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

MP6402 Rev.1.0

www. MonolithicPower.com

12

4/8/2011

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OPERATION

The MP6402 integrates two low-noise, low-

dropout, low-quiescent current linear regulators

with a reset circuit. It operates from a 2.5V to

5.5V input voltage. The dual-channel LDOs can

supply up to 500mA of load current. The internal

reset circuit is used to monitor the output voltage

of channel 2. The

R E S E T

becomes active (low)

when output voltage drops below its threshold.

The MP6402 uses the internal P-channel

MOSFET as the pass element and features

internal thermal shutdown and internal current

limit circuits.

Linear Regulator

The MP6402 integrates dual-channel LDOs. The

output voltages are fixed. Their values range

from 0.9V and 3.3V with ±1.5% accuracy. Each

channel of MP6402 can supply up to 500mA of

load current.

Reset Function

The reset circuit monitors the OUT2 pin voltage.

R E S E T

is a open-drain, active-low signal pin. It

should be connected to power supply through a

pull up resistor (R1 should be larger than 10kΩ).

R E S E T

becomes active (low) when output

The thermal shutdown will make the

R E S E T

active. When the activated triggering condition is

removed,

R E S E T

will become inactive after a

pre-set

delay

time.

The

delay

time

is

programmable

through

external

capacitor

between ExtCap and GND.

EN Shutdown

The MP6402 can be switched ON or OFF by a

logic input at the EN pin. A high voltage at this

pin will turn the device on. When the EN pin is

low, the regulator is off and the supply current is

reduced. If this feature is not to be used, the EN

input should be tied to IN pin to keep the

regulator on at all time. Do not float the EN pin.

Current Limit

The MP6402 includes two independent current

limit structures which monitor and control the

gate voltage of the pass element to limit the

guaranteed maximum output current to 500mA.

Output Discharge

The part involves a discharge function that

provides a 100Ω resistive discharge path for the

external output capacitor. The function will be

active when the part is disabled and it will be

done in a very limited time.

Thermal Shutdown

Thermal protection turns off the pass element

when the junction temperature exceeds +150ºC,

allowing cooling the IC. When the IC’s junction

temperature drops by 20ºC, the pass element will

be turned on again. Thermal protection limits

total power dissipation in the MP6402. For

reliable operation, junction temperature should

be limited to 125 ºC maximum.