MAX3160E MAXIM [Maxim Integrated Products], MAX3160E Datasheet - Page 17

• Manufacturer Part Number: MAX3160E
• Description: +5kV ESD-Protected, +3.0V to +5.5V, 10nA, RS-232/RS-485/RS-422 Multiprotocol Transceivers
• Manufacturer: MAXIM [Maxim Integrated Products]

Figure 12. RS-232 Transmitter Outputs when Exiting Shutdown
The Machine Model for ESD testing uses a 200pF stor-
age capacitor and zero-discharge resistance. It mimics
the stress caused by handling during manufacturing and
assembly. Of course, all pins (not just RS-485 inputs)
require this protection during manufacturing. Therefore,
the Machine Model is less relevant to the I/O ports than
are the Human Body Model and IEC 1000-4-2.
The capacitor type used for C1–C4 is not critical for
proper operation; polarized or nonpolarized capacitors
can be used. Ceramic chip capacitors with an X7R
dielectric provide the best combination of performance,
cost, and size. The charge pump requires 0.1µF
capacitors for 3.3V operation. For other supply volt-
ages, see
not use values smaller than those listed in
Increasing the capacitor values reduces ripple on the
transmitter outputs and slightly reduces power con-
sumption. C2, C3, and C4 can be changed without
changing C1’s value. However, do not increase C1
without also increasing the values of C2, C3, C4,
and C
other capacitors.
When using the minimum required capacitor values,
make sure the capacitance value does not degrade
excessively with temperature or voltage. This is typical
of Y5V and Z5U dielectric ceramic capacitors. If in
doubt, use capacitors with a larger nominal value. The
capacitor’s equivalent series resistance (ESR), which
RS-232/RS-485/RS-422 Multiprotocol Transceivers
BYPASS
Table 13
±15kV ESD-Protected, +3.0V to +5.5V, 10nA,
Applications Information
to maintain the proper ratios to the
______________________________________________________________________________________
for required capacitor values. Do
40µs/div
Capacitor Selection
Machine Model
SHDN
5V/div
T1OUT
2V/div
GND
T2OUT
2V/div
Table
13.
usually rises at low temperatures, influences the
amount of ripple on V+ and V-.
In applications that are sensitive to power-supply noise,
decouple V
value as reservoir capacitors C2, C3, and C4. Connect
the bypass capacitor as close to the IC as possible.
Figure 13a. Human Body ESD Test Model
Figure 13b. Human Body Model Current Waveform
AMPERES
VOLTAGE
SOURCE
HIGH-
DC
I
P
36.8%
100%
90%
10%
CHARGE-CURRENT
0
LIMIT RESISTOR
CC
0
1MΩ
to ground with a capacitor of the same
t
R
RL
C
100pF
C s
Power-Supply Decoupling
STORAGE
CAPACITOR
CURRENT WAVEFORM
TIME
1.5kΩ
RESISTANCE
DISCHARGE
R
D
t
DL
I r
PEAK-TO-PEAK RINGING
(NOT DRAWN TO SCALE)
DEVICE
UNDER
TEST
17