The PS8778 is a bidirectional 4-lane linear Redriver that reconditions USB and DP signals, compliant with USB4, USB 3.2, and DP2.1a specifications. It supports USB4 Gen3 speeds up to 20Gbps and DP UHBR20 per lane, ensuring high-speed signal quality for USB-C topologies. Applicable on both host and device sides, including USB-C active cables, its operation mode, EQ, and DC gain are configurable via I2C for tailored signal compensation. It supports lane and P/N polarity swaps and consumes low power, with full USB4, USB 3.2, and DP2.1a link power management. The chip detects sideband signals from DP mode (AUX) and Thunderbolt3/USB4 mode (SBTX/RX) to optimize configuration and power-saving modes. Operating on a 1.8V supply, it comes in a compact QFN package. The PS8778 also features an automatic power-saving mode, entering low power when channels are idle and resuming normal function upon signal detection.

Functional Block Diagram

 

Cascading Application for MB Design

Active Cable Application

Key features:

  • Low Power Consumption: 290mW@20Gbps, USB4/DP2.1
  • Extreme Low Standby Power: 0.5mW, modern standby compliant
  • Bidirectional redriving: Easy for cable applications
  • Single 1.8V supply
  • Compact Size: comes with 2.8×4.4mm 28-pin QFN package.

The PS8778 supports multiple operation modes:

  • USB4 gen3@20Gbps x2 & x1
  • USB4 asymmetric link: (TX or RX) x3@20Gbps, (RX or TX) x1@20Gbps
  • Thunderbolt 4: 20.625Gbps, 10.3125Gbps
  • USB3.2: x2 & x1@10Gbps, x2 & x1@5Gbps
  • DP Alt mode: USB3.2 10Gbps & 5Gbps, DP up to 20Gbps on one/two lanes; four lanes for all data rates up to 20Gbps

Applications

  • Desktop and laptop computers
  • Active cables
  • Workstations