adm6996f Infineon Technologies Corporation, adm6996f Datasheet - Page 20

• Manufacturer Part Number: adm6996f
• Description: 6 Port 10/100 Mb/s Single Chip Ethernet Switch Controller
• Manufacturer: Infineon Technologies Corporation

ADM6996F
Infineon-ADMtek Co Ltd.
3.4
3.4.1 A/D Converter
3.4.2 Adaptive Equalizer and timing Recovery Module
3.4.3 NRZI/NRZ and Serial/Parallel Decoder
100Base-X Receiver
The 100Base-X receiver consists of functional blocks required to recover and condition
the 125Mbits/s receive data stream.
receiving state machine diagram as given in ANSI/IEEE Standard 802.3u, Clause 24. The
125Mbits/s receive data stream may originate from the on-chip twisted-pair transceiver in
a 100Base-TX application. Alternatively, the receive data stream may be generated by an
external optical receiver as in a 100Base-FX application.
The receiver block consists of the following functional sub-blocks:
x
x
x
x
x
x
x
x
x
A high performance A/D converter with 125Mhz sampling rate converts signals received
on RXP/RXN pins to 6 bits data streams; it also possess auto-gain-control capabilities
that will further improve receive performance especially under long cable or harsh
detrimental signal integrity. Due to high pass characteristic on transformer, built in base-
line-wander correcting circuit will cancel it out and restore its DC level.
All digital design is especially immune from noise environments and achieves better
correlation between production and system testing. Baud rate Adaptive Equalizer/Timing
Recovery compensates line loss induced from twisted pair and tracks far end clock at
125M samples per second. Adaptive Equalizer implemented with Feed forward and
Decision Feedback techniques meet the requirement of BER less than 10-12 for
transmission on CAT5 twisted pair cable ranging from 0 to 120 meters.
The recovered data is converted from NRZI to NRZ. The data is not necessarily aligned
to 4B/5B code group’s boundary.
A/D Converter
Adaptive Equalizer and timing recovery module
NRZI/NRZ and serial/parallel decoder
De-scrambler
Symbol alignment block
Symbol Decoder
Collision Detect Block
Carrier sense Block
Stream decoder block
The ADM6996F implements the 100Base-X
Function Description
3-2