MAX220–MAX249
+5V-Powered, Multichannel RS-232
Drivers/Receivers
+5V
TOP VIEW
1μF
1μF
20
21
C1+
V
22
CC
V+
V-
1μF
23
24
C1-
+5V TO +10V VOLTAGE DOUBLER
26
C2+
C2-
1μF
1μF
43
42 41 40
6
5
4
3
2
1
44
25
+10V TO -10V VOLTAGE INVERTER
18 ENTA
ENTB 27
+
+5V
+5V
+5V
1 TA1OUT
TB1OUT 44
TB1IN 30
RA2IN
RA1IN
ENRA
7
8
9
39 RB3IN
38 RB2IN
37 RB1IN
36 ENRB
400kΩ
15 TA1IN
2 TA2OUT
16 TA2IN
3 TA3OUT
+5V
TB2OUT 43
TB2IN 29
RA1OUT 10
RA2OUT 11
RA3OUT 12
RA4OUT 13
400kΩ
35 RB1OUT
34 RB2OUT
33 RB3OUT
32 RB4OUT
MAX249
+5V
+5V
400kΩ
TB3OUT 42
14
15
RA5OUT
TA1IN
31
RB5OUT
17 TA3IN
8 RA1IN
TB3IN 28
RB1IN 37
TA2IN 16
TA3IN 17
30 TB1IN
29 TB2IN
5kΩ
5kΩ
18 19 20 21 22 23 24 25 26 27 28
10 RA1OUT
7 RA2IN
RB1OUT 35
RB2IN 38
PLCC
5kΩ
5kΩ
11 RA2OUT
6 RA3IN
RB2OUT 34
RB3IN 39
MAX249 FUNCTIONAL DESCRIPTION
10 RECEIVERS
5 A-SIDE RECEIVERS
5kΩ
5kΩ
5 B-SIDE RECEIVERS
6 TRANSMITTERS
12 RA3OUT
5 RA4IN
RB3OUT 33
RB4IN 40
3 A-SIDE TRANSMITTERS
3 B-SIDE TRANSMITTERS
4 CONTROL PINS
5kΩ
5kΩ
ENABLE RECEIVER A-SIDE (ENRA)
ENABLE RECEIVER B-SIDE (ENRB)
ENABLE RECEIVER A-SIDE (ENTA)
ENABLE RECEIVER B-SIDE (ENTB)
13 RA4OUT
4 RA5IN
RB4OUT 32
RB5IN 41
5kΩ
5kΩ
14 RA5OUT
9 ENRA
RB5OUT 31
ENRB 36
GND
19
ꢁigure 25. MAX249 Pin Configuration and Typical Operating Circuit
34
Maxim Integrated
ROCHESTER [ Rochester Electronics ]
