LTC1344A
Software-Selectable
Cable Terminator
FEATURES
s
DESCRIPTION
The LTC
®
1344A features six software-selectable
multiprotocol cable terminators. Each terminator can be
configured as an RS422 (V.11) 100Ω minimum differen-
tial load, V.35 T-network load or an open circuit for use
with RS232 (V.28) or RS423 (V.10) transceivers that
provide their own termination. When combined with the
LTC1543 and LTC1544, the LTC1344A forms a complete
software-selectable multiprotocol serial port. A data bus
latch feature allows sharing of the select lines between
multiple interface ports.
The LTC1344A is similar to the LTC1344 except for a
difference in the Mode Selection table.
The LTC1344A is available in a 24-lead SSOP.
s
Software-Selectable Cable Termination for:
RS232 (V.28)
RS423 (V.10)
RS422 (V.11)
RS485
RS449
EIA530
EIA530-A
V.35
V.36
X.21
Outputs Won’t Load the Line with Power Off
APPLICATIONS
s
s
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Data Networking
CSU and DSU
Data Routers
, LTC and LT are registered trademarks of Linear Technology Corporation.
TYPICAL APPLICATION
DTE or DCE Multiprotocol Serial Interface with DB-25 Connector
LL
CTS
DSR
DCD
DTR
RTS
RXD
RXC
TXC
SCTE
TXD
Daisy-Chained Control Outputs
LTC1544
D4
R4
R3
R2
R1
D3
D2
D1
R3
R2
R1
LTC1543
D3
D2
D1
18
LL A (141)
13 5
CTS B
CTS A (106)
10 8
DSR B
DSR A (109)
22 6
DCD B
DCD A (107)
23 20 19 4
DTR B
DTR A (108)
RTS B
RTS A (105)
SHIELD (101)
1
SG (102)
7
16 3
RXD B
RXD A (104)
9
RXC B
17
RXC A (115)
12 15 11 24 14
SCTE B
SCTE A (113)
TXD B
TXD A (103)
TXC B
TXC A (114)
DB-25 CONNECTOR
U
U
U
LTC1344A
2
1344A TA01
1
LINER [ LINEAR TECHNOLOGY ]
