PRODUCT DATASHEET
AAT3221/2
PowerLinearTM
150mA NanoPower™ LDO Linear Regulator
Functional Block Diagram
IN
OUT
Over-Current
Protection
Over-Temperature
Protection
EN
VREF
GND
regulator is especially well suited for circuit applications
that are sensitive to load circuit power consumption and
extended battery life.
Functional Description
The AAT3221 and AAT3222 are intended for LDO regula-
tor applications where output current load requirements
range from no load to 150mA. The advanced circuit
design of the AAT3221/2 has been optimized for very low
quiescent or ground current consumption, making it
ideal for use in power management systems for small
battery-operated devices. The typical quiescent current
level is just 1.1μA. AAT3221/2 devices also contain an
enable circuit which has been provided to shut down the
LDO regulator for additional power conservation in por-
table products. In the shutdown state, the LDO draws
less than 1μA from input supply.
The LDO regulator output has been specifically optimized
to function with low-cost, low-ESR ceramic capacitors.
However, the design will allow for operation with a wide
range of capacitor types.
The AAT3221/2 has complete short-circuit and thermal
protection. The integral combination of these two inter-
nal protection circuits gives the AAT3221/2 a compre-
hensive safety system to guard against extreme adverse
operating conditions. Device power dissipation is limited
to the package type and thermal dissipation properties.
Refer to the Thermal Considerations section of this docu-
ment for details on device operation at maximum output
load levels.
The LDO also demonstrates excellent power supply rip-
ple rejection (PSRR) and load and line transient response
characteristics. The AAT3221/2 high performance LDO
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3221.2007.11.1.12
ANALOGICTECH [ ADVANCED ANALOGIC TECHNOLOGIES ]
