LTC1343 View Datasheet(PDF) - Linear Technology
Part Name
Description
MFG CO.
'LTC1343' PDF : 28 Pages View PDF
LTC1343
APPLICATIONS INFORMATION
The V.10 receiver configuration in the LTC1343 and
LTC1344 is shown in Figure 15. In V.10 mode switches S1
and S2 inside the LTC1344 and S3 inside the LTC1343 are
turned off. Switch S4 inside the LTC1343 shorts the
noninverting receiver input to ground so the B input at the
connector can be left floating. The cable termination is
then the 30k input impedance to ground of the LTC1343
V.10 receiver.
V.11 (RS422) Interface
A typical V.11 balanced interface is shown in Figure 16. A
V.11 differential generator with outputs A and B with
ground C is connected to a differential receiver with
ground C', inputs A' connected to A, B' connected to B. The
V.11 interface has a differential termination at the receiver
end that has a minimum value of 100Ω. The termination
resistor is optional in the V.11 specification, but for the
high speed clock and data lines, the termination is required
to prevent reflections from corrupting the data. The re-
A'
A
R1
LTC1344
51.5Ω
R5
R8 20k
6k
S1
R3
S3
S2 124Ω
R2
51.5Ω
B'
R4
B
20k
S4
C'
GND
LTC1343
R6 RECEIVER
10k
R7
10k
1343 F15
Figure 15. V.10 Receiver Configuration
ceiver inputs must also be compliant with the impedance
curve shown in Figure 14.
In V.11 mode, all switches are off except S1 inside the
LTC1344 which connects a 103Ω differential termination
impedance to the cable as shown in Figure 17.
V.28 (RS232) Interface
A typical V.28 unbalanced interface is shown in Figure 18.
A. V.28 single-ended generator output A with ground C is
connected to a single-ended receiver with inputs 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
LTC1343 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 19. The noninverting
input is disconnected inside the LTC1343 receiver and
connected to a TTL level reference voltage for a 1.4V
receiver trip point.
A'
A
R1
LTC1344
51.5Ω
R5
R8 20k
6k
S1
R3
S3
S2 124Ω
LTC1343
R6
10k
RECEIVER
R2
51.5Ω
B'
R7
R4
10k
B
20k
S4
C'
GND
1343 F17
Figure 17. V.11 Receiver Configuration
GENERATOR
BALANCED
INTERCONNECTING
CABLE
LOAD
CABLE
TERMINATION
RECEIVER
A
A'
100Ω
MIN
B
B'
C
C'
1343 F16
Figure 16. Typical V.11 Interface
12
GENERATOR
BALANCED
INTERCONNECTING
CABLE
LOAD
CABLE
TERMINATION
RECEIVER
A
A'
C
C'
1343 F18
Figure 18. Typical V.28 Interface
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