E
Copyright 1995 by Dallas Semiconductor Corporation.
All Rights Reserved. For important information regarding
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DS1228
+5V Powered Dual RS-232
Transmitter/Receiver
DS1228
021792 1/1
FEATURES
Operates from a single 5V power supply
Two drivers and two receivers
Meets all EIA RS-232-C specifications
On-board voltage doubler
On-board voltage inverter
+ 30V input levels
+ 9V output levels with + 5V supply
Low-power CMOS
Pin-compatible with the MAX 232
Optional 16-pin SOIC surface mount package
PIN ASSIGNMENT
16Pin DIP (300 MIL)
16Pin SOIC (300 MIL)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
C1+
V+
C1-
C2+
C2-
V-
T2OUT
R2IN
VCC
GND
T1OUT
R1IN
R1OUT
T1IN
T2IN
R2OUT
VCC
GND
T1OUT
R1IN
R1OUT
T1IN
T2IN
R2OUT
C1+
V+
C1-
C2+
C2-
V-
T2OUT
R2IN
PIN DESCRIPTION
C1+, C1
Capacitor 1 Connections
C2+, C2
Capacitor 2 Connections
V+, V-
+ 10 Volts
T1IN, T2IN
Transmitter In
T1OUT, T2OUT
Transmitter Out
R1IN, R2IN
Receiver In
R1OUT, R2OUT
Receiver Out
V
CC
+5 Volts
GND
Ground
DESCRIPTION
The DS1228 is a dual RS-232-C Receiver/Transmitter
that meets all EIA specifications while operating from a
single, +5 volt supply. The DS1228 has two internal
charge pumps. One of the charge pumps is used to gen-
erate +10 volts. The other is used to generate -10 volts.
The DS1228 also contains four level translators. Two of
the level translators are RS-232 transmitters which con-
vert TTL/CMOS inputs into +9V RS-232 outputs. The
other two level translators are capable of operating with
up to +30V inputs. The DS1228 is suitable for all RS-232
communications and is particularly valuable where
higher voltage power supplies for RS-232 drivers are
not available. The power supply section of the DS1228
supplies +10 volts from the V
CC
input.
See the DS1229 data sheet for electrical specifications
and operation.
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