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Exar Corporation 48720 Kato Road, Fremont CA, 94538 • 50-668-707 • www.exar.com

SP33_00_0260

to ground and transfers the generated l0V

across C

Again, simultaneously with this, the positive

side of capacitor C

the negative side is connected to ground,

and the cycle begins again.

erated from V

V+ will show a decrease in the magnitude

inefficiencies in the design.

The clock rate for the charge pump typically

operates at 5kHz. The external capaci-

tors must be 0.µF with a 6V breakdown

rating.

External Power Supplies

For applications that do not require +5V only,

external supplies can be applied at the V+

ply voltages must be no greater than ±l0V.

The current drain for the ±0V supplies is

used for RS-232. For the RS-232 driver the

current requirement will be 3.5mAper driver.

The external power supplies should provide

a power supply sequence of :+l0V, then +5V,

followed by –l0V.

–5V

–5V

+5V

+

+

+

+

–

–

–

–

–10V

+

+

+

+

–

–

–

–

–5V

+5V

–5V

+

+

+

+

–

–

–

–

+10V

+

+

+

+

–

–

–

–

Figure . Charge Pump Phase .

Figure 2. Charge Pump Phase 2.

Figure 3. Charge Pump Phase 3.

Figure 4. Charge Pump Phase 4.

+10V

GND

GND

-10V

a) C2+

b) C2-

Figure 5. Charge Pump Waveforms