8T49N242-999NLGI

Overview

The Renesas 8T49N242-999NLGI is a FemtoClock NG Universal Frequency Translator featuring one fractional-feedback PLL and four integer output dividers. It generates up to four independent output frequencies ranging from 8kHz to 1.0GHz (differential) or 250MHz (LVCMOS). The device accepts two differential or single-ended input clocks (8kHz–875MHz) and a fundamental-mode crystal (10MHz–50MHz). It supports LVPECL, LVDS, HCSL, and LVCMOS output levels with supply voltages of 2.5V or 3.3V for differential outputs and 1.8V for LVCMOS. Key electrical parameters include a typical jitter of 0.35ps RMS (12kHz to 20MHz), an initial holdover accuracy of ±50ppb, and programmable loop bandwidths from 0.2Hz to 6.4kHz.

Feature Summary

• Supports SDH/SONET and Synchronous Ethernet clock conversions including all FEC rates with 0ppm conversion error for most configurations.
• Generates four independent output frequencies using integer dividers ranging from ÷4 to ÷786,420.
• Features auto and manual hitless reference switching with clock input monitoring for gapped clocks.
• Programmable via I2C interface or external I2C EEPROM; includes four GPIO pins for status and control.

Applications

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

Procurement Notes

Verify the ordering suffix '999' indicates specific factory pre-programming behavior distinct from other variants like '998'. Confirm package type is 40-VFQFPN and check RoHS compliance status against current datasheet revisions before procurement.

Selection Notes

Select this component when designing frequency synthesis applications requiring independent output frequencies unrelated to input references. Ensure the application supports the required input voltage levels (2.5V/3.3V for differential, 1.8V for LVCMOS) and operates within the -40°C to 85°C temperature range.

Part Context

The 8T49N242 belongs to the FemtoClock NG family of Universal Frequency Translators. It integrates a fractional-feedback PLL with four integer output dividers, allowing it to function as both a jitter attenuator and a frequency synthesizer. The device is designed for high-performance timing applications in telecommunications and networking infrastructure.

Replacement Considerations

Public confirmed substitute part numbers are not available in the provided source material. Consult manufacturer documentation for potential cross-references or updated series replacements.