INDEX
MX98702
FEATURE
* Compatible with ANSI X3T9.5 TP-PMD draft standard
* Compatible with ANSI IEEE 802.3 100 Base-T fast ethernet draft standard
* Integrated trans mitter and receiver with adaptive equalizer
* Programmable NRZI and MLT3 selection
* Programmable full equalization, normal equalization and equalization
* Isolated digital and analog power supply to minimize the power and ground noise
* Controlled transmit output slew rates to reduce EMI
* Tri-state control of transmit output current
* Loop back control for board diagnostics
* Single 5 Volts supply
* 28-pin PLCC
100BASE-TX PMD TRANSCEIVER
GENERAL DESCRIPTION
The MX98702 100Base-TX PMD transceiver is an integrated circuitcapable of transmitting and receiveing of
125 Mbaud three level (MLT-3) encoded datastream. it allows links of up to 100 meters of UTP (Unshielded
Twisted paired cable) (over Category 5) and STP (Shielded Twisted paired cable).
PIN CONFIGURATION
VDD
REF
TGND
TON
TOP
TGND
TVDD
5
6
7
8
9
10
11
MX98702
28-PIN PQFP
25
24
23
22
21
20
19
ROP
RON
EVDD
GND
SDN
SDD
LBC
P/N:PM0361
REV.1.1, MAY. 31, 1996
1
INDEX
MX98702
FUNCTIONAL BLOCK DIAGRAM
TXI
MLT-3 Encoder
Output Driver
TXO
SDO
RXO
Loopback Control
MLT-3/NRZI
detector
Adaptive Equalizer
RXI
EQS
2
INDEX
MX98702
PIN DESCRIPTION
SIGNAL
RIN
RIP
RGND
RVDD
VDD
REF
TGND
TON
TOP
TGND
TVDD
ENCS
VDD
GND
TIP
TIN
EQS
OEB
LBC
SDP
SDN
GND
EVDD
RON
ROP
VDD
RVDD
RGND
PIN
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
PIN TYPE
IN
IN
GND
VDD
VDD
OUT
GND
OUT
OUT
GND
VDD
IN
VDD
GND
IN
IN
IN
IN
IN
OUT
OUT
GND
VDD
OUT
OUT
VDD
VDD
GND
DESCRIPTION
Receive negative input, differential voltage in.
Receive positive input, differential voltage in.
Receive ground.
Receive VDD.
Transmit VDD.
A current output pin connected to a reference register.
Transmit ground.
Transmit negative output.
Transmit positive output.
Transmit ground.
Transmit VDD.
Encoder select.
Power supply.
Ground.
Transmit positive PECL input.
Transmit negative PECL input.
Equalization select.
Output enable.
Loopback control.
Signal detect positive output, ECL output.
Signal detect negative output, ECL output.
Ground.
External power supply.
Receive negative output, ECL output.
Receive positive output, ECL output.
Power supply.
Receive VDD.
Receive ground.
3
INDEX
MX98702
FUNCTIONAL DESCRIPTION
The TON and TOP are generated from the input of TIP and TIN through the MLT-3 encoder. The outputs are
either XRZI or MLT3 waveform depending on the input of ENCS. When ENCS is low the TON and TOP are
NRZI outputs. When ENCS is high the TON and TOP are MLT-3 outputs.
The EQS will provide the choice of equalization. If pin EQS is over 2/3 of VDD, the equalization function is turn
off. If it is below 1/3 of VDD, there will be a equalization for maximum length.
After the receive inputs are equalizated, they will go ahead to the MLT-3/NRZI decoder, and then the Lookback
control block. Finally, the RON and ROP with PECL level come out off the chip.
SDP and SDN are generates to indicat that either a valid signal is present at RIN and RIP inputs or that
loopback mode has been selected.
SDP and SD are also PECL level.
A voltage to current converter are integrated in the chip. The converter provides the reference current for
transmit output. The current can be controlled through an external register which is connected to the REF pin.
ABSOLUTE MAXIMUM RATINGS
Logic Power Referenced to GND
Received Power Referenced to RGND
Transmit Power Referenced to TGND
ECL output Power Referenced to GND
DC output current (High)
ESD
Storage Temperature
-6.5
-0.5V to +0.7V
-0.5V to +0.7V
-0.5V to +0.7V
-0.5V to +0.7V
-50mA
TBD
to +150
4
INDEX
MX98702
DC ELECTRICAL CHARACTERISTIC TA=25
SYMBOL
VIHt
VILt
VIHschmitt
VILschmitt
VIHeqsel
VILeqsel
VIMeqsel
VIHe
VILe
VOHe
VOLe
ICC1
ICCT
ITXO1
ITXO2
SDTHon
SDTHoff
PARAMETER
TTL High Level Input
TTL Low Level Input
Schmitt High Level Input
Schmitt Low Level Input
EQSEL High Level Input
EQSEL Low Level Input
EQSEL Mid Level Input
ECL High Level Input
ECL Low Level Input
ECL High Level Output
ECL Low Level Output
Partial Supply Current
Total Supply Currit
Transmit Current 1
Transmit Current 2
Sig Det Turn-on Threshold
Sig Det Turn-off Threshold
Note 1
Note 1
Note 1
Note 1
Transmit Current/50 ohm Zo
Transmit Current/75 ohm Zo
900
750
Vcc-1165
Vcc-1810
Vcc-1025
Vcc-1810
90
145
TBD
TBD
Vcc/2
Vcc-880
Vcc-1475
Vcc-880
Vcc-1620
3.7
1.5
3.7
1.5
CONDITIONS
MIN
2.0
0.8
TYP
MAX
UNITS
V
V
V
V
V
V
V
mV
mV
mV
mV
mA
mA
mA
mA
mV
mV
5
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