CAT661

http://onsemi.com

13

Cascade Operation for Higher Negative Voltages

The CAT661 can be cascaded as shown in Figure 28 to generate more negative voltage levels. The output resistance is

approximately the sum of the individual CAT661 output resistance.

Figure 28. Cascading to Increase Output Voltage

+

C2

4

8

5

+

C1

+

CAT661

4

8

5

C1N

+

C2

3

2

“N”

CAT661

“1”

3

2

Parallel Operation

Paralleling CAT661 devices will lower output resistance. As shown in Figure 29, each device requires its own pump

capacitor, C2, but the output reservoir capacitor is shared with all devices. The value of C2 should be increased by a factor of

N, where N is the number of devices.

ROUT +

ROUT (of CAT661)

N (NUMBER OF DEVICES)

Figure 29. Reduce Output Resistance BY Paralleling Devices

+

C2

4

8

5

+

C1

+

4

8

5

C1N

CAT661

3

2

“N”

CAT661

“1”

3

2