MP6402 –DUAL 500MA LDO LINEAR REGULATORS WITH INTEGRATED RESET IC

MP6402 Rev.1.0

www. MonolithicPower.com

13

4/8/2011

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APPLICATION INFORMATION

Operating Region and Power Dissipation

The maximum power dissipation of MP6402

depends on the thermal resistance of the case

and circuit board, the temperature difference

between the die junction and ambient air, and the

rate of airflow. The power dissipation across the

device is

The maximum power dissipation is:

difference between the MP6402 die junction and

resistance from the junction to the surrounding

environment. The FIN of the MP6402 performs

the dual function of providing an electrical

connection to ground and channeling heat away.

Connect the FIN to ground using a large pad or

ground plane.

Input Capacitor Selection

Using a capacitor whose value is higher than 1µF

on the MP6402 input and the amount of

capacitance can be increased without limit.

Larger values will help improve line transient

response with the drawback of increased size.

Ceramic capacitors are preferred.

Output Capacitor Selection

The MP6402 is designed specifically to work with

very low ESR ceramic output capacitor in space-

saving

and

performance

consideration.

A

ceramic capacitor in the range of 3.3µF and 10µF,

and with ESR lower than 0.5Ω is suitable for the

MP6402 application circuit. Output capacitor of

larger values will help to improve load transient

response and reduce noise with the drawback of

increased size.

Programmable Reset Delay Time

The reset delay time is determined by the value

of external capacitor (C4) connected to ExtCap

pin. Typically the reset delay time is 2.1mSec

when the external capacitor is 3300pF. For a

given delay time, the capacitor value can be

calculated using the following equation:

0.1

]

6

.

0

)

nF

(

C

[

)

ms

(

T

4

D

+

×

=

The reset delay time is determined by the charge

time of external capacitor. Stray capacitance may

cause errors of the delay time.

A ceramic

capacitor

with

low

leakage

is

strongly

recommended.