PRODUCT DATASHEET
AAT2504178
SystemPower
TM
General Description
The AAT2504 is a three-channel regulator consisting of a
step-down converter with an input voltage range of 2.7V
to 5.5V plus two low dropout (LDO) linear regulators.
The two LDOs have an input voltage range of 1.8V to
5.5V, making them well-suited for post regulating from
the step-down converter.
The step-down converter optimizes power efficiency
throughout the load range. Pulling the MODE/SYNC pin
high enables “PWM Only” operation, maintaining con-
stant frequency and low output ripple across the operat-
ing range. Alternatively, the converter may be synchro-
nized to an external clock to the MODE/ SYNC pin. The
step-down converter delivers up to 800mA of output 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 300mA each. Ultra
low input voltage on the VLDOA and VLDOB pins (down
to 1.62V) allows for efficient post-buck regulation. A
Power-OK (POK) function provides an open drain output
signal when LDOA is within regulation. 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.
Typical no load quiescent current is a low 80μA when the
step-down converter and LDOs are enabled.
The AAT2504 is available in a Pb-free 3x4mm QFN34-20
package and is rated over the -40°C to +85°C tempera-
ture range.
Adjustable 3-Channel Regulator
Features
• 800mA Buck Converter
▪
V
IN
Range: 2.7V to 5.5V
▪
V
OUT
Range: 0.9V to V
IN
, Adjustable
▪
High Efficiency: 95%
▪
2MHz Switching Frequency
▪
Synchronizable to External Clock
▪
Internal Soft Start
• Two 300mA Linear Regulators
▪
LDO Input Voltage Range: 1.62V to 5.5V
▪
Low Dropout Voltage
▪
High Output Accuracy: ±1.5%
• Low Total Quiescent Current I
Q
(80μA)
• Independent Enable Pins
• Over-Temperature 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
L
LX
AAT2504
V
IN
VIN
VLDOA
VLDOB
VP
MODE/SYNC
ENA
ENB
EN
V
OUT
(Step-down)
FB
OUTA
100kΩ
POK
FBA
OUTB
OUTB
POK
R
1
R
1A
OUTA
C
OUT
R
1B
FBB
R
2A
2.2μF
2.2μF
R
2
R
2B
PGND
AGND
2504.2008.02.1.2
www.analogictech.com
1
ANALOGICTECH [ ADVANCED ANALOGIC TECHNOLOGIES ]
