www.micrel.com
KS8721BL/SL
Product Brief
3.3V 10/100BASE-TX/FX Physical Layer Transceiver
Description
The KS8721BL/SL is a 10BASE-T, 100BASE-TX, and
100BASE-FX physical layer transceiver providing MII/
RMII interfaces to MACs and switches. Using a unique
mixed-signal design that extends signaling distance while
reducing power consumption, the KS8721BL/SL repre-
sents Micrel’s fourth generation single-port Fast Ethernet
PHY.
Micrel’s architecture dissipates an ultra-low 275mW in
power, including transmit output drivers. This translates to
increased reliability while enabling deployment in today’s
’s
power-sensitive applications. Multiple power-down modes,
accessed via configuration pins or registers, allow further
levels of power saving through manual selection or auto-
matic detection of cable energy.
The KS8721BL/SL automatically configures itself for
100Mbps or 10Mbps and full- or half-duplex operation,
using an on-chip auto-negotiation algorithm. Combined
with Auto MDI/MDIX for automatic correction and detec-
tion of crossover and straight-through cables, the
KS8721BL/SL provides an easy-to-use, high performance
solution for 10BASE-T, 100BASE-TX, and 100BASE-FX
applications.
For additional information, contact your local Micrel Field
Application Engineer or salesperson.
Block Diagram
NRZ/NRZI
MLT3 Encoder
4B/5B Encoder
Scrambler
Parallel/Serial
TXD3
TXD2
TXD1
TXD0
TXER
TXC
TXEN
CRS
COL
MDIO
MDC
RXD3
RXD2
RXD1
RXD0
RXER
RXDV
RXC
TX+
TX–
Transmitter
10/100
Pulse
Shaper
Parallel/Serial
Manchester Encoder
MII/RMII
Registers
and
Controller
Interface
RX+
RX–
Adaptive EQ
Baseline Wander
Correction
MLT3 Decoder
NRZI/NRZ
Clock
Recovery
4B/5B Decoder
Descrambler
Serial/Parallel
Auto
Negotiation
Manchester Decoder
Serial/Parallel
10BASE-T
Receiver
Power-Down/
Power-Saving
XI
XO
PLL
PWRDWN
LED
Driver
LINK
COL
FDX
SPD
Micrel Semiconductor
TEL:
1.408.944.0800
FAX:
1.408.474.1000
HTTP://
www.micrel.com
MICREL [ MICREL SEMICONDUCTOR ]
