SNLA381 March   2021

 

  1.   Trademarks
  2. 1Introduction – Automotive Industry Trends in ADAS and Vehicle Connectivity
  3. 2PCIe for Automotive ECU-to-ECU Interconnects
    1. 2.1 Advantages of PCIe Technology
    2. 2.2 PCIe and Multigig Ethernet Co-Existence in the Automotive Data Backbone
  4. 3PCIe Signal Conditioning for Intra-ECU and Inter-ECU Interfaces
  5. 4Conclusion

3 PCIe Signal Conditioning for Intra-ECU and Inter-ECU Interfaces

Redrivers and retimers are needed to recover and counteract the additional insertion loss and signal-to-noise ratio degradation that naturally occur when transporting PCIe over lossy media, whether that is through PCB or automotive cable channels. Both redrivers and retimers have a deep-rooted history in the PCIe ecosystem. Redrivers have been a part of the PCI-SIG Integrator’s List of approved components since PCIe 2.0. Meanwhile, retimers formally became part of the PCIe Base Specification since PCIe 4.0. TI offers the industry’s largest portfolio of PCIe redrivers, retimers, and passive switches to address a multitude of industrial and automotive use cases.

Table 3-1 Linear Redriver vs. Retimer Comparison
PCIe Linear Redriver (1) PCIe Retimer
Low power consumption solution (no heat sink is required) High power consumption solution (most cases require heat sink)
Ultra-low latency (100 ps) Medium latency (less than or equal to 64 ns based on PCIe 4.0 Specification Requirement)

Does not participate in link training but is transparent to negotiations between Root Complex (CPU) and Endpoint (EP)

(Protocol agnostic)

Fully participates in link training with Root Complex (CPU) and Endpoint (EP)

(Protocol aware)
No 100-MHz reference clock is required 100-MHz reference clock is required
Helps with insertion loss Helps with insertion loss, jitter, crosstalk, reflections and lane-to-lane skew
CTLE is the typical equalization circuit used CTLE, DFE and transmitter FIR are typical equalization circuits used
Total solution cost is ~X Total solution cost is ~(1.3X - 1.5X)
(1) For additional comparison details, refer to the technical article Signal Conditioning functions go mainstream in PCI Express Gen 4.