Page 10

January 1999 TOKO, Inc.

TK715xx

TK715xxS

CL

ESR

APPLICATION INFORMATION

INPUT-OUTPUT CAPACITORS

Linear regulators require input and output capacitors in order to maintain regulator loop stability. The output capacitor

should be selected within the Equivalent Series Resistance (ESR) range as shown in the graphs below for stable

operation. When a ceramic capacitor is connected in parallel with the output capacitor, a maximum of 1000 pF is

recommended. This is because the ceramic capacitor's electrical characteristics (capacitance and ESR) vary widely over

temperature. If a large ceramic capacitor is used, a resistor should be connected in series with it to bring it into the stable

operating area shown in the graphs below. Minimum resistance should be added to maintain load and line transient

response.

Note: It is very important to check the selected manufacturers electrical characteristics (capacitance and ESR) over

temperature.

715xxS

CL

ESR

100

10

1

0.1

0 .01

0

50

100

IOUT (mA)

STABLE

OPERATION

AREA

100

10

1

0.1

0 .01

0

50

100

IOUT (mA)

STABLE

OPERATION

AREA

100

10

1

0.1

0 .01

0

50

100

IOUT (mA)

STABLE

OPERATION

AREA

C

C

C

Note: It is not necessary to connect a ceramic capacitor

in parallel with an aluminum or tantalum output capacitor.