Is o la t e d Tra n s fo rm e r Drive r
fo r P CMCIA Ap p lic a t io n s
MAX845
ISOLATION
BARRIER
V
IN
6
1CT:1.3CT
5V
C1
0.1µF
MBR0520
V
CC
ISO 5V
1
8
5
4
8
2
D1
IN
OUT
N.C.
SD
C3
0.1µF
C2
2.2µF
C4
2.2µF
MAX883
MAX845
ON / OFF
D2
FS
SET GND SHDN
3
MBR0520
N.C.
6
4
5
GND1 GND2
2
7
5 x 3.3k
10 x PC417
6
27, 28
13, 14
*74HC04
V
GND
T1
CC
390Ω
390Ω
390Ω
390Ω
390Ω
1
2
3
4
11
T1
IN
OUT
5
4
T1
IN
74HC04
12
18
17
16
T2
T2
OUT
IN
T2
IN
74HC04
25
24
23
T3
T3
OUT
IN
T3
IN
74HC04
T4
T4
OUT
IN
T4
IN
74HC04
T5
T5
OUT
IN
T5
IN
5 x 3.3k
74HC04
MAX225
6
390Ω
390Ω
390Ω
390Ω
390Ω
5
6
10
9
1
2
R1
R1
IN
OUT
5
4
R1
OUT
74HC04
R2
R2
IN
OUT
R2
OUT
74HC04
7
8
R3
R3
IN
OUT
R3
OUT
74HC04
22
21
19
20
R4
R4
IN
OUT
R4
OUT
74HC04
R5
R5
IN
OUT
R5
OUT
SD
EN
1
2
*74HC04 OR EQUIVALENT
4N25 LOWER SPEED, LOWER COST ALTERNATE OPTOCOUPLER CONFIGURATIONS (FOR DATA RATES BELOW 9.6kbps)
V
CC
V
CC
1N5711
4N25
6
1N5711
6
4N25
3.3k
74HCO4
3.3k
390Ω
ISO
R
OUT
1
1
R
OUT
T
IN
ISO
5
5
4
T
390Ω
ISO
IN
*74HC04
2
2
ISO
4
GND
GND
Figure 10. Typical RS-232 Application Circuit
______________________________________________________________________________________ 11
MAXIM [ MAXIM INTEGRATED PRODUCTS ]
