LP2985LV

150mA LOW NOISE, LOW DROPOUT REGULATOR

WITH SHUTDOWN FOR OUTPUT VOLTAGES <2.3 V

SLVS552 − OCTOBER 2004

9

POST OFFICE BOX 655303

APPLICATION INFORMATION

capacitors

A minimum value of 1

mF (over the entire operating temperature range) is required at the input of the LP2985LV.

In addition, this input capacitor should be located within 1 cm of the input pin and connected to a clean analog

ground. There are no Equivalent Series Resistance (ESR) requirements for this capacitor and the capacitance

can be increased without limit.

As an advantage over other regulators, the LP2985LV permits the use of low ESR capacitors at the output,

including ceramic capacitors that can have an ESR as low as 5 m

Ω. Of course, tantalum and film capacitors

can also be used if size and cost are not issues. The output capacitor should also be located within 1 cm of the

output pin and be returned to a clean analog ground.

As with other PNP LDOs, stability conditions require the output capacitor to have a minimum capacitance and

an ESR that falls within a certain range.

ESR range: See Figures 1 and 2

Figure 1. 2.2-

µF Stable ESR Curves

Figure 2. 4.7-

µF Stable ESR Curves