_______________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 3kΩ and
7kΩ. The MAX1406 guarantees a 230kbps data rate
with a worst-case load of 3kΩ 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
inputs to GND or V
CC
.
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
between GND and V
CC.
±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.
MAX1406
±15kV ESD-Protected, EMC-Compliant,
230kbps, 3-Tx/3-Rx RS-232 IC
_______________________________________________________________________________________ 5
______________________________________________________________Pin Description
NAME FUNCTION
1 V
DD
Supply-Voltage Input, +10.8V to +13.2V
3, 5, 7 T1OUT, T2OUT,T3OUT Transmitter Outputs, swing between V
DD
and V
SS
PIN
2, 4, 6 R1IN, R2IN, R3IN Receiver Inputs
8 V
SS
Supply-Voltage Input, -10.8V to -13.2V
16 V
CC
Supply-Voltage Input, +4.5V to +5.5V
11, 13, 15 R3OUT, R2OUT, R1OUT Receiver Outputs, swing between GND and V
CC
10, 12, 14 T3IN, T2IN, T1IN Transmitter Inputs. Tie unused inputs to GND or V
CC.
9 GND Ground. Connect to system ground.
Figure 1. Slew-Rate Test Circuit and Timing Diagram
t
F2
t
F1
t
PHL
t
PLH
t
R1
t
R2
1.5V
3.0V
0V
0V
DRIVER
INPUT
V
OUT
V
OH
V
OL
3.3V
3.0V
-3.0V
-3.3V
R
L
C
L
SIGNAL
GENERATOR
