251MLF

Overview

The 251MLF is a field-programmable spread spectrum clock synthesizer from the VersaClock family, manufactured by Renesas Electronics. It operates on a single 3.3V supply and utilizes an internal Phase-Locked Loop (PLL) to generate output frequencies up to 200 MHz from input clocks ranging from 3 to 150 MHz. The device features four addressable configuration registers and One-Time Programmable (OTP) ROM for field programmability. It supports configurable spread spectrum modulation to reduce electromagnetic interference and includes a power-down feature that tri-states outputs when activated.

Feature Summary

• Field-programmable architecture with OTP ROM and four selectable configuration registers
• Output frequency range of 314 kHz to 200 MHz using PLL techniques
• Configurable spread spectrum modulation for EMI reduction
• Power-down mode that disables PLLs and tri-states outputs via PDTS pin

Applications

• Replacing multiple discrete crystals and oscillators in system designs
• Generating low-EMI clock signals for digital systems
• Providing programmable clock sources for embedded applications

Procurement Notes

Verify component status as the 251MLF series may be obsolete or subject to discontinuation notices. Confirm package type availability, typically 8-pin SOIC, and check for specific suffix variations such as PMILF or PMLF which denote temperature ranges. Ensure compatibility with required programming tools like VersaClock software before procurement.

Selection Notes

Select this component for applications requiring a single-output programmable clock generator with spread spectrum capabilities. Verify that the input crystal frequency falls within the 5 to 27 MHz range and that the required output does not exceed 200 MHz. Consider the operating temperature range (-40°C to 85°C for industrial variants) and ensure the 3.3V supply voltage aligns with system requirements.

Part Context

The 251MLF belongs to the VersaClock family of clock synthesizers, originally developed by Integrated Device Technology (IDT) and now part of Renesas Electronics. This series is designed to simplify clock generation by integrating PLL functionality into a small surface-mount package, reducing board space compared to discrete oscillator solutions.

Replacement Considerations

Publicly confirmed substitute part numbers include the 5P35021 VersaClock 3S Programmable Clock Generator. Verify functional equivalence regarding pinout, voltage levels, and programmability features before substitution.