LTC2847_15 Datasheet, PDF (11/20 Pages) Linear Technology – Software-Selectable Multiprotocol Transceiver with Termination and 3.3V Digital Interface

APPLICATIO S I FOR ATIO
DTE
SERIAL
CONTROLLER
LTC2847
TXD
D1
TXD
SCTE
D2
SCTE
D3
DCE
LTC2847
103Ω
R3
103Ω
R2
R1
LTC2847
SERIAL
CONTROLLER
TXD
SCTE
TXC
R1
103Ω
TXC
RXC
R2
103Ω
RXC
D3
TXC
D2
RXC
RXD
R3
103Ω
RXD
D1
RXD
LTC2845
RTS
D1
RTS
DTR
D2
DTR
D3
LTC2845
R3
RTS
R2
DTR
R1
DCD
R1
DCD
DSR
R2
DSR
D3
DCD
D2
DSR
CTS
R3
CTS
D1
CTS
LL
D4
LL
R4
LL
TM
TM
R4
D4
TM
RI
RI
R5
D5
RI
RL
D5
RL
R5
RL
2847 F17
Figure 17. Complete Multiprotocol Interface in EIA530 Mode
When the cable is removed, leaving all mode pins uncon-
nected, the LTC2847/LTC2845 will enter no-cable mode.
In this mode the LTC2847/LTC2845 supply current drops
to less than 1000µA and the LTC2847/LTC2845 driver
outputs are forced into a high impedance state. At the
same time, the R2 and R3 receivers of the LTC2847 are
differentially terminated with 103Ω and the other receiv-
ers on the LTC2847 and LTC2845 are terminated with
30kΩ to ground.
Cable Termination
Traditional implementations used expensive relays to
switch resistors or required the user to change termina-
tion modules every time a new interface standard was
sn2847 2847fs
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