KS8721BL/SL
Micrel
KS8721BL/SL
3.3V Single Power Supply 10/100BASE-TX/FX MII Physical Layer Transceiver
Rev. 1.1
General Description
Operating with a 2.5V core to meet low-voltage and low-
power requirements, the KS8721BL and KS8721SL are
10BASE-T/100BASE-TX/FX Physical Layer Transceivers
that use MII and RMII interfaces to transmit and receive data.
They contain 10BASE-T Physical Medium Attachment (PMA),
Physical Medium Dependent (PMD), and Physical Coding
Sub-layer (PCS) functions. The KS8721BL/SL also have on-
chip 10BASE-T output filtering. This eliminates the need for
external filters and allows a single set of line magnetics to be
used to meet requirements for both 100BASE-TX and
10BASE-T.
The KS8721BL/SL automatically configures itself for 100 or
10Mbps and full- or half-duplex operation, using an on-chip
auto-negotiation algorithm. It is the ideal physical layer
transceiver for 100BASE-TX/10BASE-T applications.
Features
• Single chip 100BASE-TX/100BASE-FX/10BASE-T
physical layer solution
• 2.5V CMOS design; 2.5/3.3V tolerance on I/O
• 3.3V single power supply with built-in voltage regulator;
Power consumption <340mW (including output driver
current)
• Fully compliant to IEEE 802.3u standard
• Supports MII and Reduced MII (RMII)
• Supports 10BASE-T, 100BASE-TX, and 100BASE-FX
with Far_End_Fault Detection
• Supports power-down and power-saving modes
• Configurable through MII serial management ports or via
external control pins
• Supports auto-negotiation and manual selection for
10/100Mbps speed and full-/half-duplex modes
• On-chip, built-in, analog front-end filtering for both
100BASE-TX and 10BASE-T
Functional Diagram
NRZ/NRZI
MLT3 Encoder
4B/5B Encoder
Scrambler
Parallel/Serial
Parallel/Serial
Manchester Encoder
MII/RMII
Registers
and
Controller
Interface
TX+
TX-
Transmitter
10/100
Pulse
Shaper
TXD3
TXD2
TXD1
TXD0
TXER
TXC
TXEN
CRS
COL
MDIO
MDC
RXD3
RXD2
RXD1
RXD0
RXER
RXDV
RXC
RX+
RX-
Adaptive EQ
Base Line
Wander Correction
MLT3 Decoder
NRZI/NRZ
Clock
Recovery
4B/5B Decoder
Descrambler
Serial/Parallel
Auto
Negotiation
10BASE-T
Receiver
Power
Down or
Saving
XI
XO
PLL
PWRDWN
Manchester Decoder
Serial/Parallel
LINK
LED
Driver
COL
FDX
SPD
Micrel, Inc. • 1849 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
May 2004
1
M9999-051704
MICREL [ MICREL SEMICONDUCTOR ]
