MAX3679AETJ2

Overview

The MAX3679AETJ2 is a low-jitter precision clock generator optimized for Ethernet networking applications. It integrates a crystal oscillator and a phase-locked loop (PLL) to synthesize high-frequency clock outputs from a 25MHz reference. The device provides three LVPECL outputs and one LVCMOS output, supporting frequencies up to 312.5MHz. Key electrical parameters include a supply voltage range of 3V to 3.6V, an operating temperature range of -40°C to +85°C, and ultra-low jitter performance of 0.36ps RMS (12kHz to 20MHz). It features excellent power-supply noise rejection and requires no external loop filter capacitors.

Feature Summary

• Integrates a 25MHz crystal oscillator and PLL with 0.36ps RMS jitter (12kHz–20MHz offset)
• Generates Ethernet-specific output frequencies: 62.5MHz, 125MHz, 156.25MHz, and 312.5MHz
• Provides three differential LVPECL outputs and one single-ended LVCMOS output
• Eliminates the need for external loop filter capacitors due to integrated low-pass filter

Applications

• Ethernet networking equipment
• Network interface controllers requiring precise clock synthesis
• Systems utilizing 25MHz crystal or CMOS reference inputs

Procurement Notes

Verify that the ordering suffix '2' corresponds to a lead-free/RoHS-compliant package as specified in the datasheet. Confirm the 32-TQFN (5x5) package with exposed pad matches the design requirements. Ensure the component meets the industrial temperature grade (-40°C to +85°C) required for the target application environment.

Selection Notes

Select this component when designing systems requiring low-jitter clock generation for Ethernet interfaces. The device supports both crystal and LVCMOS reference inputs. Note that the maximum guaranteed output frequency is 160MHz for the LVCMOS output and 320MHz for the LVPECL outputs. Ensure the power supply tolerance is within ±5% if utilizing the recommended VCCA filtering network.

Part Context

The MAX3679A is part of a family of low-jitter precision clock generators designed for network applications. The ETJ2 suffix indicates a specific package variant (32-TQFN-EP) with lead-free/RoHS compliance. The device utilizes a BiCMOS process and contains 10,780 transistors. It is manufactured by Microchip Technology, which acquired Maxim Integrated.

Replacement Considerations

Public confirmed substitute part numbers are not available in the provided documentation.