8T49N242-998NLGI#

Overview

The 8T49N242-998NLGI is a FemtoClock NG Universal Frequency Translator (UFT) manufactured by Renesas Electronics. It integrates one fractional-feedback PLL and four integer output dividers to generate up to four independent output frequencies ranging from 8kHz to 1GHz. The device supports differential outputs (LVPECL, LVDS, HCSL) and single-ended LVCMOS levels. It accepts up to two input clocks or a crystal oscillator, with supply voltage operating between 2.375V and 3.465V. Key electrical specifications include an RMS jitter of 0.276ps (12kHz to 20MHz). The component is housed in a 40-VFQFN package with an exposed pad.

Feature Summary

• Generates up to four independent output frequencies from 8kHz to 1GHz using one PLL and four integer dividers
• Supports multiple output standards including LVPECL, LVDS, HCSL, and LVCMOS
• Accepts dual inputs (LVPECL, LVDS, LVHSTL, HCSL, LVCMOS) or fundamental-mode crystal
• Features hitless switching and phase-slope limiting for controlled output phase transients
• Programmable via I2C interface or external EEPROM boot configuration

Applications

• 10G/40G/100G SONET/SDH and Ethernet network line cards
• GbE/10GbE/100GbE Synchronous Ethernet line card applications preserving G.8262 compliance
• Wireless base station baseband units
• Carrier Ethernet switches and OTN equipment
• Broadcast video and test and measurement applications

Procurement Notes

Verify the specific suffix '998' indicates the 'Boot from EEPROM' configuration variant as documented in the datasheet. Confirm moisture sensitivity level (MSL 3) and reflow soldering profiles during procurement planning. Check current availability status as lead times may vary. Ensure the ordering part number matches the exact package and temperature range requirements for the target design.

Selection Notes

Select this model when four independent output frequencies are required from a single clock source. The device is suitable for designs needing jitter attenuation or frequency synthesis with low phase noise. Consider the 40-VFQFN package size for PCB layout constraints. Verify that the required output voltage levels (LVPECL/LVDS vs LVCMOS) align with the system's receiver inputs. Use Timing Commander software for register configuration and validation.

Part Context

This component belongs to the Renesas FemtoClock NG family of universal frequency translators. It shares architectural similarities with the 8T49N241, which features fractional output dividers instead of integer dividers. The 8T49N242 series is designed to replace legacy clock generators in high-speed networking and telecommunications infrastructure requiring precise timing and jitter management.

Replacement Considerations

Public confirmed substitute part numbers are not available in the provided documentation. Designers should consult the official Renesas/SiTime cross-reference tools for potential alternatives.