Datasheet

Detailed Description
The MAX202E–MAX213E, MAX232E/MAX241E consist
of three sections: charge-pump voltage converters, driv-
ers (transmitters), and receivers. These E versions pro-
vide extra protection against ESD. They survive ±15kV
discharges to the RS-232 inputs and outputs, tested
using the Human Body Model. When tested according
to IEC1000-4-2, they survive ±8kV contact-discharges
and ±15kV air-gap discharges. The rugged E versions
are intended for use in harsh environments or applica-
tions where the RS-232 connection is frequently changed
(such as notebook computers). The standard (non-
“E”) MAX202, MAX203, MAX205–MAX208, MAX211,
MAX213, MAX232, and MAX241 are recommended for
applications where cost is critical.
+5V to ±10V Dual Charge-Pump
Voltage Converter
The +5V to ±10V conversion is performed by dual charge-
pump voltage converters (Figure 4). The first charge-
pump converter uses capacitor C1 to double the +5V into
+10V, storing the +10V on the output filter capacitor, C3.
The second uses C2 to invert the +10V into -10V, storing
the -10V on the V- output filter capacitor, C4.
In shutdown mode, V+ is internally connected to V
CC
by
a 1kΩ pull-down resistor, and V- is internally connected to
ground by a 1kΩ pull up resistor.
RS-232 Drivers
With V
CC
= 5V, the typical driver output voltage swing is
±8V when loaded with a nominal 5kΩ RS-232 receiver.
The output swing is guaranteed to meet EIA/TIA-232E
and V.28 specifications that call for ±5V minimum output
levels under worst-case conditions. These include a 3kΩ
load, minimum V
CC
, and maximum operating tempera-
ture. The open-circuit output voltage swings from (V+ -
0.6V) to V-.
Input thresholds are CMOS/TTL compatible. The unused
drivers’ inputs on the MAX205E–MAX208E, MAX211E,
MAX213E, and MAX241E can be left unconnected
because 400kΩ pull up resistors to V
CC
are included on-
chip. Since all drivers invert, the pull up resistors force the
unused drivers’ outputs low. The MAX202E, MAX203E,
and MAX232E do not have pull up resistors on the
transmitter inputs.
Figure 3. Transition Slew-Rate Circuit
www.analog.com
Analog Devices │ 9
MAX202E–MAX213E,
MAX232E/MAX241E
±15kV ESD-Protected,
5V RS-232 Transceivers
V+
MAX2_ _E
V
CC
T_
R_
C1+
C1-
C2+
C2-
V
CC
T_OUT
R_OUT
EN (EN)
SHDN (SHDN)
400kΩ 400kΩ
5kΩ
3Ωk
+5V
R_IN
T_IN
MINIMUM SLEW-RATE TEST CIRCUIT
0V (+5V)
0V (+5V)
2500pF
V-
V+
V
CC
R_
T_
C1+
C1-
C2+
C2-
V
CC
T_OUT
R_OUT
EN (EN)
SHDN (SHDN)
5kΩ
7kΩ
+5V
R_IN
T_IN
MAXIMUM SLEW-RATE TEST CIRCUIT
0V (+5V)
0V (+5V)
50pF
V-
( ) ARE FOR MAX213E
* 1µF FOR MAX232E/MAX241E
MAX2_ _E
TRANSMITTER INPUT PULL-UP RESISTORS, ENABLE, AND SHUTDOWN ARE NOT PROVIDED ON THE MAX202E, MAX203E, AND MAX232E.
ENABLE AND SHUTDOWN ARE NOT PROVIDED ON THE MAX207E AND MAX208E.
0.1µF* 0.1µF*
0.1µF*
0.1µF*
0.1µF*
0.1µF*
0.1µF* 0.1µF*
0.1µF*
0.1µF*