Datasheet

High Data Rates
The MAX3222/MAX3232/MAX3241 maintain the RS-232
±5.0V minimum transmitter output voltage even at high
data rates. Figure 5 shows a transmitter loopback test
circuit. Figure 6 shows a loopback test result at 120kbps,
and Figure 7 shows the same test at 235kbps. For Figure
6, all transmitters were driven simultaneously at 120kbps
into RS-232 loads in parallel with 1000pF. For Figure 7, a
single transmitter was driven at 235kbps, and all transmit-
ters were loaded with an RS-232 receiver in parallel with
1000pF.
The MAX3237 maintains the RS-232 ±5.0V minimum
transmitter output voltage at data rates up to 1Mbps.
Figure 8 shows a loopback test result at 1Mbps with
MBAUD = V
CC
. For Figure 8, all transmitters were loaded
with an RS-232 receiver in parallel with 250pF.
Figure 5. Loopback Test Circuit
Figure 6. MAX3241 Loopback Test Result at 120kbps
Figure 7. MAX3241 Loopback Test Result at 235kbps
Figure 8. MAX3237 Loopback Test Result at 1000kbps
(MBAUD = V
CC
)
MAX3222
MAX3232
MAX3237
MAX3241
5kΩ
R_ IN
R_ OUT
EN
*
C2-
C2+
C1-
C1+
V-
V+
V
CC
C4
C3
C1
C2
0.1µF
V
CC
SHDN*
T_ OUT
T_ IN
GND
V
CC
0V
1000pF
* MAX3222/MAX3241 ONLY
T1IN
R1OUT
V
CC
= 3.3V
T1OUT
5V/div
5V/div
5V/div
5
µs/div
T1IN
R1OUT
V
CC
= 3.3V
T1OUT
5V/div
5V/div
2
µs/div
5V/div
T_IN
T_OUT = R_IN
5k
Ω + 250pF
R_OUT
150pF
V
CC
= 3.3V
200ns/div
+5V
0V
+5V
0V
-5V
+5V
0V
MAX3222/MAX3232/
MAX3237/MAX3241
3.0V to 5.5V, Low-Power, Up to 1Mbps,
True RS-232 Transceivers
www.maximintegrated.com
Maxim Integrated │ 11