MP20142 –DUAL-CHANNEL, 200mA LDO WITH PROGRAMMABLE OUTPUT VOLTAGE

MP20142 Rev.0.9

www.MonolithicPower.com

11

7/12/2010

MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited.

© 2010 MPS. All Rights Reserved.

OPERATION

The MP20142 integrates two low noise, low

dropout, low quiescent current and high PSRR

linear regulators. It is intended for use in

devices that require very low voltage, low

quiescent current power such as wireless LAN,

battery-powered equipment and hand-held

equipment.

Output

voltages

are

optional

ranging from 1.2V to 3.3V, and each channel

can supply current up to 200mA. The part uses

internal P-channel MOSFETs as the pass

elements

and

features

internal

thermal

shutdown and internal current limit.

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

P-channel

MOSFETs pass element behaves as a low-

value resistor, the dropout voltage of MP20142

is very low.

Shutdown

The MP20142 has two EN pins to control each

channel respectively. And each channel 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 output is off. The EN pin should be

tied to VIN to keep the regulator output always

on if the application does not require the

shutdown feature. Do not float the EN pins.

Output Discharge

The part involves a discharge function that

provides a 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.

Current Limit

The MP20142 includes two independent current

limit structures which monitor and control each

P-channel MOSFET’s gate voltage limiting the

guaranteed maximum output current to 660mA.

Thermal Protection

Thermal protection turns off the P-channel

MOSFETs when the junction temperature

exceeds +140ºC, allowing the IC to cool. When

the IC’s junction temperature drops by 10ºC,

the P-channel MOSFETs will be turned on

again. Thermal protection limits total power

dissipation in the MP20142. For reliable

operation, the junction temperature should be

limited to 125 ºC maximum.

Internal P-Channel Pass Device

The MP20142 features dual typical 0.6Ω P-

channel MOSFET pass devices. It provides

several advantages over similar designs using

PNP pass transistors, including longer battery

life.