Rainbow Electronics MAX15028 - Manual (Page 7)

MAX15027/MAX15028
1.425V to 3.6V Input, 1A Low-Dropout
Regulators with BIAS Input
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Functional Diagram
INTERNAL
SUPPLY
GENERATOR
BIAS
UVLO
IN
UVLO
CONTROL
LOGIC
P
REF
ERROR
AMPLIFIER
WITH
SOFT-START
OVERTEMPERATURE
PROTECTION
MOS DRIVER
WITH I LIMIT
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
as 1.425V if the bias voltage (V
BIAS
) of 3V to 5.5V is
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
regulators is adjustable from 0.5V to V
IN
and is ±2%
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.