DTR-6.5
IC BLOCK DIAGRAMS AND DESCRIPTIONS
uPD4721GS (RS-232C Driver/ Receiver)
1
2
3
4
5
6
7
8
9
10
5.5k ohm
5.5k ohm
300 ohm
300 ohm
V
DD
C
1
V
CC
C
1
C
S
C
S
D
IN1
D
IN2
R
OUT1
R
OUT2
C
4
GND
C
4
V
SS
STBY
V
CHA
D
OUT1
D
OUT2
R
IN1
R
IN2
20
19
18
17
16
15
14
13
12
11
Block diagram
Truth table
STBY
L
H
H
D
IN
X
L
H
D
OUT
Z
H
L
Standby mode (DC/DC converter is stopped)
Space level output
Mark level output
Remarks
Driver
Receiver
STBY
L
H
H
R
IN
X
L
H
R
OUT
H
H
L
Standby mode (DC/DC converter is stopped)
Space level input
Space level input
Remarks
3 V/5 V switching
V
CHA
L
H
Operating mode
5 V mode (double step-up)
3 V mode (3 times step-up)
