LTC1343 Linear Technology, LTC1343 Datasheet - Page 12

• Manufacturer Part Number: LTC1343
• Description: Software-Selectable Multiprotocol Transceiver
• Manufacturer: Linear Technology

APPLICATIONS
LTC1343
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
V.11 interface has a differential termination at the receiver
end that has a minimum value of 100 . 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-
12
B
C
A
'
'
'
GENERATOR
R1
51.5
R2
51.5
S1
'
S2
, inputs A
Figure 15. V.10 Receiver Configuration
124
LTC1344
A
B
C
Figure 16. Typical V.11 Interface
R3
INTERCONNECTING
'
U
connected to A, B
BALANCED
CABLE
A
B
INFORMATION
U
GND
R8
6k
S3
20k
20k
R4
S4
R5
A
B
C
TERMINATION
'
'
'
W
CABLE
'
connected to B. The
100
MIN
R6
10k
R7
10k
LOAD
RECEIVER
RECEIVER
LTC1343
U
1343 F16
1343 F15
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 103 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
nected to A, ground C
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.
C
A
B
'
'
'
GENERATOR
R1
51.5
S1
R2
51.5
S2
Figure 17. V.11 Receiver Configuration
124
LTC1344
Figure 18. Typical V.28 Interface
R3
C
A
INTERCONNECTING
BALANCED
CABLE
'
A
B
connected via the signal return
GND
R8
6k
S3
20k
20k
R4
S4
C
R5
A
TERMINATION
'
'
CABLE
R6
10k
R7
10k
LOAD
RECEIVER
LTC1343
RECEIVER
1343 F18
'
1343 F17
con-