USB FRONT-PANEL INTERNAL CABLE AND CONNECTOR USB FRONT-PANEL INTERNAL CONNECTOR AND CABLE, REVISION i USB / USB TYPE-CTM DESKTOP FRONT PANEL CABLE A N D CONNECTOR IMPLEMENTA TION DOCUMENT Revision July 14, 2017 Copyright 2016 USB Implementers Forum, Inc. All rights reserved. USB FRONT-PANEL INTERNAL CABLE AND CONNECTOR USB FRONT-PANEL INTERNAL CONNECTOR AND CABLE, REVISION ii Copyright 2016, USB Implementers Forum, Inc. All rights reserved. Legal Disclaimers A LICENSE IS HEREBY GRANTED TO REPRODUCE THIS DOCUMENT FOR INTERNAL USE ONLY. NO OTHER LICENSE, EXPRESS OR IMPLIED, BY ESTOPPEL OR OTHERWISE, IS GRANTED OR INTENDED HEREBY. USB-IF AND THE AUTHORS OF THIS DOCUMENT EXPRESSLY DISCLAIM ALL LIABILITY FOR INFRINGEMENT OF INTELLECTUAL PROPERTY RIGHTS, RELATING TO IMPLEMENTATION OF INFORMATION IN THIS DOCUMENT. USB-IF AND THE AUTHORS OF THIS DOCUMENT ALSO DO NOT WARRANT OR REPRESENT THAT SUCH IMPLEMENTATION(S) WILL NOT INFRINGE THE INTELLECTUAL PROPERTY RIGHTS OF OTHERS.

2 THIS DOCUMENT IS PROVIDED "AS IS AND WITH NO WARRANTIES, EXPRESS OR IMPLIED, STATUTORY OR OTHERWISE. ALL WARRANTIES ARE EXPRESSLY DISCLAIMED. NO WARRANTY OF MERCHANTABILITY, NO WARRANTY OF NON-INFRINGEMENT, NO WARRANTY OF FITNESS FOR ANY PARTICULAR PURPOSE, AND NO WARRANTY ARISING OUT OF ANY PROPOSAL, SPECIFICATION, OR SAMPLE. THE PROVISION OF THIS DOCUMENT TO YOU DOES NOT PROVIDE YOU WITH ANY LICENSE, EXPRESS OR IMPLIED, BY ESTOPPEL OR OTHERWISE, TO ANY INTELLECTUAL PROPERTY RIGHTS. USB Type-C and USB-C are trademarks of the Universal Serial Bus Implementers Forum (USB-IF). All product names are trademarks, registered trademarks, or service marks of their respective owners USB FRONT-PANEL INTERNAL CABLE AND CONNECTOR USB FRONT-PANEL INTERNAL CONNECTOR AND CABLE, REVISION iii REVISION HISTORY Date Document Version Revisions 01-17-2017 Rev. First release July-14-2017 Rev.

3 Updated Key-B drawings USB FRONT-PANEL INTERNAL CABLE AND CONNECTOR USB FRONT-PANEL INTERNAL CONNECTOR AND CABLE, REVISION iv CONTENTS 1. Introduction _____ 5 2. Mating Interfaces and Mechanical Requirements _____ 6 20-Pin Header .. 6 Mating Interface .. 6 Reference Footprint .. 11 40-Pin Header .. 12 Mating Interface .. 12 Reference Footprint .. 15 Important Implementation Notes .. 15 Mechanical Requirements .. 17 3. SIGNALS, PIN-OUTS AND WIRING _____ 18 Signal Lists .. 18 Pin-outs and Wiring .. 19 Key-A 20-Pin Connector .. 19 20-Pin Plug to One USB Type-C Port .. 19 20-Pin Plug to One Standard-A Port .. 20 Key-B 20-Pin Connector .. 21 40-Pin Connector .. 22 40-Pin Connector to Two USB Type-C Ports .. 22 40-Pin Connector to one USB Type-C Port and one Standard-A Port .. 24 40-Pin Connector to two Standard-A Ports .. 25 4. Electrical Requirements _____ 27 Loss Budget.

4 27 Signal Integrity Requirements .. 28 Raw 28 Mated Connector 28 Mated Cable Assemblies .. 29 DC Requirements .. 31 Mated connector current carrying requirements .. 31 Cable assembly IR drop requirement .. 32 USB FRONT-PANEL INTERNAL CABLE AND CONNECTOR USB FRONT-PANEL INTERNAL CONNECTOR AND CABLE, REVISION 5 1. IN T R O D U C T I O N Desktop PC s usually have USB ports on the front-panel of the enclosure and an internal cable assembly is typically used to connect the external USB ports on the front panel to the motherboard. The internal cable assembly may connect the motherboard to the external USB ports via a daughter card, or direct-connect to the external USB ports or receptacle connectors. Figure 1-1 illustrates those two interconnect topologies. A redriver/retimer may be needed on the daughter card in the daughter-card topology, depending on the daughter card design.

5 Figure 1-1: Illustration of USB Interconnect Topologies with Internal Cable The purpose of this document is to help PC manufacturers to implement USB Standard-A and USB Type-C connectors for desktop front-panel applications. It provides reference designs of the front panel connectors and cable assemblies, and describes their electrical and mechanical requirements. This document is not part of the USB base specifications. Implementers may choose to deviate from the defined reference designs, but it is strongly recommended that the electrical requirements specified in this document be followed. USB FRONT-PANEL INTERNAL CABLE AND CONNECTOR USB FRONT-PANEL INTERNAL CONNECTOR AND CABLE, REVISION 6 2. MAT I N G IN T E R FA C ES A N D ME C H A N I C A L RE Q U I R E M E N T S The receptacle connector mounted on motherboard (MB) is referred to as the header. To provide configuration flexibility of the USB ports on the front panel, this document defines a 20-pin and a 40-pin header.

