±15kV ESD-Protected, EMC-Compliant, 230kbps
RS-232 Serial Port for Motherboards/Desktop PCs
______________________________________________________________Pin Description
PIN
1
12, 14, 17, 18, 19
16, 15, 13
10
11
2, 3, 4, 7, 9
5, 6, 8
20
NAME
V
DD
R5OUT–R1OUT
T3IN, T2IN, T1IN
V
SS
GND
R1IN–R5IN
T1OUT, T2OUT, T3OUT
V
CC
FUNCTION
Supply-Voltage Input, +10.8V to +13.2V
Receiver Outputs, swing between GND and V
CC
Transmitter Inputs
Supply-Voltage Input, -10.8V to -13.2V
Ground. Connect system to ground.
Receiver Inputs
Transmitter Outputs, swing between V
DD
and V
SS
Supply-Voltage Input, +4.5V to +5.5V
MAX3185
_______________Detailed Description
R
C
50M to 100M
CHARGE-CURRENT
LIMIT RESISTOR
HIGH-
VOLTAGE
DC
SOURCE
R
D
330Ω
DISCHARGE
RESISTANCE
DEVICE
UNDER
TEST
±15kV ESD Protection
As with all Maxim devices, ESD-protection structures
are incorporated on all pins to protect against electro-
static discharges encountered during handling and
assembly. The MAX3185 driver outputs and receiver
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 ESD of ±15kV, without damage. After an ESD
event, the MAX3185 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 Method specified in
IEC1000-4-2 (formerly IEC801-2)
Cs
150pF
STORAGE
CAPACITOR
Figure 1a. IEC1000-4-2 ESD Test Model
I
100%
90%
I
PEAK
ESD Test Conditions
ESD performance depends on a number of conditions.
Contact Maxim for a reliability report that documents
test setup, methodology, and results.
10%
t
r
= 0.7ns to 1ns
30ns
60ns
t
Figure 1b. IEC1000-4-2 ESD-Generator Current Waveform
_______________________________________________________________________________________
5
MAXIM [ MAXIM INTEGRATED PRODUCTS ]
