LTC1320
AppleTalk© Transceiver
OBSOLETE:
FOR INFORMATION PURPOSES ONLY
Contact Linear Technology for Potential Replacement
DESCRIPTIO
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FEATURES
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Single Chip Provides Complete
LocalTalk©/AppleTalk© Port
Low Power: ICC = 1.2mA Typ
Shutdown Pin Reduces ICC to 30µA Typ
Drivers Maintain High Impedance in Three-State
or with Power Off
30ns Driver Propagation Delay Typ
5ns Driver Skew Typ
Thermal Shutdown Protection
Drivers are Short-Circuit Protected
APPLICATI
The LTC1320 is an RS422/RS562 line transceiver designed to operate on LocalTalk networks. It provides one
differential RS422 driver, one single-ended RS562 driver,
two single-ended RS562 receivers, and one differential
RS422 receiver. The LTC1320 draws only 1.2mA quiescent current when active and 30µA in shutdown, making
it ideal for use in battery-powered devices and other
systems where power consumption is a primary concern.
The LTC1320 drivers are specified to drive ±2V into 100Ω.
Additionally, the driver outputs three-state when disabled,
during shutdown, or when the power is off; they maintain
high impedance even with output common-mode voltages beyond the power supply rails. Both the driver
outputs and receiver inputs are protected against ESD
damage to beyond 5kV.
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LocalTalk Peripherals
Notebook/Palmtop Computers
Battery-Powered Systems
The LTC1320 is available in the 18-pin SOL package.
AppleTalk and LocalTalk are registered trademarks of Apple Computer, Inc.
TYPICAL APPLICATI
UO
Output Waveforms
Typical LocalTalk Connection
5V
18
DATA IN
TX ENABLE
RX ENABLE
DATA OUT
SHUTDOWN
17 22Ω
22Ω
16 22Ω
100pF
22Ω
1
3
5
100pF
LTC1320
#1
11 22Ω
4
9
14
–5V
22Ω
10 22Ω
8
LocalTalk
TRANSFORMER
100pF
22Ω
100pF
DATA IN
5V/DIV
120Ω
2V/DIV
1k
1k
SIGNALS
ON LINE
2V/DIV
LTC1320 • TA01
5V/DIV
DATA OUT
(REMOTE
RECEIVER)
50ns/DIV
1
