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 VCC by

a 1kΩ pull-down resistor, and V- is internally connected to

ground by a 1kΩ pull up resistor.

RS-232 Drivers

With VCC = 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 VCC, 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 VCC 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

VCC

T_

R_

C1+

C1-

C2+

C2-

VCC

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+

VCC

R_

T_

C1+

C1-

C2+

C2-

VCC

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

*