USB-C ports look identical—but charging speed, data bandwidth, video support, and cable capability can be completely different.
Here’s the engineering behind USB-C, USB Power Delivery, USB4, Thunderbolt, e-marker chips, and the PCB itself.
USB-C was supposed to make connectivity simpler.
The connector became universal.
The capability behind it didn't.
In this episode of Silicon to Software, Imran Valiani breaks down what actually happens when you plug in a USB-C cable—and why two identical-looking ports can deliver radically different results.
We start with the 24-pin USB Type-C connector and the CC1/CC2 configuration channels responsible for orientation, power roles, and USB Power Delivery negotiation.
Then we go inside the cable itself.
Higher-power USB-C cables can contain an e-marker chip that identifies the cable's capabilities to the connected hardware. That becomes critical as USB Power Delivery moves beyond standard 3A operation and into 5A cables capable of supporting up to 240W under Extended Power Range.
But power is only part of the story.
USB-C can carry everything from USB 2.0 to USB4 40Gbps and the newer USB 80Gbps tier. DisplayPort Alt Mode and Thunderbolt add another layer of capability—all behind a connector that can look exactly the same from the outside.
And at those speeds, the PCB becomes part of the channel.
We examine:
• USB-C CC1 and CC2 negotiation
• USB Power Delivery (USB PD)
• E-marker chips and 60W vs. 240W cables
• USB 2.0 vs. USB4 40Gbps vs. USB 80Gbps
• Thunderbolt 4 and Thunderbolt 5
• DisplayPort Alt Mode
• Controlled-impedance differential pairs
• PCB vias and via-stub reflections
• Retimers, redrivers, and muxes
• Signal-integrity and insertion-loss constraints
• Why identical USB-C ports can have different capabilities
The connector isn't the promise.
The silicon, cable, and PCB behind it are.
READ THE FULL ENGINEERING BREAKDOWN
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ABOUT SILICON TO SOFTWARE
Silicon to Software examines the hardware layer behind modern technology—from PCB manufacturing and semiconductor packaging to embedded electronics, AI infrastructure, automotive systems, and high-speed hardware.
Hosted by Imran Valiani, with 20+ years of experience in PCB electronics manufacturing and technology sales.
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