Manufacturer

Phone

Capacitor Type

Murata

(800)-831-9172

Ceramic chip capacitors

Taiyo Yuden

(800)-348-2496

Ceramic chip capacitors

Tokin

(408)-432-8020

Ceramic chip capacitors

Other Applications

Paralleling Devices

Any number of LM828s can be paralleled to reduce the out-

put resistance. Each device must have its own pumping ca-

pacitor C

shown in Figure 3. The composite output resistance is:

Cascading Devices

Cascading the LM828s is an easy way to produce a greater

negative voltage (e.g. A two-stage cascade circuit is shown

in Figure 4).

If n is the integer representing the number of devices cas-

caded, the unloaded output voltage V

tive output resistance is equal to the weighted sum of each

individual device:

R

This can be seen by first assuming that each device is 100

percent efficient. Since the output voltage is different on

each device the output current is as well. Each cascaded de-

vice sees less current at the output than the previous so the

R

the number of n is practically limited since the increasing of

n significantly reduces the efficiency, and increases the out-

put resistance and output voltage ripple.

DS100137-9

FIGURE 3. Lowering Output Resistance by Paralleling Devices

DS100137-10

FIGURE 4. Increasing Output Voltage by Cascading Devices

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