Quick Charging Mode

The PL0300/P has a quick charge block to get the

reference up very quickly by charging the BYP capacitor

with very high current when the chip comes out of shut

down. This quick charge block stops charging the BYP

capacitor when the reference reaches 95% of its nominal

value and then the chip switches out of quick charging

mode to normal operating mode.

Over Temperature Protection

Over temperature protection limits the total power

dissipation in the PL0300/P. When the junction

signals the shutdown logic and turns off the pass

transistor. The thermal sensor turns the pass transistor

on again after the IC’s junction temperature drops by

15

°C, resulting in a pulsed output during continuous

thermal-overload conditions.

Thermal-overload protection is designed to protect the

PL0300/P in the event of a fault condition. For continuous

operation, do not exceed the absolute maximum junction

PL0300

APPLICATION INFORMATION

Capacitor Selection And Regulator Stability

Use a 1.0

μF capacitor on the PL0300/P input and a 1.0μF

capacitor on the output. Large input capacitor values and

lower ESR provide better noise rejection and line-

transient response.

Reduce output noise and improve load-transient

response, stability and power-supply rejection by using

large output capacitors. Note that some ceramic

dielectrics exhibit large capacitance and ESR variation

with temperature. With dielectrics such as Z5U and Y5V,

it may be necessary to use a 2.2

μF or larger output

capacitor to ensure stability at temperatures below -10

°C.

With X7R or X5R dielectrics, 1

μF is sufficient at all

operating temperatures.

Use a 0.01

μF bypass capacitor at BYP (PL0300/P-BYP) for

low-output voltage noise. The leakage current going into

the BYP pin should be less than 10nA.

Noise, PSRR and Transient Response

The PL0300/P is designed to deliver ultra-low noise and

high PSRR, as well as low dropout and low quiescent

currents in battery-powered systems. The PL0300/P PSRR

is 68dB at 100Hz and 60dB at 10KHz.

When operating from sources other than batteries,

improved supply-noise rejection and transient response

can be achieved by increasing the values of the input and

output bypass capacitors and through passive filtering

techniques.

Dropout Voltage

A regulator’s minimum dropout voltage determines the

lowest usable supply voltage. In battery-powered

systems, this determines the useful end-of-life battery

voltage. Because the PL0300/P uses a P-channel MOSFET

pass transistor, its dropout voltage is a function of drain-

current.

Operating Region and Power Dissipation

The PL0300/P’s maximum power dissipation depends on

(1) the thermal resistance of the case and circuit board,

(2) the temperature difference between the die junction

and ambient and (3) the rate of airflow. The power

dissipation across the device is:

The maximum power dissipation is:

the PL0300/P die junction and the surrounding air,

the thermal resistance of the package and

thermal resistance through the PC board, copper traces

and other materials to the surrounding air.

The GND pin of the PL0300/P performs the dual function

of providing an electrical connection to ground and

channeling heat away. Connect the GND pin to ground

using a large pad or ground plane.

Noise Reduction

For the PL0300/P, an external 0.01

μF bypass capacitor

between BYP and GND with innovative noise bypass

scheme reduces the output noises dramatically, exhibiting

70

July 2007

www.picsemi.com

© 2007 Power IC. All Rights Reserved.

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