STC3232E Datasheet, PDF (6/7 Pages) List of Unclassifed Manufacturers – High ESD-Protected, Low Power, 3.3V to 5.5V, True RS-232 Transceivers

STC International Limited
http://www.mcu-memory.com
Applications Information
Capacitor Selection
The capacitor type used for C1–C4 is not critical for proper operation; polarized or non-polarized capacitors can be used.
The charge pump requires 0.1µF capacitors for 3.3V operation. 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. When using the minimum required capacitor values, make sure the capacitor value does
not degrade excessively with temperature. If in doubt, use capacitors with a larger nominal value. The capacitor’s
equivalent series resistance (ESR), which usually rises at low temperatures, influences the amount of ripple on V+ and
V- output voltages.
Power-Supply Decoupling
n most circumstances, a 0.1µF VCC bypass capacitor is adequate. In applications sensitive to power-supply noise, use a
capacitor of the same value as charge pump capacitor C1. Connect bypass capacitors as close to the IC as possible.
Operation Down to 2.7V
Transmitter outputs meet EIA/TIA-562 levels of ±3.7V with supply voltages as low as 2.7V.
Interconnection with 3V and 5V Logic
The STC3232E can directly interface with various 3V and 5V logic families, including ACT and HCT CMOS.
Pin Configurations and Typical Operating Circuits
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STC3232E Datasheet Rev.0.1, Dec.2005
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