Exar Corporation 48720 Kato Road, Fremont CA, 94538 • 510-668-7017 • www.exar.com

SP385E_100_030811

9

Figure 3. Charge Pump — Phase 2

+

+

+

+

–

–

–

–

-10V

–5V

–5V

+5V

+

+

+

+

–

–

–

–

Figure 2. Charge Pump — Phase 1

Figure 4. Charge Pump — Phase 3

–5V

–5V

+5V

+

+

+

+

–

–

–

–

Figure 5. Charge Pump — Phase 4

+

+

+

+

–

–

–

–

+10V

Shutdown (ON/OFF)

The

SP385E has a shut-down/standby mode

to conserve power in battery-powered systems.

To activate the shutdown mode, which stops

the operation of the charge pump, a logic "0" is

applied to the appropriate control line. The shut-

down mode is controlled on the

SP385E by a

logic "0" on the ON/OFF control line (pin 18 for

the SOIC and pin 20 for the SSOP packages);

this puts the transmitter outputs in a tri-state

mode.