78Q2123SR/F

Overview

The 78Q2123SR/F is a MicroPHY Fast Ethernet transceiver supporting 10BASE-T and 100BASE-TX standards. It integrates MII, ENDECs, scrambler/descrambler, dual-speed clock recovery, and auto-negotiation functions. The device operates from a single 3.3V ±0.3V supply with typical power consumption of approximately 290mW. It features an adaptive equalizer, baseline restoration circuit, on-chip pulse-shaper, and low-power line driver. The component interfaces to Cat-5 UTP for 100BASE-TX and Cat-3 UTP for 10BASE-T applications via dual 1:1 isolation transformers. It is rated for commercial temperature operation from 0°C to 70°C.

Feature Summary

• Supports 10BASE-T/100BASE-TX IEEE-802.3 compliance with integrated MII and full-featured auto-negotiation.
• Includes automatic MDI/MDI-X crossover correction and automatic polarity correction during signal reception.
• Offers multiple power-saving modes including chip power-down, receive power management, and transmitter high impedance mode.
• Features programmable LED indicators for Link and Activity status along with a user-programmable interrupt pin.

Applications

• Embedded Ethernet systems for game consoles
• Broadband modems and set-top boxes
• Printers and audio/video equipment

Procurement Notes

Verify the specific suffix 'SR/F' against official documentation to confirm package type and tape-and-reel specifications. Ensure the commercial temperature rating (0°C to 70°C) aligns with system requirements rather than the industrial variant. Confirm that the ordering information matches the exact part number provided in the manufacturer's current catalog.

Selection Notes

Select this component for designs requiring a compact footprint with integrated PHY functions. The 78Q2123 is suitable for commercial environments, whereas the 78Q2133 is required for industrial temperature ranges (-40°C to 85°C). Consider the single 3.3V supply requirement and the need for external 1:1 isolation transformers when designing the schematic.

Part Context

The 78Q2123 and 78Q2133 are part of the MicroPHY family of Fast Ethernet transceivers manufactured by Analog Devices Inc./Maxim Integrated. This series is designed to provide the smallest form factor for 10/100 Mbps Ethernet connectivity. The 78Q2123 specifically denotes the commercial temperature grade version within this product line.

Replacement Considerations

The 78Q2133 serves as the industrial temperature range equivalent. Verify compatibility if substituting between commercial and industrial grades due to temperature specification differences.