MAX3241E MAXIM [Maxim Integrated Products], MAX3241E Datasheet - Page 9

• Manufacturer Part Number: MAX3241E
• Manufacturer: MAXIM [Maxim Integrated Products]

±15kV ESD-Protected, Down to 10nA, 3.0V to 5.5V,
MAX3222E/MAX3232E/MAX3237E/MAX3241E have
extra protection against static electricity. Maxim’s engi-
neers have developed state-of-the-art structures to pro-
tect these pins against ESD of ±15kV without damage.
The ESD structures withstand high ESD in all states:
normal operation, shutdown, and powered down. After
an ESD event, Maxim’s E versions keep working without
Figure 2. Detection of RS-232 Activity when the UART and
Interface are Shut Down; Comparison of MAX3237E/
MAX3241E (b) with Previous Transceivers (a)
b) NEW MAX3237E/MAX3241E: EN SHUTS DOWN RECEIVER OUTPUTS
a) OLDER RS-232: POWERED-DOWN UART DRAWS CURRENT FROM
(EXCEPT FOR B OUTPUTS), SO NO CURRENT FLOWS TO UART IN SHUTDOWN.
B OUTPUTS INDICATE RECEIVER ACTIVITY DURING SHUTDOWN WITH EN HIGH.
ACTIVE RECEIVER OUTPUT IN SHUTDOWN.
V
V
CC
CC
UART
UART
GND
GND
PROTECTION
PROTECTION
µP
TO
DIODE
DIODE
TRANSITION
DETECTOR
LOGIC
Rx
Tx
Rx
Tx
_______________________________________________________________________________________
SHDN = GND
THREE-STATED
V
SHDN = GND
CC
V
EN = V
R1OUTB
CC
R1OUT
Up to 1Mbps, True RS-232 Transceivers
T1IN
CC
MAX3237E/MAX3241E
PREVIOUS
RS-232
5k
5k
R1IN
T1OUT
latchup, whereas competing RS-232 products can
latch and must be powered down to remove latchup.
Furthermore, the MAX3237E logic I/O pins also have
±15kV ESD protection. Protecting the logic I/O pins to
±15kV makes the MAX3237E ideal for data cable appli-
cations.
ESD protection can be tested in various ways; the
transmitter outputs and receiver inputs for the
MAX3222E/MAX3232E/MAX3241E are characterized
for protection to the following limits:
• ±15kV using the Human Body Model
• ±8kV using the Contact Discharge method specified
• ±15kV using IEC 1000-4-2’s Air-Gap Discharge
For the MAX3237E, all logic and RS-232 I/O pins are
characterized for protection to ±15kV per the Human
Body Model.
ESD performance depends on a variety of conditions.
Contact Maxim for a reliability report that documents
test setup, test methodology, and test results.
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 inter-
est, which is then discharged into the test device
through a 1.5kΩ resistor.
Figure 3. Transmitter Outputs Recovering from Shutdown or
Powering Up
in IEC 1000-4-2
method
5V/div
2V/div
0
0
V
C1–C4 = 0.1µF
CC
= 3.3V
40µs/div
ESD Test Conditions
Human Body Model
T2OUT
SHDN
T1OUT
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