_______________Detailed Description

RS-232 Transmitters

The transmitters are inverting level translators that con-

vert CMOS-logic input levels to an EIA/TIA-232 voltage

between ±5V and ±13.2V, into a load between 3k

Ω and

7k

Ω. The MAX1406 guarantees a 230kbps data rate

with a worst-case load of 3k

Ω and 1000pF, providing

compatibility with PC-to-PC communication software.

When the power is off, the MAX1406 outputs are permit-

ted to be driven up to ±15V. The transmitter inputs do

not have internal pull-up resistors. Connect unused

RS-232 Receivers

The receiver inputs invert and convert the RS-232 sig-

nals to CMOS-logic output levels. The MAX1406 has

hysteresis of 650mV. The receiver output swings

±15kV ESD Protection

As with all Maxim devices, electrostatic discharge

(ESD) protection structures are incorporated on all pins

to protect against ESD encountered during handling

and assembly. The MAX1406 driver outputs and receiv-

er inputs have extra protection against static electricity

found in normal operation. Maxim’s engineers devel-

oped state-of-the-art structures to protect these pins

against ±15kV ESD without damage. After an ESD

event, the MAX1406 continues working without latchup.

ESD protection can be tested in several ways. The

transmitter outputs and the receiver inputs are charac-

terized for protection to the following:

1) ±15kV using the Human Body Model

2) ±8kV using the Contact-Discharge method specified

in IEC1000-4-2 (formerly IEC801-2)

3) ±15kV using the Air-Gap Discharge method speci-

fied in IEC1000-4-2 (formerly IEC801-2)

ESD Test Conditions

ESD performance depends on a number of conditions.

Contact Maxim for a reliability report that documents

test setup, methodology, and results.

±15kV ESD-Protected, EMC-Compliant,

230kbps, 3-Tx/3-Rx RS-232 IC

_______________________________________________________________________________________

5

______________________________________________________________Pin Description

NAME

FUNCTION

1

Supply-Voltage Input, +10.8V to +13.2V

3, 5, 7

T1OUT, T2OUT,T3OUT

PIN

2, 4, 6

R1IN, R2IN, R3IN

Receiver Inputs

8

Supply-Voltage Input, -10.8V to -13.2V

16

Supply-Voltage Input, +4.5V to +5.5V

11, 13, 15

R3OUT, R2OUT, R1OUT

10, 12, 14

T3IN, T2IN, T1IN

9

GND

Ground. Connect to system ground.

Figure 1. Slew-Rate Test Circuit and Timing Diagram

1.5V

3.0V

0V

0V

DRIVER

INPUT

3.3V

3.0V

-3.0V

-3.3V

SIGNAL

GENERATOR