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LP2983

SNVS170D – OCTOBER 2001 – REVISED APRIL 2016

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8.2.2 Detailed Design Procedure

8.2.2.1 External Capacitors

Like any low-dropout regulator, the LP2983 requires external capacitors for regulator stability. These capacitors

must be correctly selected for good performance.

8.2.2.1.1

Input Capacitor

An input capacitor whose capacitance is

≥ 1 µF is required between the LP2983 input and ground (the amount of

capacitance may be increased without limit).

This capacitor must be located a distance of not more than 1 cm from the input pin and returned to a clean

analog ground. Any good-quality ceramic, tantalum, or film capacitor may be used at the input.

NOTE

Tantalum capacitors can suffer catastrophic failure due to surge current when connected

to a low-impedance source of power (like a battery or very large capacitor). If a tantalum

capacitor is used at the input, it must be ensured by the manufacturer to have a surge

current rating sufficient for the application.

There are no requirements for ESR on the input capacitor, but tolerance and temperature coefficient must be

considered when selecting the capacitor to ensure the capacitance is

≥ 1 µF over the entire operating

temperature range.

8.2.2.1.2

Output Capacitors

The LP2983 is designed specifically to work with ceramic output capacitors, utilizing circuitry which allows the

regulator to be stable across the entire range of output current with an output capacitor whose ESR is as low as

0

Ω.

The ceramic output capacitor must be connected between the OUT pin (device pin 5) and the ESR pin (device

pin 4) (see Figure 24).

The LP2983 requires a minimum of 2.2 µF on the output (output capacitor size can be increased without limit).

It is important to remember that capacitor tolerance and variation with temperature must be taken into

consideration when selecting an output capacitor so that the minimum required amount of output capacitance is

provided over the full operating temperature range. Note that ceramic capacitors can exhibit large changes in

capacitance with temperature (see Capacitor Characteristics).

The output capacitor must be located not more than 1 cm from the output pin and returned to a clean analog

ground via the ESR pin.