KSZ8081RNACA-TR Datasheet, PDF (1/51 Pages) Micrel Semiconductor – 10Base-T/100Base-TX PHY with RMII Support

KSZ8081RNA/KSZ8081RND
10Base-T/100Base-TX PHY
with RMII Support
Revision 1.1
General Description
The KSZ8081RNA is a single-supply 10Base-T/100Base-
TX Ethernet physical-layer transceiver for transmission
and reception of data over standard CAT-5 unshielded
twisted pair (UTP) cable.
The KSZ8081RNA is a highly-integrated PHY solution. It
reduces board cost and simplifies board layout by using on-
chip termination resistors for the differential pairs and by
integrating a low-noise regulator to supply the 1.2V core, and
by offering 1.8/2.5/3.3V digital I/O interface support.
The KSZ8081RNA offers the Reduced Media Independent
Interface (RMII) for direct connection to RMII-compliant
MACs in Ethernet processors and switches.
As the power-up default, the KSZ8081RNA uses a 25MHz
crystal to generate all required clocks, including the
50MHz RMII reference clock output for the MAC. The
KSZ8081RND is the version that takes in the 50MHz RMII
reference clock as the power-up default.
To facilitate system bring-up and debugging in production
testing and in product deployment, parametric NAND tree
support enables fault detection between KSZ8081RNA
I/Os and the board. Micrel’s LinkMD^® TDR-based cable
diagnostics identify faulty copper cabling.
The KSZ8081RNA and KSZ8081RND are available in 24-
pin, lead-free QFN packages (see “Ordering Information”).
Data sheets and support documentation are available on
Micrel’s web site at: www.micrel.com.
Features
• Single-chip 10Base-T/100Base-TX IEEE 802.3
compliant Ethernet transceiver
• RMII v1.2 Interface support with a 50MHz reference
clock output to MAC, and an option to input a 50MHz
reference clock
• RMII back-to-back mode support for a 100Mbps copper
repeater
• MDC/MDIO management interface for PHY register
configuration
• Programmable interrupt output
• LED outputs for link and activity status indication
• On-chip termination resistors for the differential pairs
• Baseline wander correction
• HP Auto MDI/MDI-X to reliably detect and correct
straight-through and crossover cable connections with
disable and enable option
• Auto-negotiation to automatically select the highest link-
up speed (10/100Mbps) and duplex (half/full)
• Power-down and power-saving modes
• LinkMD TDR-based cable diagnostics to identify faulty
copper cabling
• Parametric NAND Tree support for fault detection
between chip I/Os and the board
Functional Diagram
LinkMD is a registered trademark of Micrel, Inc.
Micrel Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel [phone] • fax + 1 [phone] • http://www.micrel.com
February 6, 2014
Revision 1.1