MAX3226EAAE+T Maxim Integrated, MAX3226EAAE+T Datasheet - Page 9

• Manufacturer Part Number: MAX3226EAAE+T
• Description: RS-232 Interface IC
• Manufacturer: Maxim Integrated
• Series: MAX3224E, MAX3225E, MAX3226E, MAX3227E, MAX3244E, MAX3245Er

Specifications of MAX3226EAAE+T

• Data Rate: 250 Kbps
• Operating Supply Voltage: 3 V to 5.5 V
• Supply Current: 1 mA
• Operating Temperature Range: 0 C to + 70 C
• Function: Transceiver
• Number Of Drivers: 1
• Number Of I/os: 4
• Number Of Receivers: 1
• Propagation Delay Time Ns: 0.15 us
• Shutdown: Yes

Figure 3. AutoShutdown Trip Levels
Figure 4. AutoShutdown with Initial Turn-On to Wake Up a
RECEIVER
VOLTAGE
OUTPUT
INVALID
a)
b)
INPUT
MANAGEMENT
(V)
(V)
Mouse or Another System
POWER-
+2.7V
+0.3V
V
V
-0.3V
-2.7V
UNIT
CC
V+
CC
V-
0
0
0
AutoShutdown, TRANSMITTERS DISABLED,
TRANSMITTERS ENABLED, INVALID HIGH
TRANSMITTERS ENABLED, INVALID HIGH
_______________________________________________________________________________________
1μA SUPPLY CURRENT, INVALID LOW
MASTER SHDN LINE
t
INVL
RS-232 Transceivers in UCSP and WLP
INDETERMINATE
INDETERMINATE
±15kV ESD-Protected +2.5V to +5.5V
FORCEOFF
MAX3230E/AE
MAX3231E/AE
0.1μF
FORCEON
t
1MΩ
INVH
INVALID
REGION
t
WU
which is then discharged into the test device through a
1.5kΩ resistor.
The IEC 1000-4-2 standard covers ESD testing and per-
formance of finished equipment. It does not specifically
refer to ICs. The MAX3230E/AE and MAX3231E/AE aid
in designing equipment that meets Level 4 (the highest
level) 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 a higher peak
current in IEC 1000-4-2, because series resistance is
lower in the IEC 1000-4-2 model. Hence, the ESD with-
stands voltage measured to IEC 1000-4-2 and is gener-
ally lower than that measured using the Human Body
Model. Figure 6a shows the IEC 1000-4-2 model, and
Figure 6b shows the current waveform for the ±8kV IEC
1000-4-2 Level 4 ESD Contact Discharge test.
The Air-Gap test involves approaching the device with a
charged probe. The Contact Discharge method connects
the probe to the device before the probe is energized.
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 manufactur-
ing. Of course, 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.
The capacitor type used for C1–C4 is not critical for
proper operation; either polarized or nonpolarized
capacitors can be used. However, ceramic chip capaci-
tors with an X7R or X5R dielectric work best. The charge
pump requires 0.1µF capacitors for 3.3V operation. For
other supply voltages, see Table 3 for required capaci-
tor values. Do not use values smaller than those listed in
Table 3. Increasing the capacitor values (e.g., by a fac-
tor of 2) reduces ripple on the transmitter outputs and
slightly reduces power consumption. C2, C3, and C4
can be increased without changing the vaue of C1.
Caution: Do not increase C1 without also increasing
the values of C2, C3, and C4 to maintain the proper
ratios (C1 to the other capacitors).
When using the minimum required capacitor values,
make sure the capacitor value does not degrade exces-
sively with temperature. If in doubt, use capacitors with
Applications Information
Capacitor Selection
Machine Model
IEC 1000-4-2
9