8T49N240-991NLGI

Overview

The 8T49N240-991NLGI is a FemtoClock NG Universal Frequency Translator manufactured by Renesas Electronics. It functions as a clock synthesizer and jitter attenuator, generating up to four differential output frequencies ranging from 8 kHz to 867 MHz. The device accepts various input levels including LVPECL, LVDS, and HCSL. Key electrical specifications include an operating supply voltage of 2.375 V to 3.465 V and a maximum operating temperature of +85 °C. It utilizes a 40-VFQFN package with exposed pad for surface mount installation.

Feature Summary

• Generates up to four independent output frequencies (LVDS, LVPECL, or HCSL) from multiple input sources.
• RMS phase jitter specification below 200 fs (12 kHz to 20 MHz) for high-speed interface compliance.
• Supports boot from external I2C EEPROM or internal OTP ROM for configuration persistence.
• Integrated fractional-feedback PLL allows generation of arbitrary output frequencies from diverse inputs.

Applications

• 10 Gbps, 40 Gbps, and 100 Gbps router line cards
• Wireless access network backhaul systems
• OTU2 and OTU3 OTN multiplexers
• Xilinx Virtex UltraScale FPGA timing solutions

Procurement Notes

Verify the specific suffix '991' against official Renesas documentation to confirm the exact factory pre-programmed frequency set and boot mode. Confirm availability status as distribution channels may report limited stock or end-of-life transitions following corporate acquisitions. Ensure compatibility with the required I2C address and EEPROM configuration file before ordering.

Selection Notes

Select this component when designing for 10G/40G/100G Ethernet or SONET/SDH applications requiring low jitter performance under 200 fs. Compare against the 8T49N241 and 8T49N242 variants; note that the 8T49N240 lacks the fractional output divider found in the 8T49N241, limiting its frequency granularity compared to the newer models.

Part Context

This part belongs to the FemtoClock NG family, which provides flexible timing solutions for high-speed serial interfaces. The 8T49N240 series is designed to replace discrete clock generators and fanout buffers, reducing PCB area and system cost. Note that Renesas timing products are transitioning to SiTime, affecting long-term support and procurement channels.

Replacement Considerations

The 8T49N241-998NLGI and 8T49N242-998NLGI are direct functional upgrades within the same package footprint. The 8T49N241 adds a fractional output divider for finer frequency resolution, while the 8T49N242 supports higher output frequencies up to 1 GHz. Verify register compatibility if migrating between these variants.