8T49N242-999NLGI8

Specialized ICS Overview

The Renesas 8T49N242-999NLGI8 is a FemtoClock NG Universal Frequency Translator housed in a 40-VFQFPN (6x6mm) package. It features one fractional-feedback PLL and four integer output dividers, generating up to four independent output frequencies from 8kHz to 1GHz (differential) or 250MHz (LVCMOS). The device accepts two differential/single-ended input clocks (8kHz–875MHz) plus a fundamental-mode crystal (10MHz–50MHz). It supports LVPECL, LVDS, HCSL, and LVCMOS outputs with 2.5V/3.3V supply modes. Key specifications include 0.35ps RMS typical jitter (12kHz–20MHz), ±50ppb initial holdover accuracy, and I2C programmability.

Specialized ICS Feature Summary

• Generates up to four independent output frequencies ranging from 8kHz to 1.0GHz using integer dividers.
• Supports hitless reference switching between two input clocks with automatic/manual selection and Loss-of-Signal monitoring.
• Provides 0.35ps RMS typical jitter performance (12kHz to 20MHz) and ±50ppb initial holdover accuracy.
• Configurable via I2C interface with support for external EEPROM programming and Timing Commander software.

Specialized ICS Applications

• OTN or SONET/SDH equipment
• Gigabit and Terabit IP switches/routers including Synchronous Ethernet
• Video broadcast systems

Specialized ICS Procurement Notes

Verify the ordering suffix '999' indicates factory pre-programmed configuration behavior distinct from other variants like '998'. Confirm RoHS 6 compliance and lead-free status. Ensure the 40-VFQFPN exposed pad thermal requirements are met during assembly. Check for specific PCNs regarding material or assembly site changes.

Specialized ICS Selection Notes

Select this component when four independent clock outputs are required with low jitter performance. Ensure input frequencies fall within the 8kHz to 875MHz range. Verify that the required output voltage levels (1.8V, 2.5V, or 3.3V) match the available VCCO supplies. Consider the need for hitless switching and holdover capabilities for synchronization applications.

Specialized ICS Part Context

The 8T49N242 belongs to the FemtoClock NG family of universal frequency translators. It integrates a fractional-feedback PLL with multiple integer output dividers. The device is designed for high-performance timing applications requiring flexible frequency synthesis and jitter attenuation across various communication standards.

Specialized ICS Replacement Considerations

Public confirmed substitute part numbers: 8T49N242-998NLGI8, 8T49N241-994NLGI8, 8T49N241-998NLGI8, 8T49N242-998NLGI, 8T49N242-999NLGI.

Specialized ICS FAQ

What is the maximum differential output frequency?

The maximum differential output frequency is 1.0 GHz.

How does the device handle input clock failure?

The device monitors inputs for Loss of Signal (LOS) and supports automatic or manual hitless switching to a backup input. If no valid inputs remain, it enters holdover mode with ±50ppb initial accuracy.

Can the outputs be configured as single-ended?

Yes, the outputs can be configured as LVCMOS, providing up to eight single-ended outputs (using both Q and nQ pins) at frequencies up to 250 MHz.