Datasheet

±15kV ESD-Protected, 1µA, 3.0V to 5.5V, 250kbps,
RS-232 Transceivers with AutoShutdown
Pin Description
PIN
MAX3221E MAX3223E MAX3243E
TQFN-
EP
SSOP/
TSSOP
TQFN-
EP
DIP/
SSOP/
TSSOP
SO/
SSOP/
TSSOP
TQFN-
EP
NAME
FUNCTION
14 1 19 1 — 22 EN
Receiver Enable Control. Drive low for normal
operation. Drive high to force the receiver outputs
(R_OUT) into a high-impedance state.
16 2 1 2 28 28 C1+
Positive terminal of the voltage doubler Charge-Pump
Capacitor
15 3 20 3 27 27 V+ +5.5V generated by the charge pump
1 4 2 4 24 23 C1-
Negative terminal of the voltage doubler Charge-Pump
Capacitor
2 5 3 5 1 29 C2+ Positive terminal of inverting Charge-Pump Capacitor
3 6 4 6 2 30 C2- Negative terminal of inverting Charge-Pump Capacitor
4 7 5 7 3 31 V- -5.5V generated by the charge pump
5 8 7, 14 9, 16 4-8 1-5 R_IN RS-232 Receiver Inputs
6 9 8, 13 10, 15 15-19
13, 14,
15, 17,
18
R_OUT TTL/CMOS Receiver Outputs
7 10 9 11 21 — INVALID
Output of the Valid Signal Detector. INVALID is enabled
high if a valid RS-232 level is present on any receiver
input.
8 11 10, 11 12, 13
12, 13,
14
10, 11,
12
T_IN TTL/CMOS Transmitter Inputs
9 12 12 14 23 — FORCEON
Drive high to override automatic circuitry keeping
transmitters and charge pump on (FORCEOFF must be
high) (Table 1).
10 13 6, 15 8, 17
9, 10,
11
6, 7, 8 T_OUT RS-232 Transmitter Outputs
— — — — 20 19 R2OUTB
TTL/CMOS Noninverting Complementary Receiver
Output. Always active.
11 14 16 18 25 24 GND Ground
12 15 17 19 26 26 V
CC
+3.0V to +5.5V Supply Voltage
13 16 18 20 22 —
FORCEOF
F
Force-Off Input, active low. Drive low to shut down
transmitters, receivers (MAX3243E, except R2OUTB),
and on-board charge pump. This overrides all
automatic circuitry and FORCEON (Table 1).
— — — — — 21 SHDN Shutdown Control, Active Low
6
Maxim Integrated
MAX3221E/MAX3223E/MAX3243E