SM840002KA-TR

Application Specific Clock/Timing Overview

The SM840002KA-TR is a dual-output LVCMOS clock frequency synthesizer from the ClockWorks™ family, designed for Gigabit and 10-Gigabit Ethernet applications. It utilizes a patented RotaryWave® architecture to generate low-noise timing signals at 62.5MHz, 125MHz, or 156.25MHz using a 25MHz crystal reference. The device supports 2.5V or 3.3V supply voltages with typical phase jitter of 64 fs at 156.25MHz (1.875MHz–20MHz). It operates within an ambient temperature range of –40°C to +75°C and is housed in a 16-pin TSSOP package.

Application Specific Clock/Timing Feature Summary

• Generates two LVCMOS output pairs with maximum output skew of 12ps
• Supports core/output supply modes of 3.3V/3.3V or 2.5V/2.5V
• Typical RMS phase jitter of 64 fs at 156.25MHz (1.875MHz–20MHz)
• Configurable via F_SEL pins for 62.5MHz, 125MHz, or 156.25MHz outputs

Application Specific Clock/Timing Applications

• Gigabit Ethernet systems
• 10-Gigabit Ethernet systems

Application Specific Clock/Timing Procurement Notes

Verify that the ordering suffix 'TR' corresponds to the Tape and Reel packaging format as specified in the manufacturer's documentation. Confirm compliance with Green, RoHS, and PFOS standards required for the specific procurement batch. Ensure the operating voltage matches the selected supply mode configuration.

Application Specific Clock/Timing Selection Notes

Select this component when low-jitter LVCMOS clocks are required for Ethernet interfaces. Verify that the system design accommodates the 25MHz crystal reference input. Check that the power supply rails align with the supported 2.5V or 3.3V options. Ensure the thermal environment remains within the –40°C to +75°C operating range.

Application Specific Clock/Timing Part Context

This part belongs to the ClockWorks™ family of devices originally developed by Micrel, Inc., which has since been acquired by Microchip Technology. The device serves as a direct replacement for IDT FemtoClocks®, offering improved waveform integrity and jitter performance for high-speed networking equipment.

Application Specific Clock/Timing Replacement Considerations

The datasheet identifies the SM840002 as an excellent replacement for IDT FemtoClocks® devices.