What is a retimer?A retimer is a device that reconstructs high-speed digital signals to extend reach and improve signal integrity in data transmission systems.
A retimer is a mixed-signal semiconductor device that receives a degraded high-speed digital signal, extracts the clock and data, and then retransmits a fresh copy of the original signal. Unlike simpler redrivers that only amplify signals, retimers can remove jitter, compensate for channel losses up to 35 dB, and are protocol-aware. They are essential in modern high-speed interfaces to maintain signal quality over longer distances or through challenging channels. In simple terms, a redriver just amplifies a signal, whereas a retimer fully recovers the data and sends out a crisp new copy.
When transitioning from the electrical to the optical domains, it is essential to send a clean signal into an optical link. Adding a retimer before transitioning to the optical domain ensures that your optical components are receiving a clean signal to be transmitted over the optical link.
In UCIe implementations, a UCIe retimer may be used to extend the UCIe connectivity beyond the package using an off-package interconnect. Examples of off-package interconnect include electrical cable or optical cable or any other technology to connect packages at a rack/pod level. Ayar Labs TeraPHY™ optical I/O chiplets can be used for extended distances — up to hundreds of meters — and will act as an optical retimer in UCIe designs.
A simplified data center example. Retimers in the middle of the on-board signal help the signal to reach the I/Os. Retimers right before the I/O ensure the cleanest signal going out onto the cables. Retimers right at the edge of the receiving board maximize interoperability by cleaning up a received signal regardless of where it originated.