8T49N282C-998NLGI

Overview

The 8T49N282C-998NLGI is an Octal Universal Frequency Translator from the FemtoClock NG family. It features two independent fractional-feedback PLLs capable of jitter attenuation and frequency translation. The device generates up to eight output frequencies ranging from 8kHz to 1GHz using six integer and two fractional output dividers. It accepts up to four differential or single-ended input clocks plus a crystal input, supporting LVPECL, LVDS, LVHSTL, HCSL, and LVCMOS levels. Key electrical parameters include <0.3ps RMS phase jitter (including spurs) at 12kHz to 20MHz for differential outputs and <0.5ps RMS for all outputs. It operates from 2.375V to 3.465V supplies in a 72-lead QFN package.

Feature Summary

• Two independent PLLs with fractional feedback for jitter attenuation and frequency translation
• Generates up to eight output frequencies (8kHz to 1GHz) via six integer and two fractional dividers
• <0.3ps RMS phase jitter (including spurs) at 12kHz to 20MHz for differential outputs
• Supports hitless reference switching and holdover with ±50ppb initial accuracy

Applications

• OTN or SONET/SDH equipment line cards (up to OC-192)
• Gigabit and Terabit IP switches/routers with Synchronous Ethernet support
• Wireless base station baseband units
• Data communications networking equipment

Procurement Notes

Verify the ordering suffix '998' corresponds to the specific factory pre-programmed configuration required for the application. Confirm that the 72QFN package dimensions and pinout match the PCB footprint. Ensure I2C/SPI interface compatibility with the system controller. Check moisture sensitivity level (MSL 3) handling requirements during assembly.

Selection Notes

Select this component when dual independent PLL paths are needed for separate transmit/receive clock domains. Verify that the input frequency range (8kHz to 875MHz) and output frequency range (up to 1GHz) cover the design requirements. Consider the loop bandwidth options (0.5Hz to 512Hz) for jitter filtering needs. Ensure the power supply voltages (VCC/VCCA/VCCO) align with the system's available rails.

Part Context

The 8T49N282 is part of the FemtoClock NG Octal Universal Frequency Translator series by Renesas Electronics (formerly IDT). It is designed for high-performance networking applications requiring precise clock generation and jitter attenuation. The device integrates multiple output drivers and programmable logic to replace discrete clock components.

Replacement Considerations

Direct replacements within the same family include other 8T49N282 variants with different ordering suffixes for distinct factory configurations. Cross-family substitutes like the 8T49N242 offer fewer outputs and PLLs. Verify pin-to-pin compatibility and register software compatibility before substitution.