
14
LTC1545
TYPICAL APPLICATIONS
U
10
17
18
D2
D1
LTC1545
D3
R2
R1
R3
VCC
VDD
VEE
GND
D4
1,19
2,20
3
4
5
6
7
8
9
R4EN
D4ENB
15
16
24
23
22
25
26
27
28
29
30
31
32
33
34
35
36
M0
M1
M2
DCE/DTE
11
12
13
14
D5
21
R4
R5
D2
LTC1543
RXD
RXC
TXC
SCTE
TXD
CTS
DSR
DCD
DTR
RI
LL
RTS
RL
TM
M0
M1
M2
DCE/DTE
VCC
5V
NC
3
16
17
9
15
12
24
11
2
1
5
13
6
8
22
10
20
23
4
19
7
14
1544 F23
D3
R2
R1
R3
D1
C2
1
F
C1
1
F
C5
1
F
C3
1
F
C4
3.3
F
16
10
9
7
6
4
3
8
11
12
13
5
2
15 18 17 19 20 22
LTC1344A
C6
100pF
C7
100pF
C8
100pF
VCC
5V
23 24
14
1
DCE/DTE
M2
M1
M0
CHARGE
PUMP
+
28
3
1
2
4
5
6
7
8
9
10
NC
11
12
13
14
27
26
25
24
23
22
21
20
19
18
17
16
15
VEE
M0
M1
M2
21
LATCH
C12
1
F
C13
1
F
C11
1
F
C10
1
F
C9
1
F
RXD A (104)
RXD B
RXC A (115)
RXC B
SCTE A (113)
SCTE B
TXD A (103)
TXD B
TXC A (114)
TXC B
SGND (102)
SHIELD (101)
DB-25 FEMALE
CONNECTOR
CTS A (106)
CTS B
DSR A (107)
DSR B
RTS A (105)
RTS B
DCD A (109)
DCD B
DTR A (108)
DTR B
18
*
*OPTIONAL
21
25
LL (141)
RL (140)
TM (142)
RI (125)
Figure 23. Controller-Selectable DCE Port with DB-25 Connector