APL5151 데이터 시트보기 (PDF) - Anpec Electronics

부품명

상세내역

제조사

APL5151

Low IQ, Low Dropout 150mA Fixed Voltage Regulator

Anpec Electronics 

APL5151/2/3/4

Application Information

Capacitor Selection and Regulator

Stability

The APL5151/2/3/4 use at least a 1uF capacitor on

the input, and this capacitor can be Aluminum, Tanta-

lum or Ceramic capacitor. The input capacitor with

larger value and lower ESR provides better PSRR and

line-transient response. The output capacitor also can

use Aluminum, Tantalum or Ceramic capacitor, and a

minimum value of 1uF and ESR above 0.06Ω is

recommended. The curve of the stable region in typi-

cal characteristics shows the appropriate output ca-

pacitor ESR for different load current stable operation.

A larger output capacitor can reduce noise and im-

prove load-transient response, stability, and PSRR.

Note that some ceramic dielectrics exhibit large ca-

pacitance and ESR variation with temperature. When

using this capacitor, a minimum 2.2uF or more may

be required to ensure the stability at low temperature

operation. Use a bypass capacitor at BP pin for low

output nvise. Increasing the capacitance will slightly

decrease the output noise, but increase the start-up

time. (See Shutdown Exit Delay and Output Noise

vs.Bypass Capacitor graph in the typical

characteristics)

Load-Transient Considerations

The APL5151/2/3/4 load-transient response graphs in

typical characteristics show the transient response.

A step change in the load current from 1mA to 50mA

at 1us will cause a 60mV transient spike. Larger out-

put capacitor and lower ESR can reduce transient

spike.

Input-Output (Dropout)Voltage

The minimum input-output voltage difference (dropout)

determines the lowest usable supply voltage. In bat-

tery-powered systems, this will determine the useful

end-of-life battery voltage. Because the APL5151/2/

3/4 use a p-channel MOSFET pass transistor, the drop-

out voltage is a function of drain-to-source on-resis-

tance (RDS(ON)) multiplied by the load current.

Reverse Current Protection

The APL5151/2/3/4 have an internal reverse protection,

it does not need an external schottky diode to con-

nect the regulator input and output. If the output volt-

age is forced above the input voltage by more than

11mV, the IC will be shutdown and the ground pin

current is below 0.1uA.

Current Limit

The APL5151/2/3/4 have a current limit protection. The

ouptut voltage will drop close to zero volt, when load

current reaches the limit, and then the load current

will be limited at 50mA after output voltage is below 0.

7V. When the load current back to the value where

limiting started, the output voltage and current will re-

turn to normal value. When output is shorted to

ground, the APL5151/2/3/4 will keep short circuit cur-

rent at 150mA .

Copyright © ANPEC Electronics Corp.

11

Rev. B.4 - May., 2005

www.anpec.com.tw

Share Link: