Data Sheet

ADPL42010A

analog.com

Rev. 0

18 of 28

Figure 28. Transient Response at 1.2VOUT with 10µF COUT and

50mΩ RESR

Figure 29. Transient Response at 1.2VOUT with 100µF COUT

and 10mΩ RESR

Figure 30. Effect of ESR on Transient Response of the Regulator

Tantalum and Polytantalum Capacitors

There is a variety of tantalum capacitor types available, with a wide range of ESR specifications. Older types have

ESR specifications in the hundreds of mΩ to several Ohms. Some newer types of polytantalum with multi-electrodes

have maximum ESR specifications as low as 5mΩ. In general the lower the ESR specification, the larger the size and

the higher the price. Polytantalum capacitors have better surge capability than older types and generally lower ESR.

Some types such as the Sanyo TPE and TPB series have ESR specifications in the 20mΩ to 50mΩ range, which provide

near optimum transient response.

Aluminum Electrolytic Capacitors

Aluminum electrolytic capacitors can also be used with the ADPL42010A. These capacitors can also be used in

conjunction with ceramic capacitors. These tend to be the cheapest and lowest performance type of capacitors. The

user must take care while selecting these capacitors as some types can have ESR which can easily exceed the 3Ω

maximum value.

20µs/DIV

100

90

10

0%

VOUT = 1.2V

IOUT = 500mA WITH

500mA PULSE

COUT = 10µF

RESR = 50mΩ

50µs/DIV

100

90

10

0%

VOUT = 1.2V

IOUT = 500mA WITH

500mA PULSE

COUT = 100µF

RESR = 10mΩ

VOUT = 1.2V

IOUT = 500mA WITH 500mA PULSE

COUT = 10µF CERAMIC AND A 100µF

CAPACITOR IN SERIES WITH 40mΩ

50µs/DIV

100

90

10

0%