The everlasting presence of the USB interface is evident with close to 5+ billion USB devices shipped each year. USB has always been the cornerstone of the consumer electronics market. USB Type-A and Type-B cables, interface and connectors have been ubiquitous on variety of devices – smartphones, PCs, video games, power backups, and automotive etc. With the technology always pushing towards better, thinner and power efficient devices, the native cable assemblies have been the bottleneck to innovation in this space. Limitations of native USB standard were so obvious that competitors like thunderbolt were always around the corner ready to get a slice of the massive USB market. In mid-2014, the USB Type-C standard was announced, which provided the ever evolving ecosystem of new platforms with existing benefits of USB standard (2.0, Gen1, Gen2).
Type-C PIN Structure
Four pair of differential pins meant for Gen1, Gen2 USB or for use with third party peripherals in alternate mode. Presence of 4 pairs enables Type-C to use a composite arrangement like USB 3.1 with 2 Lane Display Port. A2, A3, B2, B3, A10, A11, B10, B11 represent the SS differential pins.
Two pair of Non-Super Speed differential pins for USB 2.0. – A6, A7, B6, B7.
Four pins each for VBUS and Ground (VBUS: A4, A9, B9, B4 and Ground: A1, A12, B1, B12).
Two pairs of CC (configuration channel) for Power Delivery and Sideband usage. CC – A5, B5, Sideband – A8, B8.
Presence of multiple pins for each functionality enables Type-C to be used in flipped mode.
Form factor – Type-C interface has relatively smaller and thinner plug assembly with 24 pins that replaces existing plug assemblies – mini and micro plugs. The Type-C is thinner than the thinnest available ‘micro-B’ (for SS/SSP as well) plug. So, one cable for all your devices – and thinner assemblies.
Backward compatibility – It is seamlessly backward compatible to the available assemblies since the underlying standard remains the same. All the latest devices, be it Apple’s MacBook or Google’s Pixel phone, Samsung Galaxy S8 etc., all support the Type-C standard.
Power requirements – Type-C is compliant with Power Delivery specifications. Type-C cable assembly either of the device or host could be used as source or sink to deliver or consume power. It is possible because Power Delivery has power role change capability and power negotiation capability to higher power. Power Delivery devices can supply 100 watts which is more than sufficient to charge a laptop. Hence using Type-C cable you can charge or even power up a device.
Ease of Use – Type-C is reversible and can be connected in either orientation, which solves a very basic problem with native USB plugs where the plug never fits the first time. There are duplicate pins available that can help the cable connect in either straight or flipped orientation.
Alternate Mode – This is one area that proves that with Type-C, it is not just about USB. Using alternate mode, Type-C cable can connect to third party peripherals other than USB. Some of the peripherals supported are Display Port, MHL, Thunderbolt 3 and most recently HDMI. Alternate Mode must be performed using VDM (Vendor Defined Message) exchanges on CC pin (Power Delivery). This is another way to reduce form factor by supporting multiple peripherals on same connector.