Datasheet

LP2983
SNVS170C –OCTOBER 2001–REVISED APRIL 2013 www.ti.com
Typical Performance Characteristics (continued)
Unless otherwise specified: C
IN
= 1µF, C
OUT
= 2.2µF, V
IN
= V
OUT
(NOM) +1, T
A
= 25°C, ON/OFF pin is tied to V
IN
.
Load Transient Response Load Transient Response
C
OUT
= 4.7µF C
OUT
= 2.2µF
Figure 20. Figure 21.
Application Hints
EXTERNAL CAPACITORS
Like any low-dropout regulator, the LP2983 requires external capacitors for regulator stability. These capacitors
must be correctly selected for good performance.
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.
Important: 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 guaranteed 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 will be ≥ 1 µF over the entire operating
temperature range.
Output Capacitor
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
zero ohms.
The ceramic output capacitor must be connected between the V
OUT
pin (device pin 5) and the ESR pin (device
pin 4).
See Figure 22 below.
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