Datasheet
Table Of Contents
- 1.0 Introduction
- 2.0 Pin Description and Configuration
- 3.0 Functional Description
- 3.1 10BASE-T/100BASE-TX Transceiver
- 3.2 RMII Interface
- 3.3 Back-to-Back Mode – 100 Mbps Copper Repeater
- 3.4 MII Management (MIIM) Interface
- 3.5 Interrupt (INTRP)
- 3.6 HP Auto MDI/MDI-X
- 3.7 Loopback Mode
- 3.8 LinkMD® Cable Diagnostic
- 3.9 NAND Tree Support
- 3.10 Power Management
- 3.11 Reference Circuit for Power and Ground Connections
- 3.12 Typical Current/Power Consumption
- 4.0 Register Descriptions
- 5.0 Operational Characteristics
- 6.0 Electrical Characteristics
- 7.0 Timing Diagrams
- 8.0 Reset Circuit
- 9.0 Reference Circuits — LED Strap-In Pins
- 10.0 Reference Clock - Connection and Selection
- 11.0 Magnetic - Connection and Selection
- 12.0 Package Outline
KSZ8081RNA/RND
DS00002199A-page 4 2016 Microchip Technology Inc.
1.0 INTRODUCTION
1.1 General Description
The KSZ8081RNA/RND is a single-supply 10BASE-T/100BASE-TX Ethernet physical-layer transceiver for transmis-
sion and reception of data over standard CAT-5 unshielded twisted pair (UTP) cable.
The KSZ8081RNA/RND 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/RND 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/RND uses a 25 MHz crystal to generate all required clocks, including the
50 MHz RMII reference clock output for the MAC. The KSZ8081RND is the version that takes in the 50 MHz RMII ref-
erence clock as the power-up default.
To facilitate system bring-up and debugging in production testing and in product deployment, parametric NAND tree sup-
port enables fault detection between KSZ8081RNA/RND I/Os and the board. LinkMD
®
TDR-based cable diagnostics
identify faulty copper cabling.
The KSZ8081RNA and KSZ8081RND are available in 24-pin, lead-free QFN packages.
FIGURE 1-1: SYSTEM BLOCK DIAGRAM
KSZ8081RNA
MAGNETICS
RJ-45
CONNECTOR
MEDIA TYPES:
10BASE-T
100BASE-TX
ON-CHIP TERMINATION
RESISTORS
RMII
MDC/MDIO
MANAGEMENT
XO
XI
25MHz
XTAL
22pF
22pF
10/100Mbps
RMII MAC
50MHz
REF_CLK