MP6401 – 300mA LDO LINEAR REGULATOR WITH INTEGRATED RESET IC

MP6401 Rev. 1.0

www.MonolithicPower.com

13

9/7/2012

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APPLICATION INFORMATION

Adjustable Regulator Output

The OUT voltage of MP6401 has two modes

available (fixed and adjustable output voltage).

When ADJ pin is connected to GND, the regulator

works in fixed voltage mode. The regulator output

voltage will equal to preset voltage (1.8V, 2.5V or

impedance between ADJ and ground should

always be less than 50kΩ. Generally, ADJ is

connected directly to ground.

When the ADJ pin is connected to the tap of an

external resistor divider, the regulator works in

adjustable voltage mode as shown in Fig 3. The

output voltage is selected by resistor divider, thus

12

OUT

2

RR

V

1.229

R

+

=×

recommended as a good tradeoff among stability,

be not greater than 100kΩ.

Power Dissipation

The power dissipation for any package depends

on the thermal resistance of the case and circuit

board, the temperature difference between the

junction and ambient air, and the rate of airflow.

The power dissipation across the device can be

represented by the equation:

The

allowable

power

dissipation

can

be

calculated using the following equation:

between

the

junction

and

the

ambient

the junction to the ambient environment.

Connecting the GND pin of MP6401 to ground

using a large pad or ground plane helps to

channel heat away.

Output Capacitor Selection

The MP6401 is designed specifically to work with

very low ESR ceramic output capacitor 3.3uF

(min). For performance consideration, a large

ceramic capacitor such as 10uF is better. X7R or

X5R capacitor dielectric is recommended.

OUT Voltage Transient Immunity

The MP6401 can be immune to OUT pin short

negative transient. Typically, the immune duration

is 60us with 10mV overdriving. A shorter negative