AAT2503
Adjustable 3-Channel Regulator
General Description
The AAT2503 is a three-channel regulator consist-
ing of a step-down converter with an input voltage
range of 2.7V to 5.5V plus two low dropout (LDO)
linear regulators.
The step-down converter optimizes power efficien-
cy throughout the load range. Pulling the MODE/
SYNC pin high enables "PWM Only" mode, main-
taining constant frequency and low output ripple
across the operating range. Alternatively, the con-
verter may be synchronized to an external clock
input to the MODE/SYNC pin. The step-down con-
verter delivers up to 800mA of output current, while
consuming 30µA of typical no load quiescent cur-
rent. The switching frequency is 2MHz, minimizing
the size of external components.
The two LDOs (LDOA/LDOB) have independent
inputs and are capable of delivering up to 150mA
each. A Power-OK (POK) function provides an
open drain output signal when LDOA is within reg-
ulation. Both LDOs feature low quiescent current
and a low dropout voltage. The output voltages for
both LDOs are adjustable to as low as 0.6V. The
linear regulators have independent Enable pins.
The AAT2503 is available in a Pb-free 3x4mm
QFN34-20 package and is rated over the -40°C to
+85°C temperature range.
Features
•
SystemPower
™
•
•
•
•
•
•
•
800mA Step-Down Converter
— V
IN
Range: 2.7V to 5.5V
— V
OUT
Range: 0.9V to V
IN
— High Efficiency
— 2MHz Switching Frequency
Two 150mA Low Dropout Regulators
— V
OUT
Range: 0.6V to V
IN
— High Output Accuracy: ±1.5%
85µA of Total I
Q
Independent Enable Pins
Integrated Power MOSFETs
Over-Temperature and Current Limit
Protection
QFN34-20 Package
-40°C to +85°C Temperature Range
Applications
•
•
•
•
•
Cellular Phones
Digital Cameras
Handheld Instruments
Microprocessor/DSP Core/IO Power
PDAs and Handheld Computers
Typical Application
L1
LX
AAT2503
V
IN
VIN
VLDOA
VLDOB
VP
MODE/SYNC
ENA
ENB
EN
V
OUT
(Buck)
FB
OUTA
R
3
100kΩ
POK
FBA
OUTB
OUTB
POK
R
1
R
4
OUTA
C2
10μF
R
5
FBB
R
8
PGND
AGND
C6
2.2μF
R
7
C5
2.2μF
R
2
2503.2007.04.1.1
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ANALOGICTECH [ ADVANCED ANALOGIC TECHNOLOGIES ]
