MC100H646FNR2

Clock Buffers, Drivers Overview

The MC100H646FNR2 is a clock distribution integrated circuit manufactured by onsemi, designed for high-speed signal routing in digital systems. It operates as a fan-out buffer with a 2:8 input-to-output ratio, accepting differential ECL or TTL inputs and providing single-ended TTL outputs. The device supports maximum frequencies up to 80 MHz and functions within a supply voltage range of 4.75V to 5.25V. Packaged in a 28-LCC (J-lead) surface-mount housing, it is intended for applications requiring precise clock timing, such as those involving 68030 or 68040 microprocessors. The component is currently classified as obsolete.

Clock Buffers, Drivers Feature Summary

• 2:8 Input/Output Ratio: Converts two differential input signals into eight single-ended output channels.
• High-Speed Operation: Supports clock frequencies up to 80 MHz with low skew characteristics.
• Flexible Input Compatibility: Accepts both ECL and TTL logic levels at the input stage.
• TTL Output Stage: Provides robust single-ended TTL outputs suitable for driving standard logic loads.

Clock Buffers, Drivers Applications

• Clock distribution networks for 68030 and 68040 microprocessors.
• System-level clock buffering in high-performance computing architectures.
• Frequency generation and distribution in industrial control systems.

Clock Buffers, Drivers Procurement Notes

This part number is officially marked as obsolete by the manufacturer. Availability is limited to surplus stock held by third-party distributors such as Rochester Electronics. Verification of lot date codes and storage history is critical due to the component's discontinued status. Buyers should confirm authenticity through authorized surplus channels rather than primary manufacturing lines.

Clock Buffers, Drivers Selection Notes

Engineers replacing this component must account for its 80 MHz frequency limit and 2:8 fan-out structure. If higher speeds are required, the MC10H646 variant offers similar functionality but may differ in specific electrical parameters. Ensure that the target PCB layout accommodates the 28-LCC package dimensions and that the power supply provides stable 5V regulation within the specified tolerance.

Clock Buffers, Drivers Part Context

The MC100H646FNR2 belongs to the MC100H series of clock drivers from onsemi, which are optimized for ECL-to-TTL translation. This series was widely used in legacy computer systems and telecommunications equipment during the era of 68k-based processors. The 'FNR2' suffix indicates the specific tape-and-reel packaging configuration for automated assembly.

Clock Buffers, Drivers Replacement Considerations

Direct pin-compatible replacements are scarce due to obsolescence. The MC10H646FNR2 is a related model within the same family but requires verification of electrical parameter compatibility. System designers should evaluate modern low-power clock buffers if migrating to newer process technologies.