MAX3316E–MAX3319E
±15kV ESD-Protected, 2.5V, 1µA, 460kbps,
RS-232 Compatible Transceivers
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By connecting FORCEON to INVALID, the MAX3318E/
MAX3319E shut down when no valid receiver level is
detected and wake up when a valid receiver level is
detected.
A system with AutoShutdown Plus may need time to
wake up. Figure 5 shows a circuit that forces the trans-
mitters on for 100ms, allowing enough time for the other
system to realize that the MAX3318E/MAX3319E is
awake. If the other system outputs valid RS-232 signal
transitions within that time, the RS-232 ports on both
systems remain enabled.
Connecting to the PC
(MAX3318E/MAX3319E)
If direct software control is desired, use INVALID to
indicate DTR or ring indicator (RI) signal. This can be
used to connect a hand-held device to a PC. One
example is using the Hot Sync™ function on a personal
digital assistant (PDA). The transmitter and receiver
signals (T_OUT and R_IN) are used for communication,
while INVALID causes a change of state on RI. The
change of state on RI will trigger an interrupt on the PC
and allow communication to begin between the device
and the PC. This eliminates the need for the PC to poll
constantly the receiver or transmitter lines to determine
if the device is connected.
±15kV ESD Protection
All the pins on the MAX3316E–MAX3319E are protect-
ed against ESDs encountered during handling and
assembly. The driver outputs and receiver inputs 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
latchup, whereas competing products can latch and
must be powered down to remove latchup.
ESD protection can be tested in various ways; the trans-
mitter outputs and receiver inputs of the product family
are characterized for protection to the following limits:
• ±15kV using the Human Body Model
• ±8kV using the IEC 1000-4-2 Contact Discharge
method
• ±15kV using IEC 1000-4-2 Air-Gap method
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 6a shows the Human Body Model, and Figure 6b
shows the current waveform it generates when dis-
charged into 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.
