Datasheet

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APPLICATION INFORMATION
V
DD
V
SS
±15 V
Output
V
DD
V
SS
SN75185 SN75185
11
12
13
14
15
16
17
18
19
20
GND
RY5
DA3
RY4
DA2
DA1
RY3
RY2
RY1
V
CC
V
SS
RA5
DY3
RA4
DY2
DY1
RA3
RA2
RA1
V
DD
10
9
8
7
6
5
4
3
2
1
43
37
40
13
36
11
41
42
RI
DTR
CTS
SO
RTS
SI
DSR
DCD
R1
DTR
CTS
TX
RTS
RX
DSR
DCD
SN75185
5 V
TL16C450
ACE
1
5
6
9
12 V
−12 V
TIA/EIA-232-F
DB9S
Connector
C1
(1)
C3
(1)
C2
(1)
SN75185
MULTIPLE RS-232 DRIVERS AND RECEIVERS
SLLS181D–DECEMBER 1994 – REVISED JANUARY 2006
Diodes placed in series with the V
DD
and V
SS
leads protect the SN75185 in the fault condition. In the fault
condition, the device outputs are shorted to ±15 V, and the power supplies are at low and provide low-impedance
paths to ground (see Figure 15).
Figure 15. Power-Supply Protection to Meet Power-Off Fault Conditions of TIA/EIA-232-F
(1) See Figure 10 to select the correct values for the loading capacitors (C1, C2, and C3), which are required to meet the
RS-232 maximum slew-rate requirement of 30 V/μs. The value of the loading capacitors required depends on the line
length and desired slew rate, but typically is 330 pF.
Figure 16. Typical Connection
12