Date: 7/19/04

SP202E Series High Performance RS232 Transceivers

© Copyright 2004 Sipex Corporation

7

Figure 6. Charge Pump Waveforms

+10V

a) C

2

+

GND

GND

b) C

2

–

–10V

Figure 7. Charge Pump — Phase 3

–5V

+5V

–5V

+

+

++

–

–

–

–

Figure 8. Charge Pump — Phase 4

+10V

+

+

++

–

–

–

–

be symmetrical. Older charge pump approaches

inherent inefficiencies in the design.

The clock rate for the charge pump typically

operates at 15kHz. The external capacitors can

be as low as 0.1

µF with a 16V breakdown

voltage rating.

Shutdown (SD) and Enable (EN) for the

SP310E and SP312E

Both the SP310E and SP312E 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 SP310E, this control line is ON/OFF (pin

18). Activating the shutdown mode also puts the