KS8721B/BT
2.5V 10/100BasTX/FX MII Physical Layer Transceiver
Rev. 2.3
General Description
Operating at 2.5 volts to meet low voltage and low power
requirements, the KS8721B/BT is a 10BaseT/100BaseTX/FX
Physical Layer Transceiver, which provides an MII to transmit
and receive data. It contains the 10BaseT Physical Medium
Attachment (PMA), Physical Medium Dependent (PMD), and
Physical Coding Sub-layer (PCS) functions. Moreover, the
KS8721B/BT has on-chip 10BaseT output filtering, which
eliminates the need for external filters and allows a single
set of line magnetics to be used to meet requirements for
both 100BaseTX and 10BaseT.
The KS8721B/BT can automatically configure itself for 100
or 10 Mbps and full or half duplex operation, using on-chip
Auto-Negotiation algorithm. It is an ideal choice of physical
layer transceiver for 100BaseTX/10BaseT applications.
Data sheets and support documentation can be found on
Micrel’s web site at www.micrel.com.
Features
• Single chip 100BaseTX/100BaseFX/10BaseT physical
layer solution
• 2.5V CMOS design, power consumption <200mW (ex-
cluding output driver current )
• Fully compliant to IEEE 802.3u standard
• Supports Media Independent Interface (MII) and
Reduced MII (RMII)
• Supports 10BaseT, 100BaseTX and 100BaseFX with
Far_End_Fault Detection
• Supports power down mode and power saving mode
• 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 mode
• On-chip built-in analog front end filtering for both 100Ba-
seTX and 10BaseT
Functional Diagram
4B/5B Encoder
Scrambler
Parallel/Serial
Parallel/Serial
Manchester Encoder
MII/RMII
Registers
and
Controller
Interface
TX+
TX-
Transmitter
10/100
Pulse
Shaper
NRZ/NRZI
MLT3 Encoder
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
10BaseT
Receiver
Power
Down or
Saving
PLL
PWRDWN
Manchester Decoder
Serial/Parallel
LINK
LED
Driver
COL
FDX
SPD
XI
XO
Micrel, Inc. • 2180 Fortune Drive • San Jose, CA 95131 • USA • tel + 1 (408) 944-0800 • fax + 1 (408) 474-1000 • http://www.micrel.com
March 2006
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KS8721B/BT
Micrel, Inc.
Features
(continued)
• LED outputs for link, activity, full/half duplex, collision
and speed
• Supports back to back, FX to TX for media converter
applications
• Supports MDI/MDI-X auto crossover
• 2.5V/3.3V tolerance on I/O
• Commercial temperature range: 0°C to +70°C
• Industrial temperature range: –40°C to +85°C
• Available in 48-pin SSOP and TQFP
Ordering Information
Part Number
Standard
KS8721B
KS8721BT
—
Pb-Free
KSZ8721B
KSZ8721BT
KSZ8721BI
Temperature
0°C to +70°C
0°C to +70°C
–40°C to +85°C
Package
48-Pin SSOP
48-Pin TQFP
48-Pin SSOP
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KS8721B/BT
Micrel, Inc.
Summary of Changes
Document Origination (Preliminary)
Update timing Spec from page 33 to page 37
Change Revision ID from 1000 to 1001
Add new control register bit, Control Register 0 Bit 0, to control transmit enable/disable
Add 8h register map on the table
Editorial Change on FXSD/FXEN pin34
Change on duplex pin38 0=half and 1=full duplex
Change on the 10BT MII transmit timing 1.0us to 2.5us and Tlat 2.5us to 4BT
Add the TEST description mode on pin26
Add part number ordering information & remove pinout diagram
Edited pin description on the IO cloumn
Change the company logo, disclaimer, & contact info
Editorial changes on Stapping option description
Change on Register0h bit0, 1=disable and 0=enable
Add remote fault register4h bit13.
Add normal operating condition table & Thermal data for SSOP48 table
Add Reset Timing table & Transformer Lists
Add 48 TQFP pinout diagram & RMII AC Charateristics
Add ordering info for 48 Pin TQFP package, KS8721B/BTI industrial temperature, KSY8721B/KSY8721BT
environmentally friendly part number
Change part number from KS8721B to KS8721B/BT.
