APL5158-12BC-TRL 데이터 시트보기 (PDF) - Anpec Electronics

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APL5158-12BC-TRL

150mA CMOS Low Dropout Regulator With Power OK

Anpec Electronics 

APL5158

Application Information

Capacitor Selection and Regulator

Stability

The APL5158 use at least a 1uF capacitor on the

input. This capacitor can use Aluminum, Tantalum or

Ceramic capacitors. Input capacitor with large value

and low ESR provides better PSRR and line-transient

response. The output capacitor also can use

Aluminum, Tantalum or Ceramic capacitors, and it’s

minimum values is recommended 1uF, ESR muse be

above 0.01Ω. The Curve of the region of stable COUT

ESR vs. load current in Typical Characteristics shows

the output capacitor ESR and load current range for

APL5158 stability. Large output capacitor values can

reduce noise and improve load-transient response,

stability, and PSRR. Note that some ceramic dielec-

trics exhibit large capacitance and ESR variation with

Temperature. If use this capacitor, it may be neces-

sary to use 2.2uF or more to ensure stability at tem-

perature below -10°C.

Power Ok

The power ok function monitors the output voltage

and drives high or low to indicate a fault. When a

fault condition such as overcurrent, undervoltage, ther-

mal shutdown., or dropout occurs, the power ok out-

put is pulled low. The power ok output comes back

when the output voltage has reached 90% of it’s nomi-

nal value and with a typ. 2.5ms delay time. The power

ok is an open-drain output, connect a 10kΩ resis-

tance to VOUT for typical application

Input-Output (Dropout)Voltage

The minimun input-output voltage differential (dropout)

determines the lowest usable supply voltage. The mini-

mum input voltage is 2.7V and output voltage is 1.2V,

so the dropout voltage is 1.5V.

Reverse Protection

Load-Transient Considerations

The APL5158 Load-transient response graphs in Typi-

cal Characteristics show the transient response. A

step change in the load current from 0.1mA to 150mA

at 15u second will cause less than 10mV transient

spike. Large output capacitor’s value and low ESR

can reduce transient spike.

Shutdown/Enable

The APL5158 has an active high enable function.

Force EN high (>1.6V) enables the regulator, EN low

(<0.4V) disables the regulator and enter the shut-

down mode, it also causes the output voltage to dis-

charge through a 500Ω resistance to ground. In shut-

down mode, the quiescent current can reduce below

1uA. The EN pin cannot be floating, a floating EN pin

may cause an indeterminate state on the output. If it

is no use, connect to VIN for normal operation.

The APL5158 has a internal reverse protection, it

doesn’t need a external schottky diode to connect the

regulator input and output. If the output voltage is

forced above the input voltage, the IC will be shut-

down and the reverse output current is below 4mA , it

will increase with the output voltage. The maximum

allowable output voltage is 7V (see Absolute Maxi-

mum Rantings).

Current Limit

The APL5158 has a current limit protection, which

senses the current flows the P-channel MOSFET, and

controls the output voltage. The point where limiting

occurs is IOUT=600mA and the output voltage will be

shutdown. The output can be shorted to ground for

an indefinite amount of time without damaging the

part.

Copyright  ANPEC Electronics Corp.

10

Rev. A.5 - Aug., 2004

www.anpec.com.tw

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