FINAL
Publication# 14395 Rev: D Amendment/0
Issue Date: May 1994
1
Am79C98
Twisted-Pair Ethernet Transceiver (TPEX)
DISTINCTIVE CHARACTERISTICS
s
CMOS device provides compliant operation and
low operating current from a single +5 V supply
s
Power Down mode provides reduced power
consumption for battery-powered applications.
Reset capability allows use in remote MAU
applications.
s
Pin-selectable twisted-pair receive polarity
detection and automatic inversion of the receive
signal. Polarity indication output pin can
directly drive an LED.
s
Pin-selectable twisted-pair Link Integrity Test
capability conforming to the IEEE 802.3
standard for 10BASE-T. Link status pin can
directly drive an LED.
s
Internal twisted-pair transmitter digital
predistortion circuit reduces medium-induced
jitter and ensures compliance with the
10BASE-T transmit and receive waveform
requirements
s
Pin-selectable SQE Test (heartbeat) enable
s
Transmit and receive status indications are
available on separate, dedicated pins
s
AUI loopback, Jabber Control, and SQE Test
functions comply with the 10BASE-T standard
IEEE Std 802.3i-1990
GENERAL DESCRIPTION
The Am79C98 Twisted-Pair Ethernet Transceiver
(TPEX) is an integrated circuit that implements the
medium attachment unit (MAU) functions for the
twisted-pair medium, as specified by the IEEE 802.3
standard (Type 10BASE-T). This device provides the
necessary electrical and functional interface between
the IEEE 802.3 standard attachment unit interface
(AUI) and the twisted-pair cable.
A network based on the 10BASE-T standard can use
unshielded twisted-pair cables, providing an economi-
cal solution to networking by allowing the use of exist-
ing telephone wiring. The Am79C98 provides a minimal
component count and cost-effective solution to the
design and implementation of 10BASE-T standard
networks.
TPEX provides twisted-pair driver and receiver circuits,
including on-board transmit digital predistortion, re-
ceiver squelch, and an AUI port with pin-selectable
SQE Test enable. The device also provides a number of
additional features, including pin-selectable Twisted-
Pair Receive Polarity Detection and Automatic Polarity
Reversal, Link Status indication, Link Test disable func-
tion, and transmit and receive status. The Twisted-Pair
Polarity and Link Status pins can be used to drive LEDs
directly.
The Am79C98 is fabricated in CMOS technology and
requires a single +5 V supply. The device is available in
24-pin SKINNYDIP
plastic dual in-line and 28-pin
plastic leaded chip carrier (PLCC) packaging.
AMD
3
Am79C98
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CONNECTION DIAGRAM
Top View
14395D-2
DIP
Note:
Pin 1 is marked for orientation
PLCC
14395D-3
1
2
24
23
3
4
5
22
21
20
6
7
8
19
18
17
9
10
11
16
15
14
12 13
RCV
RXPOL
RXD
RXD+
SQE^TEST
TEST
TXP
TXP+
TXD
TXD+
DV
DD
AV
DD
CI+
CI
DI+
DI
XMT
LNKST
DO+
DO
PRDN/RST
REXT
DV
SS
AV
SS
1
3
2
4
5
6
7
8
9
10
11
25
24
23
22
21
20
19
28 27 26
15
13 14
12 16 17 18
DV
SS
DV
SS
XMT
LNKST
AV
SS
AV
SS
DO+
TXP
DV
DD
TEST
SQE^TEST
AV
DD
DI
DI+
CI
CI+
TXD+
RCV
DO
PRDN/RST
RXD+
TXD
TXP+
DV
DD
RXPOL
RXD
REXT
AV
DD
Am79C98 5
ORDERING INFORMATION
Standard Products
AMD standard products are available in several packages and operating ranges. The order number (valid combination) is formed
by a combination of the elements below.
Valid Combinations
Valid combinations list configurations planned to be sup-
ported in volume for this device. Consult the local AMD sales
office to confirm availability of specific valid combinations and
to check on newly released combinations.
AM79C98
DEVICE NUMBER/DESCRIPTION
Am79C98
Twisted-Pair Ethernet Transceiver (TPEX)
OPTIONAL PROCESSING
Blank = Standard Processing
TECHNOLOGY
C = CMOS Electrically Erasable
PACKAGE TYPE
P = 24-Pin Plastic DIP (PD 3024)
J = 28-Pin Plastic Leaded Chip Carrier (PL 028)
SPEED
Not Applicable
Valid Combinations
AM79C98 PC, JC
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