1.425V to 3.6V Input, 1A Low-Dropout

Regulators with BIAS Input

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7

Functional Diagram

INTERNAL

SUPPLY

GENERATOR

BIAS

UVLO

IN

UVLO

CONTROL

LOGIC

P

REF

ERROR

AMPLIFIER

WITH

SOFT-START

OVERTEMPERATURE

PROTECTION

MOS DRIVER

BIAS

IN

EN

FB

SS

OUT

GND

MAX15028

ONLY

MAX15027

ONLY

REF

MAX15027

MAX15028

Detailed Description

The MAX15027/MAX15028 low-dropout linear regula-

tors operate from input voltages as low as 1.425V and

deliver up to 1A of continuous output current with a

maximum dropout voltage of only 225mV.

The MAX15028 operates with an input voltage as low

available. The power is applied at IN while the control

is provided through BIAS input. The current drawn by

BIAS is negligible when the LDO goes into shutdown.

This feature is especially useful in automotive applica-

tions where the BIAS input is derived from an always-

on LDO that expects to provide minimal power during

the key-off condition.

The pMOS output stage can be driven from input volt-

ages down to +1.425V without sacrificing stability or

transient performance. The output voltage of all the

accurate over load and line variations, from -40°C to

+125°C. Since these regulators have a pMOS output

device, supply current is not a significant function of

load or input headroom.