LTC1545 Datasheet, PDF (10/16 Pages) Linear Technology – Software-Selectable Multiprotocol Transceiver

LTC1545
APPLICATIONS INFORMATION
GENERATOR
BALANCED
INTERCONNECTING
CABLE
LOAD
CABLE
TERMINATION
RECEIVER
A
A'
C
C'
1545 F11
Figure 11. Typical V.10 Interface
GENERATOR
BALANCED
INTERCONNECTING
CABLE
LOAD
CABLE
TERMINATION
RECEIVER
A
A'
100Ω
MIN
B
B'
C
C'
1545 F14
Figure 14. Typical V.11 Interface
I_Z
–10V
–3V
3V
3.25mA
V_Z
10V
A'
A
R1 ^LTC1344A
51.5Ω
R5
R8 _20k
6k
S1
R3
S3
S2 _124Ω
R2
51.5Ω
B'
C'
R4
B
20k
GND
LTC1543
LTC1545
R6 _RECEIVER
10k
R7
10k
1545 F15
–3.25mA
1545 F12
Figure 12. V.10 Receiver Input Impedance
Figure 15. V.11 Receiver Configuration
In V.11 mode, all switches are off except S1 inside the
LTC1344A which connects a 103Ω differential termina-
tion impedance to the cable as shown in Figure 15.
A'
A
R5
R8
6k
20k
S3
LTC1545
R6 _RECEIVER
10k
B'
B
R4
20k
R7
10k
C'
GND
1545 F13
Figure 13. V.10 Receiver Configuration
V.28 (RS232) Interface
A typical V.28 unbalanced interface is shown in Figure 16.
A V.28 single-ended generator output A with ground C is
connected to a single-ended receiver with input A' con-
nected to A, ground C' connected via the signal return
ground C.
In V.28 mode, all switches are off except S3 inside the
LTC1543/LTC1545 which connects a 6k (R8) impedance
to ground in parallel with 20k (R5) plus 10k (R6) for a
combined impedance of 5k as shown in Figure 17. The
noninverting input is disconnected inside the LTC1543/
LTC1545 receiver and connected to a TTL level reference
voltage for a 1.4V receiver trip point.
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