Datasheet

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APPLICATION INFORMATION
Capacitor Selection
ESD Protection
MAX202
5-V DUAL RS-232 LINE DRIVER/RECEIVER
WITH ± 15-kV ESD PROTECTION
SLLS576E JULY 2003 REVISED APRIL 2007
Figure 4. Typical Operating Circuit and Capacitor Values
The capacitor type used for C1–C4 is not critical for proper operation. The MAX202 requires 0.1- µ F capacitors,
although capacitors up to 10 µ F can be used without harm. Ceramic dielectrics are suggested for the 0.1- µ F
capacitors. When using the minimum recommended capacitor values, make sure the capacitance value does
not degrade excessively as the operating temperature varies. If in doubt, use capacitors with a larger (e.g., 2 × )
nominal value. The capacitors' effective series resistance (ESR), which usually rises at low temperatures,
influences the amount of ripple on V+ and V–.
Use larger capacitors (up to 10 µ F) to reduce the output impedance at V+ and V–.
Bypass V
CC
to ground with at least 0.1 µ F. In applications sensitive to power-supply noise generated by the
charge pumps, decouple V
CC
to ground with a capacitor the same size as (or larger than) the charge-pump
capacitors (C1–C4).
TI MAX202 devices have standard ESD protection structures incorporated on the pins to protect against
electrostatic discharges encountered during assembly and handling. In addition, the RS232 bus pins (driver
outputs and receiver inputs) of these devices have an extra level of ESD protection. Advanced ESD structures
were designed to successfully protect these bus pins against ESD discharge of ± 15-kV when powered down.
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