Datasheet

Figure 8. Loopback Test Circuit
Figure 9. Loopback Test Result at 120kbps Figure 10. Loopback Test Result at 235kbps
Table 3. Required Capacitor Values
Table 4. Logic Family Compatibility with
Various Supply Voltages
V
CC
(V)
C1
(μF)
C2, C3, C4
(μF)
3.0 to 3.6 0.1 0.1
4.5 to 5.5 0.047 0.33
3.0 to 5.5 0.1 0.47
SYSTEM
POWER-
SUPPLY
VOLTAGE
(V)
V
CC
SUPPLY
VOLTAGE
(V)
COMPATIBILITY
3.3 3.3
Compatible with all CMOS
families.
5 5
Compatible with all TTL and
CMOS-logic families.
5 3.3
Compatible with ACT and
HCT CMOS, and with TTL.
Incompatible with AC, HC,
or CD4000 CMOS.
MAX3221
MAX3223
MAX3243
5kΩ
R_ IN
R_ OUT
EN (MAX3221/3)
C2-
C2+
C1-
C1+
V-
V+
V
CC
C4
C3
C1
C2
0.1µF
V
CC
FORCEOFF
T_ OUT
T_ IN
GND
V
CC
0V
1000pF
T1IN
R1OUT
V
CC
= +3.3V, 120kbps
C1–C4 = 0.1µF
T1OUT
5V/div
5V/div
5V/div
5µs/div
T1IN
R1OUT
V
CC
= +3.3V, 235kbps
C1–C4 = 0.1µF
T1OUT
5V/div
5V/div
2µs/div
5V/div
MAX3221/MAX3223/
MAX3243
+3V to +5.5V RS-232
Transceivers with AutoShutdown
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