Detailed Description
The MAX3190/MAX3190E are EIA/TIA-232 transmitters
that convert CMOS/TTL logic levels to RS-232 signals.
They operate on ±7.5V to ±12V supplies and feature
enhanced electrostatic discharge protection (see ESD
Protection). The MAX3190/MAX3190E guarantee a
460kbps data rate with worst-case loads of 3kΩ in par-
allel with 1000pF. The MAX3190/MAX3190E invert the
TOUT signal relative to TIN (standard RS-232). The
transmitter input does not have a pullup resistor and
should be connected to GND if unused.
Shutdown
The MAX3190/MAX3190E feature a shutdown input.
Drive SHDN low to reduce the supply current to 1µA
(max). Shutdown also forces TOUT into a high-imped-
ance state, allowing the signal line to be safely con-
trolled by other transmitters. Drive SHDN high for
normal operation.
ESD Protection
As with all Maxim devices, ESD protection structures are
incorporated on all pins to protect against ESD encoun-
tered during handling and assembly. The MAX3190E’s
transmitter output has extra protection against static
electricity. Maxim has developed state-of-the-art struc-
tures enabling this pin to withstand ESD up to ±15kV
without damage or latch-up. The MAX3190E’s transmit-
ter output is characterized for protection to the following
limits:
• ±15kV using the Human Body Model
• ±8kV using the Contact Discharge method specified
in IEC 1000-4-2
• ±15kV using the Air-Gap Discharge method specified
in IEC 1000-4-2
Human Body Model
Figure 2 shows the Human Body Model, and Figure 3
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,
and 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
performance of finished equipment; it does not specifi-
cally refer to ICs. The MAX3190E enables the design of
equipment that meets the highest level (Level 4) of IEC
1000-4-2 without the need for additional ESD-protection
components. The major difference between tests done
using the Human Body Model and IEC 1000-4-2 is
higher peak current in IEC 1000-4-2. Because series
resistance is lower in the IEC 1000-4-2 model, the ESD
withstand voltage measured to this standard is general-
ly lower than that measured using the Human Body.
Figure 4 shows the IEC 1000-4-2 model, and Figure 5
MAX3190/MAX3190E
±15kV ESD-Protected, 460kbps,
RS-232 Transmitters in SOT23-6
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Pin Description
