Redriver From Diodes Incorporated Aims for 8Gbps Speeds With Linear Equalizer

January 24, 2020 by Gary Elinoff

The PI3EQX12904A supports flexible interfacing and features low-standby power requirements.

Solid-state drives (SSDs) continue to displace HDDs in a range of electronic systems. Developers then need interfacing devices that can drive the longer PCB track lengths and will not allow the transmitted signal to degrade.



The PI3EQX12904A. Image used courtesy of Diodes Incorporated

Diodes Incorporated says its new PI3EQX12904A complies with both SATA and PCIe protocols, which lends this component for use in a number of electronics. 


What is a Redriver?

According to Diodes Incorporated, faster signal frequencies leave designers with less signal margin with which to design stable, reliable systems.

A redriver serves to regenerate signals to boost the signal quality of high-speed interfaces. It employs technologies such as equalization and pre-emphasis to adjust and correct known channel losses and to restore signal integrity at the receiver.

Redrivers offer better performance then protocol-based signal repeaters. Signal repeaters serve as endpoints that actually terminate and then retransmit the signal. This introduces delays as well as extra system costs.

Another key advantage is that redrivers minimize jitter through conditioning and by passing signals through at the physical layer.


Redrivers protect signal Integrity

Redrivers protect signal Integrity. Image used courtesy of Diodes Incorporated


Most redrivers can deliver extra drive to transmit control and data signals across switch fabrics, cables, or PCB tracks. The PI3EQX12904A also adds linear swing, programmable equalization, and flat gain capability to the mix, delivering what Diodes Incorporated refers to as "optimal performance"—regardless of the physical medium. 


Features of the PI3EQX12904A

The PI3EQX12904A supports transmission over PCIe 3.0 at 8Gbs and over SATA3 protocols at 6Gbps. The device features four 100Ω differentials CML (current mode logic) signal pathways.

Receiver equalization, output linear swing, and flat gain are all separately programmable. This serves to improve performance over a range of physical media by reducing intersymbol interference. 

Flexibility with the signal’s integrity both before and after the redriver is provided by the integrated equalization circuitry.


Application diagram of the PI3EQX12904A

Application diagram of the PI3EQX12904A. Image used courtesy of Diodes Incorporated


The unit is aimed at supporting the latest processor chipsets, mSTATA and SATAe connectors, M.2 connectors, and expansion cards.


Adaptive Power Management

The device’s adaptive power management facility provides a low-power mode, which automatically monitors each pathway. When in slumber mode, the inputs are monitored for activity. Each of the four channels is independent of the other three. When renewed activity is detected in any one of them, that channel alone awakes and automatically switches back to active mode.


Block diagram of the PI3EQX12904A

Block diagram of the PI3EQX12904A. Image used courtesy of Diodes Incorporated


This crucial feature enables the PI3EQX12904A to use far less power than devices without this capability.


Electrical, Environmental, and Physical Considerations

The unit operates with a supply voltage of 3.3 V ± 0.3 V. Halogen- and Antimony-free, the PI3EQX12904A is a “green” device. It is also lead-free and RoHS compliant.

The operating temperature range is from -40°C to 85°C.

The unit is offered in a 42-pin, 3.5 mm × 9 mm TQFN (ZH42) package.



Diodes Incorporated has expressed that they see PI3EQX12904A being useful in a number of applications, including notebooks, personal computers, data storage systems, embedded designs, and server systems.


Around the Industry

The TUSB1002A from Texas Instruments is a dual-channel USB3.2 x1 redriver, operating at a maximum speed of 10 Gbps. The unit takes a 3.3 V power supply and draws less than 300 mW when active.

NXP offers an array of USB 3.0 redrivers. The PTN36001 is a dual-channel unit with each channel supporting a 5 Gbps signal rate.