8T49N105A-000NLGI

Overview

The Renesas Electronics 8T49N105A-000NLGI is a FemtoClock NG Universal Frequency Translator/Synthesizer. It generates output frequencies from 0.98MHz to 1300MHz using a single differential input (LVPECL, LVDS, LVHSTL, HCSL) or crystal source. The device supports three modes: Frequency Synthesizer, High-Bandwidth Frequency Translator, and Low-Bandwidth Frequency Translator. It features two factory-programmable OTP configurations selectable via the CONFIG pin or I2C register. Key electrical parameters include an input frequency range of 8kHz–710MHz, supply voltages of 2.5V or 3.3V for VCC/VCCA/VCCO, and an operating temperature of -40°C to 85°C. Typical RMS phase jitter is 439fs at 155.52MHz (Low Bandwidth Mode) and 285fs at 400MHz (Synthesizer Mode).

Feature Summary

• Fourth-generation FemtoClock NG technology with zero ppm frequency translation capability.
• Single differential output pair (Q, nQ) programmable as LVDS or LVPECL.
• Two factory-programmed One-Time Programmable (OTP) default configurations for power-up states.
• I2C serial interface for register programming and post-power-up configuration overwriting.

Applications

• Networking and communications line cards requiring precise clock translation.
• PCI Express and computing applications utilizing high-bandwidth frequency translation.
• General purpose clock generation from fundamental mode crystals.

Procurement Notes

Verify the specific ordering suffix '000' against the manufacturer's current datasheet to confirm package type and lead-free status. Confirm that the device meets RoHS 6 compliance requirements for the target assembly process. Check for any Product Change Notices (PCN) related to the IDT/Renesas transition that may affect marking or documentation.

Selection Notes

Select this component when a single-output low-phase noise translator is required. Ensure the application utilizes either the 8kHz–710MHz input range for translation or the 16MHz–40MHz crystal range for synthesis. Verify that the I2C address bits S_A0 and S_A1 can be configured to avoid bus conflicts if multiple devices are present.

Part Context

This part belongs to the IDT8T49N105I family, now under Renesas Electronics following the acquisition of Integrated Device Technology. It is a single-output variant within the FemtoClock NG Universal Frequency Translator lineup, distinct from multi-output models like the 8T49N242 or 8T49N488.

Replacement Considerations

Direct replacements must match the 40-lead VFQFN (6mm x 6mm) package and single LVDS/LVPECL output configuration. Verify compatibility of the OTP programming requirements if migrating from legacy IDT stock to current Renesas production runs.

FAQ

How are the two default power-up configurations selected?

Selection is determined by the state of the CONFIG pin or the CONFIG register bit (CFG_PIN_REG setting). A logic low selects Configuration 0, while a logic high selects Configuration 1.

What is the function of the HOLDOVER output pin?

The HOLDOVER pin indicates if the device is not locked to a valid input reference clock. It asserts high when the device enters holdover or free-run state due to loss of the input reference.

Can the factory-programmed configurations be changed after installation?

Yes, the settings can be overwritten after power-up via the I2C interface. However, these changes are volatile and will be lost upon power-down unless re-written.