AAT2506
1MHz Step-Down Converter/LDO Regulator
General Description
The AAT2506 is a member of AnalogicTech's Total
Power Management IC™ (TPMIC™) product fam-
ily. It is a low dropout (LDO) linear regulator and a
step-down converter with an input voltage range of
2.7V to 5.5V, making it ideal for applications with
single lithium-ion/polymer batteries.
The LDO has an independent input and is capable
of delivering up to 300mA. The linear regulator has
been designed for high-speed turn-on and turn-off
performance, fast transient response, and good
power supply rejection ratio (PSRR). Other fea-
tures include low quiescent current and a low
dropout voltage.
The AAT2506 is available in either a fixed version
with internal feedback or a programmable version
with external feedback resistors. It can deliver
600mA of load current while maintaining a low
25µA no load quiescent current. The 1MHz switch-
ing frequency minimizes the size of external com-
ponents while keeping switching losses low. The
AAT2506 feedback and control delivers excellent
load regulation and transient response with a small
output inductor and capacitor.
The AAT2506 is designed to maintain high efficien-
cy throughout the operating range, which is critical
for portable applications.
The AAT2506 is available in a 12-pin TDFN33
package, and is rated over a temperature range of
-40°C to +85°C.
Features
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SystemPower
™
V
IN
Range: 2.7V to 5.5V
V
OUT
Range: 0.6V to V
IN
300mA LDO Current Output
400mV LDO Dropout Voltage at 300mA
High Output Accuracy: ±1.5%
Fast LDO Line / Load Transient Response
600mA, 97% Efficiency Step-Down Converter
Fast Turn-On Time (100µs Typical)
25µA No Load Quiescent Current for Step-
Down Converter
Shutdown Current <1µA
Low R
DS(ON)
0.4Ω Integrated Power Switches
100% Duty Cycle Low Dropout Operation
1MHz Switching Frequency
100µs Typical Soft Start
Over-Temperature Protection
Current Limit Protection
Available in TDFN33-12 Package
-40°C to +85°C Temperature Range
Applications
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Cellular Phones
Digital Cameras
Handheld Instruments
Microprocessor/DSP Core/IO Power
PDAs and Handheld Computers
Portable Media Players
Typical Application
V
IN
= 2.7V to 5.5V
AAT2506 Step-Down Converter Efficiency
(V
OUT
= 2.5V; L = 10μH)
μ
VP
VLDO
ENLDO
OUT
BYP
GND
VCC
EN
LX
FB
SGND
PGND
4
10
C3
10μF
3
5
100
L1
4.7μH
6
7
8
11
12
1
Efficiency (%)
3.3V at 300mA
9
2
90
V
IN
= 3.3V
80
C4
2.2μF
C1
22μF
C5
10nF
U1
AAT2506
70
60
0.1
L1 Sumida CDRH3D16-4R7 C1 Murata GRM219R61A475KE19
C3 Murata GRM21BR60J106KE19
1
10
100
1000
Output Current (mA)
2506.2007.05.1.4
1
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