MP20051 – LOW NOISE HIGH PSRR 1A LINEAR REGULATOR
MP20051 Rev.1.2 www.MonolithicPower.com 10
3/17/2017 MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
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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.
