Date: 10/17/ 05

SP232A Series Enhanced RS232 Transceivers

© Copyright 2005 Sipex Corporation

7

Figure 6. Charge Pump Waveforms

a) C

2

+

GND

GND

b) C

2

–

Vss

Figure 7. Charge Pump — Phase 3

–5V

+5V

–5V

+

+

++

–

–

–

–

Figure 8. Charge Pump — Phase 4

inherent inefficiencies in the design.

The clock rate for the charge pump typically

operates at greater than 15kHz. The external

capacitors can be as low as 0.1

µF with a 10V

breakdown voltage rating.

Shutdown (SD) and Enable (EN) for the

SP310A and SP312A

Both the SP310A and SP312A have a shutdown/

standby mode to conserve power in battery-pow-

ered systems. To activate the shutdown mode,

which stops the operation of the charge pump, a

logic “0” is applied to the appropriate control line.

For the SP310A, this control line is ON/OFF (pin

18). Activating the shutdown mode also puts the

Vcc = +5V

+

+

++

–

–

–

–