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KSZ8051MLL Physical Layer Transceiver

Micrel’s physical layer transceiver features low power consumption, high performance in a compact package

Micrel - SY88149HL Limiting Post Amplifier Micrel, Inc.'s KSZ8051series is a low-power, small package 10/100 physical (PHY) layer transceiver that provides the MII interface or the RMII interface to transmit and receive data over standard CAT-5 unshielded twisted pair (UTP) cable or fiber.

This PHY device is based on an enhanced mix-signal design and 0.13µm CMOS technology, which enable a new level of features, low power consumption, and high performance in a very compact package. It is the ideal choice for adding power-efficient 10/100 Ethernet connectivity to digital TVs, IP set-top boxes, game consoles, and industrial and automotive applications.

On-chip termination resistors and an integrated regulator simplify board layout while reducing the system BOM. The digital I/O interface supports 1.8V, 2.5V, and 3.3V voltage levels, offering flexibility in design. A suite of power-down and power-saving modes helps reduce power in various operating conditions further. This PHY device also provides patented techniques for lower EMI.

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  • Single 3.3V supply with internal 1.2V regulator and optional 3.3V, 2.5V, or 1.8V VDDIO
  • Energy detect power down when the cable is not plugged; and power down/slow oscillator mode when the device is not in use
  • Fully compliant to IEEE 802.3/802.3u standard
  • Integration of termination resistors on the chip
  • 25MHz crystal for input reference clock
  • HP Auto MDI/MDIX crossover supportRoHS Compliant
  • LinkMD® TDR-based cable diagnostics


  • Digital TVs
  • IP set-top boxes
  • Game consoles
  • IP phones
  • IP cameras
  • Network printers/projects
  • Media converters
  • Industrial control
  • Automotive


KSZ8051MLL Diagram

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Digi-Key P/N Micrel P/N Description Datasheet
576-3731-ND KSZ8051MLL TXRX PHY 10/T100 3.3V MII 48LQFP Datasheet