6 The 20-pin header has two keying options. The 20-pin header with Key-A supports 1 USB Type-C port or 1 Standard-A port. The 20-pin header with Key-B supports 2 Standard-A ports. 20-Pin Header Mating Interface Figure 2-1 shows the reference design of the Key-A 20-pin shielded header, while Figure 2-2 shows the reference design of the Key-A 20-pin unshielded header. The shielded header is to mitigate radio frequency interference (RFI) risk for the systems where RFI is a concern. The unshielded header may be used if the RFI risk is deemed low. Note: (1) A right-angle header is allowed. Figure 2-1: Reference Design of Key-A 20-pin Shielded Header USB FRONT-PANEL INTERNAL CABLE AND CONNECTOR USB FRONT-PANEL INTERNAL CONNECTOR AND CABLE, REVISION 7 Figure 2-2: Reference Design of Key-A 20-pin Un-shielded Header Figure 2-3 shows the reference design of the Key-B 20-pin shielded header, while Figure 2-4 shows the reference design of the Key-B 20-pin unshielded header.

7 The shielded header is to mitigate radio frequency interference (RFI) for the systems where RFI is a concern. The unshielded header may be used if the RFI risk is deemed low. USB FRONT-PANEL INTERNAL CABLE AND CONNECTOR USB FRONT-PANEL INTERNAL CONNECTOR AND CABLE, REVISION 8 Figure 2-3: Reference Design of Key-B 20-pin Shielded Header USB FRONT-PANEL INTERNAL CABLE AND CONNECTOR USB FRONT-PANEL INTERNAL CONNECTOR AND CABLE, REVISION 9 Figure 2-4: Reference Design of Key-B 20-pin Un-shielded Header Figure 2-5 shows the reference design of the Key-A 20-pin plug, while Figure 2-6 shows the reference design of the Key-B 20-pin plug. The Key-A plug can only be plugged into the Key-A header. The same is true for the Key-B plug and header. USB FRONT-PANEL INTERNAL CABLE AND CONNECTOR USB FRONT-PANEL INTERNAL CONNECTOR AND CABLE, REVISION 10 Note: (1) A right-angle cable plug is allowed.

8 (2) Metal shell feature (see Figure 2-13) is required to ensure the plug can mate with the shielded header. Figure 2-5: Reference Design of Key-A 20-Pin Cable Plug Interface Dimensions USB FRONT-PANEL INTERNAL CABLE AND CONNECTOR USB FRONT-PANEL INTERNAL CONNECTOR AND CABLE, REVISION 11 Note: (1) A right-angle cable plug is allowed. (2) Metal shell feature (see Figure 2-13) is required to ensure the plug can mate with the shielded header. Figure 2-6: Reference Design of Key-B 20-Pin Cable Plug Interface Dimensions Reference Footprint Figure 2-7 shows the reference footprints for the 20-pin headers defined in Section USB FRONT-PANEL INTERNAL CABLE AND CONNECTOR USB FRONT-PANEL INTERNAL CONNECTOR AND CABLE, REVISION 12 Figure 2-7: Recommended Footprint for 20-Pin Headers 40-Pin Header Mating Interface The 40-pin header/plug is a simple extension of the 20-pin header/plug with the only difference being the pin count.

9 Figure 2-8, Figure 2-9 and Figure 2-10 show the 40-pin header and cable plug mating interface dimensions, respectively. USB FRONT-PANEL INTERNAL CABLE AND CONNECTOR USB FRONT-PANEL INTERNAL CONNECTOR AND CABLE, REVISION 13 Note: (1) A right-angle header is allowed. Figure 2-8: Reference Design of Shielded 40-Pin Shielded Header USB FRONT-PANEL INTERNAL CABLE AND CONNECTOR USB FRONT-PANEL INTERNAL CONNECTOR AND CABLE, REVISION 14 Figure 2-9: Reference Design of 40-Pin Unshielded Header Note: (1) A right-angle cable plug is allowed. (2) Metal shell feature is required to ensure the plug can mate with the shielded header. Figure 2-10: Reference Design of 40-Pin Cable Plug USB FRONT-PANEL INTERNAL CABLE AND CONNECTOR USB FRONT-PANEL INTERNAL CONNECTOR AND CABLE, REVISION 15 Reference Footprint Figure 2-9 shows the reference footprints for the 40-pin headers defined in Section Figure 2-11: Recommended Footprints for 40-Pin Headers Important Implementation Notes The followings should be noticed: 1.

10 Orientation arrow mark is required on both header and plug. The mark is located in the length direction near pin-3 position. The examples of header arrow mark and plug arrow mark are shown in Figure 2-12 Figure 2-12: Reference Design of alignment arrow marks of header and plug 2. To easily differentiate Key-A 20-pin header and Key-B 20-pin header, it is recommended to use black color for Key-A 20-pin header and plug, and use nature or white color for Key-B 20-pin header and plug. 3. The reference design is much more compact in size than the USB header and therefore more suitable for not only desktops in standard chassis but also smaller form factors. 4. The mated connector is illustrated in Figure 2-13. A right-angle plug may be used. Note that the 19 mm dimension represents the minimum height that may be achieved in one implementation. In general, the mated height may be larger than this.