Change ordering info. from “KSY” to “KSZ” for lead free.
Change pin name from RMII_LPBK to RMII_BTB
Convert to new format.
MDIO pull-up resistor value changed to 4.7kΩ.
Added note on strapping option pins.
Updated bit 1b.0 - 1b.7 to self-clearing.
Updated Electrical Characteristic.
Updated bit 1f4:2 to resetted.
Added additional magnetics to qualified transformer.
Added reset reference circuit.
Added RMII timing specification.
Revision History
Revision
1.0
2.0
Date
2/29/02
4/01/02
2.1
1/31/03
2.2
8/29/03
2.3
1/24/04
2.3
3/16/05
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KS8721B/BT
Micrel, Inc.
Table Of Contents
Pin Description .............................................................................................................................................................6
Strapping Option...........................................................................................................................................................9
Pin Configuration
........................................................................................................................................................10
Introduction
............................................................................................................................................................ 11
100BaseTX Transmit............................................................................................................................................. 11
100BaseTX Receive ............................................................................................................................................. 11
PLL Clock Synthesizer .......................................................................................................................................... 11
Scrambler/De-scrambler (100BaseTX only) ......................................................................................................... 11
10BaseT Transmit ................................................................................................................................................. 11
10BaseT Receive .................................................................................................................................................. 11
SQE and Jabber Function (10Base only).............................................................................................................. 11
Auto-Negotiation ................................................................................................................................................... 11
MII Management Interface ....................................................................................................................................12
MII Data Interface..................................................................................................................................................12
Transmit Clock ..............................................................................................................................................12
Receive Clock ...............................................................................................................................................12
Transmit Enable ............................................................................................................................................12
Receive Data Valid ........................................................................................................................................12
Error Signals..................................................................................................................................................12
Carrier Sense ................................................................................................................................................12
Collision .........................................................................................................................................................13
RMII Signal Definition............................................................................................................................................13
Reference Clock....................................................................................................................................................13
Carrier Sense/Receive Data Valid.........................................................................................................................13
Receive Data.........................................................................................................................................................13
Transmit Enable ....................................................................................................................................................13
Transmit Data ........................................................................................................................................................14
Collision Detection ................................................................................................................................................14
RX_ER
............................................................................................................................................................14
RMII AC Characteristics ........................................................................................................................................14
Auto Crossover (Auto MDI/MDI-X) ........................................................................................................................15
Power Management ..............................................................................................................................................16
100BT FX Mode ....................................................................................................................................................16
Media Converter Option ........................................................................................................................................16
Register Map
............................................................................................................................................................17
Register 0h: Basic Conrol.....................................................................................................................................17
Register 1h: Basic Status .....................................................................................................................................18
Register 2h: PHY Identifier 1 ................................................................................................................................18
Register 3h: PHY Identifier 2 ................................................................................................................................18
Register 4h: Auto-Negotiation Advertisement.......................................................................................................18
Register 5h: Auto-Negotiation Link Partner Ability................................................................................................18
Register 6h: Auto-Negotiation Expansion.............................................................................................................19
Register 7h: Auto-Negotiation Next Page.............................................................................................................19
Register 8h: Link Partner Next Page Ability .........................................................................................................19
Register 15h: RXER Counter ............................................................................................................................... 20
Register 1bh: Interrupt Control/Status Register ................................................................................................... 20
Register 1fh: 100BaseTX PHY Controller ............................................................................................................ 20
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March 2006
KS8721B/BT
Micrel, Inc.
Absolute Maximum Ratings
.......................................................................................................................................22
Operating Ratings
.......................................................................................................................................................22
Electrical Characteristics
...........................................................................................................................................22
Timing Diagrams
.........................................................................................................................................................24
Selection of Isolation Transformers
..........................................................................................................................30
Selection of Reference Crystals
................................................................................................................................30
Package Outline and Dimensions
.............................................................................................................................31
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