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Backward Compatible and PCIe 4.0 Compliant, 2.5Gbps to 16Gbps Linear Redriver

Diodes Incorporated introduced a redriver for the server, storage, and networking market segment. The PI3EQX16904GL is a PCIe 4.0 compliant, 2.5Gbps to 16Gbps, four-differential channel, linear redriver. Diodes claims that it is the industry’s first available redriver to support PCIe 4.0 while being backward-compatible with PCIe 3.0/2.0/1.0.

Target applications for the device include storage and AI servers, workstations, 5G networking, CPU-to-network (PCIe NIC card) and CPU-to-storage (NVME) interconnects, and CPU-to-CPU interconnects within high-performance compute clusters.

The device offers programmable linear equalization, output swing, and flat gain for optimizing performance over a variety of physical media. The optimal performance is the result of reducing inter-symbol interference. The equalization is controlled by either the pin-strapping option or I2C Control.

PI3EQX16904GL Redriver block diagram (Click on image to enlarge)

The redriver, also known as a repeater IC, regenerates signals to boost the signal quality of high-speed interfaces. Faster signal frequencies leave designers with less signal margin with which to design reliable, high-performance systems. Using equalization, pre-emphasis, and other technologies, a single redriver can adjust and correct for known channel losses at the transmitter and restore signal integrity at the receiver. This adjustment and correction enables reliable communications with low bit error rates (BER). Linear redrivers are often used to achieve PCB trace extension while minimizing cost and power consumption. They can also lower latency.

The PI3EQX16904GL supports four 100Ω differential current mode logic (CML) data I/Os, and it extends the signals across other distant data pathways on the user’s platform.

Requiring a supply voltage of 3.3V ±0.3V, the device can operate over an industrial temperature range of -40˚C to +85˚C. The PI3EQX16904GL ReDriver is available in a 42-contact TQFN (9mm x 3.5mm) package.

The company points out that the integrated equalization circuitry provides flexibility with signal integrity of the signal before the redriver. Whereas, the integrated linear amplifier/buffer circuitry provides flexibility with signal integrity of the signal after the redriver.

Features
  • 2.5Gbps to 16Gbps serial link with linear equalizer
  • Supports SAS3/ IB FDR/ PCIe4/ FC16, and XAUI protocols
  • Supporting 4 differential channels
  • Independent channel configuration of receiver equalization, output swing and flat gain
  • Rate and Coding Agnostic
  • Transparent to link training, Idle
  • Pin strap and I2C selectable device programming
  • 3-bit selectable address bit for I2C
  • Supply Voltage: 3.3V±0.3V
  • Industrial Temperature Range: -40˚C to 85˚C
  • Pin strap value latched into I2C register