SNLA381 March 2021
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.
| 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) |