MAX232ECSLASHD datasheet(10/26 Pages) AD

10 / 26 page

When in low-power shutdown mode, the MAX205E/

MAX206E/MAX211E/MAX213E/MAX241E driver outputs

are turned off and draw only leakage currents—even if

they are back-driven with voltages between 0V and12V.

Below -0.5V in shutdown, the transmitter output is diode-

clamped to ground with a 1kΩ series impedance.

RS-232 Receivers

The receivers convert the RS-232 signals to CMOS-logic

output levels. The guaranteed 0.8V and 2.4V receiver

input thresholds are significantly tighter than the ±3V

thresholds required by the EIA/TIA-232E specification.

This allows the receiver inputs to respond to TTL/CMOS-

logic levels, as well as RS-232 levels.

The guaranteed 0.8V input low threshold ensures that

receivers shorted to ground have a logic 1 output. The

5kΩ input resistance to ground ensures that a receiver

with its input left open will also have a logic 1 output.

Receiver inputs have approximately 0.5V hysteresis. This

provides clean output transitions, even with slow rise/fall-

time signals with moderate amounts of noise and ringing.

In shutdown, the MAX213E’s R4 and R5 receivers have

no hysteresis.

Shutdown and Enable Control

(MAX205E/MAX206E/MAX211E/

MAX213E/MAX241E)

In shutdown mode, the charge pumps are turned off, V+

is pulled down to VCC, V- is pulled to ground, and the

transmitter outputs are disabled. This reduces supply

current typically to 1μA (15μA for the MAX213E). The

time required to exit shutdown is under 1ms, as shown

in Figure 5.

Receivers

All MAX213E receivers, except R4 and R5, are put into a

high-impedance state in shutdown mode (see Tables 1a

and 1b). The MAX213E’s R4 and R5 receivers still func-

tion in shutdown mode. These two awake-in-shutdown

receivers can monitor external activity while maintaining

minimal power consumption.

The enable control is used to put the receiver outputs

into a high-impedance state, to allow wire-OR connection

of two EIA/TIA-232E ports (or ports of different types) at

the UART. It has no effect on the RS-232 drivers or the

charge pumps.

Note: The enable control pin is active low for the

MAX211E/MAX241E (EN), but is active high for the

MAX213E (EN). The shutdown control pin is active

Figure 4. Charge-Pump Diagram

www.analog.com

Analog Devices │ 10

MAX202E–MAX213E,

MAX232E/MAX241E

±15kV ESD-Protected,

5V RS-232 Transceivers

C1-

IL-

RL-

V+

V -

fCLK

IL+

RL+

C1+

GND

VCC

C2-

C2+

PART

fCLK

(kHz)

MAX202E

MAX211E/213E

MAX232E

MAX203E

230

MAX205E–208E

200

140

MAX241E

230

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