SP3223EB datasheet(15/23 Pages) SIPEX

15 / 23 page

Date:

10/06/06

SP3223 +3.0V to +5.5V RS-232 Transceivers

6 Sipex Corporation

ripple on the transmitter outputs and may slightly

reduce power consumption. C2, C3, and C4 can

be increased without changing C1’s value

For best charge pump efficiency locate the charge

pump and bypass capacitors as close as possible

to the IC. Surface mount capacitors are best for

this purpose.

Using capacitors with lower

equivalent series resistance (ESR) and self-

inductance, along with minimizing parasitic PCB

trace inductance will optimize charge pump

operation. Designers are also advised to consider

that capacitor values may shift over time and

operating temperature.

The Sipex-patented charge pumps are designed

to operate reliably with a range of low cost

capacitors.Either polarized or non polarized

capacitors may be used. If polarized capacitors

are used they should be oriented as shown in the

Typical Operating Circuit. The V+ capacitor

may be connected to either ground or Vcc

(polarity reversed.)

The charge pump operates with 0.1

µF capacitors

for 3.3V operation. For other supply voltages,

see the table for required capacitor values. Do

not use values smaller than those listed.

Increasing the capacitor

values (e.g., by doubling in value) reduces

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SP3223EB データシート(PDF) 15 Page - Sipex Corporation