LTC1318 Datasheet, PDF (1/8 Pages) Linear Technology – Single 5V RS232/RS422/AppleTalk DCE Transceiver

LTC1318
Single 5V
RS232/RS422/AppleTalk^®
DCE Transceiver
FEATURES
s _{Single Chip Provides DCE RS232 or}
RS422/AppleTalk DCE Port
s _{Operates from a Single 5V Supply}
s _{Charge Pump Uses 0.1µF Capacitors}
s _{Output Common-Mode Voltage Range Exceeds}
Power Supply Rails for All Drivers
s _{Driver Outputs Are High Impedance with Power Off}
s _{Pin Selectable RS232/RS422 Receiver}
s _{Thermal Shutdown Protection}
s _{Drivers Are Short-Circuit Protected}
APPLICATIONS
s _{Dual-Mode RS232/RS422 Peripherals}
s _{AppleTalk Peripherals}
s _{Single 5V Systems}
DESCRIPTION
The LTC^®1318 is a single 5V, RS232/RS422 transceiver
for connection to the DCE, or peripheral side of an interface
link. It includes an on-board charge pump to generate a
±8V supply which allows true RS232 output swings. The
charge pump requires only four external 0.1µF capacitors.
The LTC1318 includes two RS232 drivers, a differential
RS422 driver, a dedicated RS232 receiver, and a pin
selectable RS232/RS422 receiver which can receive either
single-ended or differential signals.
The LTC1318 features driver outputs which can be taken
to common-mode voltages outside the power supply rails
without damage. Additionally, the driver outputs assume
a high impedance state when the power is shut off,
preventing externally applied signals from feeding back
into the power supplies. The RS232 devices will operate at
speeds up to 100kbaud. The RS422 devices will operate
up to 2Mbaud.
The LTC1318 is available in a 24-lead SO Wide package.
, LTC and LT are registered trademarks of Linear Technology Corporation.
AppleTalk and LocalTalk are registered trademarks of Apple Computer, Inc.
TYPICAL APPLICATIONS
V⁺
0.1µF
C1⁺
0.1µF
C1^–
CHARGE
PUMP
RS232
LINES
RXI1 RS232
TXO1 RS232
TXO2 RS232
APPLETALK
NETWORK
1k 22Ω
1k 22Ω
22Ω
22Ω
5V ^VCC
22Ω
R X D ⁺ RS422
R X D ^–/RXI2
22Ω
TXD⁺
RS232
T X D ^– RS422
22Ω
NC
LTC1318
22Ω
LOCALTALK^®
TRANSFORMER
100pF × 4
V^–
C2^–
C2⁺
0.1µF
RXO1
TXI1
TXI2
GND
RXDO/RXO2
TXD
RXMODE
GND
NC
0.1µF
TXD
(5V/DIV)
Driver Output Waveforms
TO
DIGITAL
SYSTEM
TXD⁺, TXD^–
(2V/DIV)
RXDO
(5V/DIV)
R_L = 100Ω
C_L = 100pF
200ns/DIV
1318 TA02
LT1318 • TA01
1