CAT660

12

Doc. No. 5000, Rev. U

+

C2

2

3

4

8

5

CAT660

"1"

+

C1

+

CAT660

"N"

2

3

4

8

5

C1

+VIN

ROUT(Of "N" CAT660’s)=

ROUT (Of the CAT660)

N (Number of devices)

PARALLEL OPERATION

Paralleling CAT660 devices will lower output resistance. As shown in figure 12, 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.

The output impedance of the combined CAT660's is:

Figure 12: Paralleling Devices Reduce Output Resistance

CASCADE OPERATION FOR HIGHER NEGATIVE VOLTAGES

The CAT660 can be cascaded as shown in figure 11 to generate more negative voltage levels. The output resistance

is approximately the sum of the individual CAT660 output resistance.

Figure 11: Cascading to Increase Output Voltage

+

C2

2

3

4

8

5

CAT660

"1"

+

C1

+

CAT660

"N"

2

3

4

8

5

C1

+VIN

+

C2

VOUT = -NVIN