MP20051 – LOW NOISE HIGH PSRR 1A LINEAR REGULATOR

MP20051 Rev.1.11

www.MonolithicPower.com

9

12/26/2013

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OPERATION

The MP20051 is a low-dropout linear regulator

that can supply up to 1A current, which makes it

suitable for very low voltage, low quiescent, low

noise, and high PSRR applications such as

wireless LAN transceivers, notebook computers,

smartphones, and other low-power electronics.

The MP20051 uses an internal PMOS as the

pass

element

and

includes

both

thermal

shutdown and an internal current-limiting circuit.

Dropout Voltage

Dropout voltage is the minimum input to output

differential voltage required for the regulator to

maintain an output voltage within 100mV of its

nominal value. Because the PMOS pass element

behaves as a low-value resistor, the dropout

voltage of MP20051 is only 140mV.

Shutdown

The MP20051 can be switched ON or OFF by a

logic input at the EN pin: Logic high turns the

regulator on and logic low turns it off. Tie the EN

pin to VIN if the application does not require the

shutdown feature. Do not float the EN pin.

Current Limit

The MP20051 includes a current limit structure

that monitors and controls the PMOS gate

voltage to limit the guaranteed maximum output

current to 1.6A.

Thermal Protection

Thermal protection turns off the PMOS when the

junction temperature exceeds 150°C, allowing

the IC to cool. When the IC’s junction

temperature drops by 20°C, the PMOS will turn

on again. Thermal protection limits total power

dissipation

in

the

MP20051.

For

reliable

operation, limit the junction temperature to a

maximum of 125°C.

Load-Transient Considerations

The output response of the load-transient

consists of a transient response and DC shift—

the

MP20051’s

excellent

load

regulation

effectively limits the DC shift. The output voltage

transient depends on the output capacitor’s value

and ESR. Increasing the capacitance and

decreasing the ESR will improve the transient

response.