LTC1344CG#PBF Linear Technology, LTC1344CG#PBF Datasheet - Page 8

• Manufacturer Part Number: LTC1344CG#PBF
• Description: IC CABLE TERM MULTIPROTCL 24SSOP
• Manufacturer: Linear Technology
• Type: Cabler

Specifications of LTC1344CG#PBF

• Number Of Terminations: 6
• Voltage - Supply: 4.75 V ~ 5.25 V
• Operating Temperature: 0°C ~ 70°C
• Mounting Type: Surface Mount
• Package / Case: 24-SSOP
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

APPLICATIONS
LTC1344
low side. However, all of Linear Technology’s V.35 receiv-
ers meet the RS485 input impedance specification as
shown in Figure 11, which insures compliance with the
V.35 specification when used with the LTC1344.
The generator differential impedance must be 50
150
8
Z
and the impedance between shorted terminals A
GENERATOR
Figure 11. V.35 Receiver Using the LTC1344
A
B
C
50
50
ON
S1
–0.8mA
Figure 10. Typical V.35 Interface
125
51.5
51.5
–7V
ON
U
S2
INTERCONNECTING
A
B
C
124
LTC1344
BALANCED
INFORMATION
CABLE
U
–3V
I
Z
B
C
A
'
'
'
3V
TERMINATION
W
125
Z
Z
CABLE
RECEIVER
V.35
50
50
LOAD
12V
RECEIVER
1mA
V
U
Z
1344 F11
1344 F10
to
and B to ground C must be 150
termination, switches S1 and S2 are both on and the top
side of the center resistor is brought out to a pin so it can
be bypassed with an external capacitor to reduce common
mode noise as shown in Figure 12.
Any mismatch in the driver rise and fall times or skew in
the driver propagation delays will force current through
the center termination resistor to ground causing a high
frequency common mode spike on the A and B terminals.
The common mode spike can cause EMI problems that are
reduced by capacitor C1 which shunts much of the com-
mon mode energy to ground rather than down the cable.
The LATCH Pin
The LATCH pin (21) allows the select lines (M0, M1, M2
and DCE/DTE) to be shared with multiple LTC1344s, each
with its own LATCH signal. When the LATCH pin is held
low the select line input buffers are transparent. When the
LATCH pin is pulled high, the select line input buffers latch
the state of the Select pins so that changes on the select
lines are ignored until LATCH is pulled low again. If the
latch feature is not used, the LATCH pin should be tied to
ground.
Figure 12. V.35 Driver Using the LTC1344
DRIVER
V.35
LTC1344
124
15 . For the generator
51.5
C1
100pF
51.5
ON
S2
S1
ON
1344 F12
A
B
C