Datasheet

+5V-Powered, Multichannel RS-232
Drivers/Receivers
INPUT
OUTPUT
+3V
V+
0V
V-
0V
t
PLHT
t
PHLT
t
PHLR
t
PHLS
t
PLHR
t
PLHS
50%
V
CC
50%
+3V
50%
INPUT
OUTPUT
*EXCEPT FOR R2 ON THE MAX243
WHERE -3V IS USED.
0V*
50%
GND
Figure 1. Transmitter Propagation-Delay Timing
Figure 2. Receiver Propagation-Delay Timing
EN
R
X
IN
a) TEST CIRCUIT
b) ENABLE TIMING
c) DISABLE TIMING
EN INPUT
RECEIVER
OUTPUTS
R
X
OUT
R
X
1kΩ
0V
+3V
EN
EN
+0.8V
+3.5V
OUTPUT ENABLE TIME (t
ER
)
V
CC
- 2V
V
OL
+ 0.5V
V
OH
- 0.5V
OUTPUT DISABLE TIME (t
DR
)
V
CC
- 2V
+3V
0V
150pF
EN INPUT
V
OH
RECEIVER
OUTPUTS
V
OL
1 OR 0
T
X
3kΩ
50pF
-5V
+5V
OUTPUT DISABLE TIME (t
DT
)
V+
SHDN
+3V
0V
V-
0V
a) TIMING DIAGRAM
b) TEST CIRCUIT
Figure 3. Receiver-Output Enable and Disable Timing
Figure 4. Transmitter-Output Disable Timing
Test Circuits/Timing Diagrams
Maxim Integrated
11
MAX220–MAX249
MAX220–MAX249