Datasheet

For the MAX3237E, all logic and RS-232 I/O pins are
characterized for protection to ±15kV per the Human
Body Model.
ESD Test Conditions
ESD performance depends on a variety of conditions.
Contact Maxim for a reliability report that documents test
setup, test methodology, and test results.
Human Body Model
Figure 4a shows the Human Body Model, and Figure
4b shows the current waveform it generates when dis-
charged into a low impedance. This model consists of a
100pF capacitor charged to the ESD voltage of interest,
which is then discharged into the test device through a
1.5kΩ resistor.
IEC 1000-4-2
The IEC 1000-4-2 standard covers ESD testing and per-
formance of finished equipment; it does not specifically
refer to integrated circuits. The MAX3222E/MAX3232E/
MAX3237E/MAX3241E/MAX3246E help you design
equipment that meets level 4 (the highest level) of IEC
1000-4-2, without the need for additional ESDprotection
components.
The major difference between tests done using the
Human Body Model and IEC 1000-4-2 is higher peak cur-
rent in IEC 1000-4-2, because series resistance is lower
in the IEC 1000-4-2 model. Hence, the ESD withstand
voltage measured to IEC 1000-4-2 is generally lower
than that measured using the Human Body Model. Figure
5a shows the IEC 1000-4-2 model, and Figure 5b shows
the current waveform for the ±8kV IEC 1000-4-2 level 4
ESD Contact Discharge test. The Air-Gap Discharge test
involves approaching the device with a charged probe.
The Contact Discharge method connects the probe to the
device before the probe is energized.
Machine Model
The Machine Model for ESD tests all pins using a 200pF
storage capacitor and zero discharge resistance. Its
objective is to emulate the stress caused by contact that
occurs with handling and assembly during manufacturing.
All pins require this protection during manufacturing, not
just RS-232 inputs and outputs. Therefore, after PC board
assembly, the Machine Model is less relevant to I/O ports.
Table 2. Required Minimum Capacitor
Values
Table 3. Logic-Family Compatibility with
Various Supply Voltages
Figure 6a. MAX3241E Transmitter Output Voltage vs. Load
Current Per Transmitter
V
CC
(V)
C1
(ΜF)
C2, C3, C4
(ΜF)
MAX3222E/MAX3232E/MAX3241E
3.0 to 3.6 0.1 0.1
4.5 to 5.5 0.047 0.33
3.0 to 5.5 0.1 0.47
MAX3237E/MAX3246E
3.0 to 3.6 0.22 0.22
3.15 to 3.6 0.1 0.1
4.5 to 5.5 0.047 0.33
3.0 to 5.5 0.22 1.0
SYSTEM
POWER-SUPPLY
VOLTAGE
(V)
V
CC
SUPPLY
VOLTAGE
(V)
COMPATIBILITY
3.3 3.3
Compatible with all
CMOS families
5 5
Compatible with
all TTL and CMOS
families
5 3.3
Compatible with ACT
and HCT CMOS,
and with AC, HC, or
CD4000 CMOS
-6
-5
-4
-3
-2
-1
0
1
2
3
4
5
6
0 1 2 3 4 5 6 7 8 9 10
MAX3222E-fig06a
LOAD CURRENT PER TRANSMITTER (mA)
TRANSMITTER OUTPUT VOLTAGE (V)
V
OUT+
V
OUT-
V
OUT+
V
OUT-
V
CC
V
CC
= 3.0V
www.maximintegrated.com
Maxim Integrated │ 12
MAX3222E/MAX3232E/
MAX3237E/MAX3241E/
MAX3246E
±15kV ESD-Protected, Down to 10nA,
3.0V to 5.5V, Up to 1Mbps,
True RS-232 Transceivers