78Q2123S/F

Overview

The 78Q2123S/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 interfaces to Cat-5 UTP for 100BASE-TX and Cat-3 UTP for 10BASE-T via dual 1:1 isolation transformers. The component is housed in a 32-QFN (5x5 mm) or 32-TQFN package.

Feature Summary

• Integrated full-duplex operation with automatic MDI/MDI-X crossover correction
• Supports power-saving modes including chip power-down and transmit high impedance
• Includes programmable LED indicators and user-programmable interrupt pin
• Features adaptive equalizer and baseline restoration circuit for accurate data recovery

Applications

• Game consoles
• Broadband modems
• Printers
• Set top boxes
• Audio/video equipment

Procurement Notes

Verify the specific suffix against manufacturer documentation to confirm temperature rating and package type. The 'S' designation typically indicates a specific package variant such as TQFN. Ensure the ordering information matches the required commercial or industrial operating range defined in the official datasheet before procurement.

Selection Notes

Select this component for embedded systems requiring a compact 10/100 PHY solution. The integrated pulse shaper eliminates external filtering requirements. Verify compatibility with the host MAC's MII interface timing and ensure the system design accommodates the necessary dual 1:1 isolation transformers for line connectivity.

Part Context

This part belongs to the MicroPHY family of Fast Ethernet transceivers designed for low-power applications. It serves as a physical layer interface between the MAC and twisted-pair cabling. The series includes variants rated for different temperature ranges to support various environmental conditions in consumer and industrial electronics.

Replacement Considerations

The 78Q2133 is the industrial temperature rated counterpart to the commercial 78Q2123. Both share identical functional specifications and pinouts. Verify that the replacement maintains the same package footprint and electrical characteristics for direct integration.