LD49150XX08, LD49150XX10, LD49150XX12

Application hints

Doc ID 13446 Rev 3

13/22

8

Application hints

The LD49150xx is an ultra-high performance, low dropout linear regulator, designed for high

current application that requires fast transient response. The LD49150xx operates from two

input voltages, to reduce dropout voltage. The LD49150xx is designed so that a minimum of

external component are necessary.

8.1

as low as 1.4 V, allowing conversion from very low voltage supplies to achieve low output

voltage levels with very low power dissipation.

8.2

current (3 mA typ.) even at the maximum output current level (1.5 A). A bypass capacitor on

the bias pin is recommended to improve the performance of the LD49150xx during line and

noise that could be injected into the control circuitry from the bias rail. In typical applications

8.3

External capacitors

To assure regulator stability, input and output capacitors are required as shown in the 1:

Typical application circuits.

8.4

Output capacitor

The LD49150xx requires a minimum output capacitance to maintain stability. A ceramic chip

capacitor of at least 1 µF is required. However, specific capacitor selection could be needed

to ensure the transient response. A 1 µF ceramic chip capacitor satisfies most applications

but 10 µF is recommended to ensure better transient performances. In applications where

recommended to use an output capacitors of, at least, 10 µF in order to avoid over-voltage

stress on the Input/output power pins during short circuit conditions due to parasitic

inductive effect. The output capacitor must be located as close as possible to the output pin

of the LD49150xx. The ESR (equivalent series resistance) of the output capacitor must be

within the "stable" region as shown in the typical characteristics figures. Both ceramic and

tantalum capacitors are suitable.

8.5

Minimum load current

The LD49150xx does not require a minimum load to maintain output voltage regulation.