PAM4 for High-Speed Links
Datacenters are deploying higher throughout links to accommodate increasing bandwidth demands. This is making the timing margin in transceivers more important, while at the same time, formfactors are shrinking and operating environments are becoming denser and hotter.
SiTime precision timing solutions are ideal for high-speed links, 400Gbps and higher. These MEMS-based devices meet demanding jitter requirement in small footprint packages, and have excellent immunity to temperature transients, power supply noise, and other environmental hazards.
SiTime MEMS Timing Benefits
Complete MEMS clock treeLow jitter differential MEMS XO Low jitter clock generator |
More robust in real-world conditions105°C, resistant to airflow and heat Immunity to power supply noise Better frequency stability and reliability |
Small size, easy to useSmall footprints ≤1 mm thin that fits back of a card No quartz reliability issues |
PAM4 based High-Speed Links Block Diagrams
400G Optical module
Multi-port Network Switch SoC
MEMS Timing for PAM4 High-Speed Links
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Differential Oscillators
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Clock Generator
SiT91211 [2] 1 to 750 MHz,
200 fs Integrated Phase Jitter [1] SiT91213 [2] 1 to 750 MHz,
90 fs Integrated Phase Jitter [1] |
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[1] 12 kHz to 20 MHz integration range; [2] Contact SiTime for availability
Datacenters require extremely reliable 200Gbps, 400Gbps or higher throughput links to sustain data traffic generated by increasing user application loads in dense rack-based servers. PAM4 stands for pulse amplitude modulation, 4-Level. This is the critical piece of technology that enables high-speed, 400Gbps and 800Gbps links.
Increasing demand for Ethernet bandwidth is pushing networking infrastructure vendors and datacenter vendors towards higher speeds over Ethernet. Most networking infrastructure, like routers, switches and Ethernet links in datacenters, have deployed 400Gbps links and are already planning for 800Gbps links.
High speed Ethernet links (10Gbps and higher) initiated the move towards adopting PAM4 but 400Gbps and 800Gbps rates are impossible to achieve without PAM4. Advances in PCB fabrication technology with tighter tolerances on the signal traces, allowed for PAM4 to be deployed for high-speed SERDES links (56G and 112G) whereas better laser technology allowed for PAM4 to be deployed over fiber optic links.
Telecom infrastructure vendors depend on SiTime MEMS-based oscillators and clock products to meet and exceed the demands for increased data bandwidths from streaming content providers.
MEMS Timing Outperforms Quartz
Ultra-Low Phase Noise, 156.25 MHz |
Ultra-Low Phase Noise, 644.53125 MHz |
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Excellent Stability |
Better PSNR (Power Supply Noise Rejection) |
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Higher Reliability |
Smallest Packages |
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Resources
- Video: SiTime MEMS Timing Solutions for Optical Module
- Application: Optical Modules
- More information: See full list of related applications notes
