78Q2120C Datasheet, PDF (1/35 Pages) Teridian Semiconductor Corporation – 10/100BASE-TX Transceiver

78Q2120C
10/100BASE-TX
Transceiver
DATA SHEET
DESCRIPTION
The 78Q2120C is a 10BASE-T/100BASE-TX Fast
Ethernet transceiver. It includes integrated MII,
ENDECs, scrambler/descrambler, dual-speed clock
recovery, and full-featured auto-negotiation function.
The transmitter includes an on-chip pulse-shaper and
a low-power line driver. The receiver has an adaptive
equalizer and a baseline restoration circuit required
for accurate clock and data recovery. The transceiver
interfaces to Category-5 unshielded twisted pair (Cat-
5 UTP) cabling for 100BASE-TX/10BASE-T and
Category-3 unshielded twisted pair for 10BASE-T.
Connection to the line media is via 1:1 isolation
transformers. No external filter is required. Interface
to the MAC is accomplished through an IEEE-802.3
compliant Media Independent Interface (MII). The
product is fabricated in an advanced CMOS process
for high performance and low power operation.
FEATURES
January 2009
• 10BASE-T/100BASE-TX IEEE-802.3 compliant
TX and RX functions requiring a dual 1:1
isolation transformer interface to the line
• Integrated MII, 10BASE-T/100BASE-TX ENDEC,
100BASE-TX scrambler/descrambler, and full-
featured auto-negotiation function
• Full duplex operation capable
• PCS Bypass supports 5-bit symbol interface
• Register-programmable transmit amplitude
• Dual speed digital clock recovery
• Automatic polarity correction during auto-
negotiation and 10BASE-T signal reception
• Power-saving and power-down modes
including transmitter disable
• LED indicators: LINK, TX, RX, COL, 100, 10,
FDX
• User programmable Interrupt pin
• 64-Pin TQFP (JEDEC LQFP) package
• Single 3.3 V ± 0.3V Supply
BLOCK DIAGRAM
RX_CLK
TX_CLK
RXD[3:0]
TXD[3:0]
4B/5B Encoder,
100M _Scrambler,
Parallel/Serial
NRZ/NRZI
MLT3 Encoder
MII
Registers
&
Interface
Logic
10M _{Parallel/Serial,}
MMaanncchheesstteerr EEnnccooddeerr
TX CLK GEN
Carrier Sense,
Manchester Decoder,
CCoollliissiioonn DDeetteecctt
Parallel/Serial
CLK
Recovery
Serial/Parallel
Descrambler,
5B/4B Decoder CClloocckkRReeffeerreennccee
PS
PPuullssee SShhaappeerr
and Filter
TXOP/N
Auto
Negotiation
MDI
RXIP/N
10M 100M
Adaptive EQ,
Baseline Wander Correct,
MMLLTT33 DDeeccooddee,, NNRRZZII//NNRRZZ
LEDs
VCC GND
LEDL LEDBTX LEDTX LEDCOL
CKIN 25MHz
LEDBT LEDFX LEDRX
Page: 1 of 35
© 2009 Teridian Semiconductor Corporation
Rev 1.3