SN75LBC777
SINGLE CHIP GEOPORT /AppleTalk TRANSCEIVER
SLLS227 – SEPTEMBER 1996
DW PACKAGE
(TOP VIEW)
Single-Chip Interface Solution for the 9-Pin
GeoPort Peripheral Data Circuit-
Terminating Equipment (DCE) for the
Intelligent Network Port
1
2
3
4
5
6
7
8
9
10
20
19
18
17
16
15
14
13
12
11
DA1
GND
V
V
EE
CC
Designed to Operate up to 4-Mbits/s Full
Duplex
C–
C+
SHDN
DZ2
DY2
GND
DEN
DA2
DY1
DY3
DA3
RB2
RY2
RB1
RA1
RY1
Single 5-V Supply Operation
10-kV ESD Protection on Bus Terminals
Backward Compatible with AppleTalk and
LocalTalk LANs
Combines Multiple Components into a
Single Chip Solution
Complements the SN75LBC776 9-Terminal
GeoPort Host Data Terminal Equipment
(DTE) Interface Device
logic diagram (positive logic)
LinBiCMOS Process Technology
description
7
DY2
DZ2
10
The SN75LBC777 is a low-power LinBiCMOS
device that incorporate the drivers and receivers
for a 9-pin GeoPort peripheral interface. GeoPort
combines hybrid EIA/TIA-422-B and EIA/
TIA-423-B drivers and receivers to transmit data
up to four-Mbit/s full duplex. GeoPort is a serial
communications standard that is intended to
replace the RS-232, AppleTalk, and printer ports
all in one connector in addition to providing
DA2
6
9
DEN
12
13
RA1
RB1
11
RY1
1
18
17
DY1
DY3
DA1
real-time
data
transfer
capability.
The
SN75LBC777 provides point-to-point connec-
tions between GeoPort-compatible devices with
data transmission rates up to 4-Mbit/s full duplex
over a 4-foot cable. Applications include connec-
tion to telephone, integrated services digital
network (ISDN), digital sound and imaging,
fax-data modems, and other traditional serial and
parallel connections. The GeoPort is backwardly
compatibletobothLocalTalkandAppleTalkLANs.
16
DA3
14
RY2
15
RB2
5
SHDN
19
While the SN75LBC777 is powered off (V
= 0)
V
CC
CC
2
Charge Pump
8
V
EE
the outputs are in a high-impedance state. When
the shutdown (SHDN) terminal is high, the charge
pump is powered down and the outputs are in a
high-impedance state. When high, the driver
enable (DEN) terminal puts the outputs of the
differential driver into a high-impedance state.
GND
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
GeoPort, LocalTalk, and AppleTalk are trademarks of Apple Computer, Incorporated.
LinBiCMOS is a trademark of Texas Instruments Incorporated.
Copyright 1996, Texas Instruments Incorporated
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of Texas Instruments
standard warranty. Production processing does not necessarily include
testing of all parameters.
1
POST OFFICE BOX 655303 • DALLAS, TEXAS 75265