SIT92211AI-T

Clock Buffers, Drivers Overview

The SiTime SIT92211AI-T is a 10-output, differential ultra-low jitter clock fan-out buffer designed for high-frequency clock distribution and level translation. It supports input frequencies up to 2.1 GHz with an additive jitter performance of 55 fs RMS. The device features three selectable clock inputs: two universal inputs (CLKin0/1) accepting LVPECL, LVDS, LVCMOS, CML, HCSL, SSTL, or single-ended clocks, and one crystal input supporting 8 MHz to 50 MHz crystals. Outputs are distributed across two programmable differential banks (A and B) and one LVCMOS output (REFOUT). Differential outputs support LVPECL, LVDS, HCSL, or Hi-Z modes, while the LVCMOS output operates at 1.8 V, 2.5 V, or 3.3 V. The component operates from 3.3 V/2.5 V core and output supplies within a -40°C to 85°C temperature range.

Clock Buffers, Drivers Feature Summary

• Ultra-low additive jitter of 55 fs RMS (LVPECL/LVDS) and 60 fs RMS (LVDS specific conditions).
• Supports input frequencies up to 2.1 GHz with 3:1 input selection (2 universal + 1 crystal).
• Two independent output driver banks (A and B) configurable for LVPECL, LVDS, HCSL, or Hi-Z.
• Integrated LVCMOS reference output (REFOUT) synchronized to the selected clock source.

Clock Buffers, Drivers Applications

• PCI Express Gen1 through Gen5 clock distribution.
• High-speed data center and AI system timing.
• Telecommunications and networking infrastructure.
• Storage systems requiring low-jitter clock synchronization.

Clock Buffers, Drivers Procurement Notes

Verify the ordering suffix 'T' corresponds to the tape-and-reel packaging configuration as specified in the manufacturer's documentation. Confirm that the 'AI' suffix aligns with the required industrial temperature range (-40°C to 85°C) and voltage specifications. Ensure compatibility with the 48-pin QFN package dimensions for PCB layout. Cross-reference the specific part number against current distributor listings to confirm availability and lead times, as stock levels may vary.

Clock Buffers, Drivers Selection Notes

Select this component when designing systems requiring a 3:1 input mux with support for both differential and single-ended sources up to 2.1 GHz. It is suitable for applications needing simultaneous level translation between 3.3 V/2.5 V domains and 1.8 V LVCMOS logic. Consider the power supply requirements: separate VCCO supplies for Bank A, Bank B, and the LVCMOS output allow for independent voltage scaling. Ensure the application can accommodate the 48-pin 7mm x 7mm QFN package footprint and thermal dissipation needs.

Clock Buffers, Drivers Part Context

The SIT92211 belongs to the SiT92xxx series of high-performance clock buffers. It is distinct from lower-output variants like the SiT9211x series, which offer fewer outputs and smaller packages. This specific model provides a comprehensive solution for complex clock trees requiring multiple differential outputs and a reference clock, differentiating it from simpler fan-out buffers or oscillators.

Clock Buffers, Drivers Replacement Considerations

Direct parameter-equivalent substitutes include other SiTime models within the SIT92211 family with different packaging or temperature suffixes, such as SIT92211AI-X or SIT92211AI-Y. Verify pinout compatibility and electrical characteristics before substitution.

Clock Buffers, Drivers FAQ

What input signal types are supported by the universal clock inputs?

The universal clock inputs (CLKin0 and CLKin1) support LVPECL, LVDS, LVCMOS, CML (AC-coupled only), HCSL, SSTL, and single-ended clocks.

Can the crystal input accept an external clock signal?

Yes, the OSCIN pin can accept a single-ended clock signal in bypass mode or be over-driven by an AC-coupled single-ended clock in crystal over-drive mode.

What is the maximum operating frequency of the device?

The SiT92211 supports input and output frequencies up to 2.1 GHz.