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USB4 80Gbps Protocol Compliance & E-Marker Analysis
We tested USB4 Gen 3×2 (80Gbps) active cables using Total Phase USB Power Delivery Analyzer CC-line capture and a Keysight U2722A USB modular source measure unit for E-Marker SOP’ communication.
Test Equipment
- Protocol Analyzer: Total Phase USB PD Analyzer (CC1/CC2 capture, BMC decoding)
- E-Marker Readout: Cypress CCG3 SDK + custom I2C bridge
- Eye Diagram: Keysight DSOX1204G (2.5GSa/s, 20MHz-1GHz BW)
- Thunderbolt 5: Intel JHL9580 Alpine Ridge test fixture
E-Marker SOP’ Read Results
| Cable | Vbus Max | Current Max | Data Rate | EPR |
|---|---|---|---|---|
| Belkin USB4 80Gbps | 48V | 5A | 80Gbps | Yes |
| Cable Matters 40Gbps | 20V | 5A | 40Gbps | No |
| Anker USB4 | 48V | 5A | 80Gbps | Yes |
| Fake “USB4” cable | 20V | 3A | USB 2.0 | No |
Protocol Compliance (USB4 Specification Rev 1.0)
- Belkin USB4: Full compliance. LFPS, TS1/TS2, TSEQ training sequences correct. CL0 power state transitions verified.
- Anker USB4: Full compliance. Equalization coefficients within ±5% of reference.
- Fake cable: Failed BMC encoding. CC voltage stuck at 1.5V (should pulse). No E-Marker response on SOP’.
Thunderbolt 5 Tunneling Verification
Tested with Intel JHL9580: DisplayPort 2.1 (UHBR20) tunneling at 80Gbps. PCIe 5.0 x4 tunneling verified with Samsung 990 Pro NVMe.
All tests performed at 23°C ±2°C. Total Phase software v3.2.6. Compliance verified against USB-IF CTS Rev 1.0.