General Description
The AAT2505 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 cell lithium-ion / polymer batteries.
The LDO has an independent input pin and is capa-
ble of delivering up to 300mA of current. 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 features include low quiescent current, low
dropout voltage, and a Power-OK (POK) open drain
output signaling when V
OUT
is in regulation.
The 600mA step-down converter is designed to
operate with 1.4MHz of switching frequency, mini-
mizing external component size and cost while
maintaining a low 27µA no load quiescent current.
Peak current mode control with internal compen-
sation provides a stable converter with a low equiv-
alent series resistance (ESR) ceramic output
capacitor for extremely low output ripple.
For maximum battery life with high voltage outputs,
the step-down converter duty cycle increases to
100%. The output voltage is either fixed or adjustable
with an integrated P- and N-channel MOSFET power
stage and 1.4MHz switching frequency.
The AAT2505 is available in a Pb-free, 12-pin
TDFN33 package and is rated over a temperature
range of -40°C to +85°C.
Features
•V
IN
Range: 2.7V to 5.5V
• 300mA LDO
— 400mV Dropout Voltage at 300mA
— High Accuracy: ±1.5%
— Fast Line / Load Transient Response
— Power OK Output
• 600mA Step-Down Converter
— Up To 98% Efficiency
— 27µA No Load Quiescent Current
— Shutdown Current <1µA
— Low R
DS(ON)
Integrated Power Switches
— Fast Turn-On Time (150µs Typical)
— Low Dropout 100% Duty Cycle
— 1.4MHz Switching Frequency
— Internal Soft Start
• Over-Temperature and Current Limit
Protection
• TDFN33-12 Package
• -40°C to +85°C Temperature Range
Applications
• Cellular Phones
• Digital Cameras
• Handheld Instruments
• Microprocessor/DSP Core/IO Power
• PDAs and Handheld Computers
• Portable Media Players
AAT2505
Dual Channel, Step-Down
Converter/Linear Regulator
Typical Application
Efficiency
(V
OUT
= 2.5V; L = 6.8µH)
Output Current (mA)
Efficiency (%)
60
70
80
90
100
0.1 1 1 0 100 1000
V
IN
= 3.3V
6.8µH
L1
C1
4.7µF
2.2 µ F
C4
10µF
C3
R3 100k Ω
PGND
1
LX
2
VP
3
VCC
4
ENLDO
9
EN
10
FB
11
SGND
12
VLDO
5
OUT
6
GND
8
POK
7
AA T 2 505
U1
L 1 S u m i da C D R H 3D 16- 4 R 7 C 1 M u r a t a GR M 2 1 9 R 6 1A 475 KE 19
C 3 M u r a t a GR M 21B R 60J 106 KE 1 9
V IN = 2.7V to 5.5V
3.3V at 300mA
2.5V at 600mA
2505.2006.06.1.1 1
SystemPower
™