MAX3384E Datasheet, PDF (7/11 Pages) Maxim Integrated Products – ±15kV ESD-Protected, 3.0V to 5.5V, Low-Power, up to 250kbps, True RS-232 Transceiver

±15kV ESD-Protected, 3.0V to 5.5V, Low-Power,
up to 250kbps, True RS-232 Transceiver
R_C
1M
CHARGE-CURRENT
LIMIT RESISTOR
HIGH-
VOLTAGE
DC
SOURCE
Cs
100pF
R_D
1500Ω
DISCHARGE
RESISTANCE
STORAGE
CAPACITOR
Figure 3a. Human Body ESD Test Model
DEVICE
UNDER
TEST
I_P 100%
90%
Ir
PEAK-TO-PEAK RINGING
(NOT DRAWN TO SCALE)
AMPERES
36.8%
10%
0
0 _tRL
TIME
t_DL
CURRENT WAVEFORM
Figure 3b. Human Body Model Current Waveform
R_C
50M to 100M
CHARGE-CURRENT
LIMIT RESISTOR
HIGH-
VOLTAGE
DC
SOURCE
Cs
150pF
R_D
330Ω
DISCHARGE
RESISTANCE
STORAGE
CAPACITOR
DEVICE
UNDER
TEST
I
100%
90%
10%
tr = 0.7ns to 1ns
t
30ns
60ns
Figure 4a. IEC 1000-4-2 ESD Test Model
Figure 4b. IEC 1000-4-2 ESD Generator Current Waveform
can be used. The charge pump requires 0.1µF capaci-
tors for 3.3V operation. For other supply voltages, refer
to Table 2 for required capacitor values. Do not use val-
ues smaller than those listed in Table 2. Increasing the
capacitor values (e.g., by a factor of 2) reduces ripple
on the transmitter outputs and slightly reduces power
consumption. C2, C3, and C4 can be increased without
changing C1’s value. However, do not increase C1
without also increasing the values of C2, C3, C4,
and C_BYPASS 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
excessively with temperature. If in doubt, use capaci-
tors with a larger nominal value. The capacitor’s equiva-
lent series resistance (ESR), which usually rises at low
temperatures, influences the amount of ripple on V+
and V-.
Power-Supply Decoupling
In most circumstances, a 0.1µF V_CC bypass capacitor
is adequate. In applications that are sensitive to power-
supply noise, use a capacitor of the same value as
charge-pump capacitor C1. Connect bypass capaci-
tors as close to the IC as possible.
Operation Down to 2.7V
Transmitter outputs will meet EIA/TIA-562 levels of
±3.7V with supply voltages as low as 2.7V.
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