DATA SHEET
AAT2505
Dual Channel, Step-Down Converter/Linear Regulator
General Description
The AAT2505 is a member of Skyworks' Total Power
Management IC (TPMIC™) product family. It is a low
dropout (LDO) linear regulator and a step-down con-
verter with an input voltage range of 2.7V to 5.5V, mak-
ing it ideal for applications with single cell lithium-ion /
polymer batteries.
The LDO has an independent input pin and is capable 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 regula-
tion.
The 600mA step-down converter is designed to operate
with 1.4MHz of switching frequency, minimizing external
component size and cost while maintaining a low 27μA
no load quiescent current.
Peak current mode control with internal compensation
provides a stable converter with a low equivalent 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 inte-
grated 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
Typical Application
V
IN
= 2.7V to 5.5V
C3
10μF
(V
OUT
= 2.5V; L = 6.8µH)
3
5
Efficiency
VP
VLDO
ENLDO
OUT
POK
GND
VCC
EN
LX
FB
SGND
PGND
4
10
2.5V at 600mA
100
3.3V at 300mA
L1
2
9
6
6.8μH
11
12
1
Efficiency (%)
90
R3 100kΩ
V
IN
= 3.3V
80
7
8
C4
2.2μF
C1
4.7μF
U1
AAT2505
70
60
0.1
1
10
100
1000
L1 Sumida CDRH3D16-4R7 C1 Murata GRM219R61A475KE19
C3 Murata GRM21BR60J106KE19
Output Current (mA)
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
202018B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • March 19, 2013
1
DATA SHEET
AAT2505
Dual Channel, Step-Down Converter/Linear Regulator
Pin Descriptions
Pin #
1
2
3
4
5
6
7
8
9
10
11
Symbol
PGND
LX
VP
VCC
VLDO
OUT
POK
GND
ENLDO
EN
FB
Function
Step-down converter power ground return pin. Connect to the output and input capacitor return. See sec-
tion on PCB layout guidelines and evaluation board layout diagram.
Power switching node. Output switching node that connects to the output inductor.
Step-down converter power stage supply voltage. Must be closely decoupled to PGND.
Step-down converter bias supply. Connect to VP.
LDO input voltage; should be decoupled with 1μF or greater capacitor.
300mA LDO output pin. A 2.2μF or greater output low-ESR ceramic capacitor is required for stability.
Power-OK output for the LDO. This open drain output is low when the OUT is out of regulation. Connect a
pull-up resistor from POK to OUT or VLDO. When LDO is in shutdown (ENLDO = 0V), POK is pulled low.
LDO ground connection pin.
Enable pin for LDO. When connected low, LDO is disabled and consumes less than 1μA of current.
Step-down converter enable. When connected low, the step-down converter is disabled and consumes
less than 1μA.
Step-down converter feedback input pin. For
fi
xed output voltage versions, this pin is connected to the
converter output, forcing the converter to regulate to the specific voltage. For adjustable output versions,
an external resistive divider ties to this point and programs the output voltage to the desired value.
Step-down converter signal ground. For external feedback, return the feedback resistive divider to this
ground. For internal
fi
xed version, tie to the point of load return. See section on PCB layout guidelines
and evaluation board layout diagram.
Exposed paddle (bottom). Use properly sized vias for thermal coupling to the ground plane. See section
on PCB layout guidelines.
12
EP
SGND
Pin Configuration
TDFN33-12
(Top View)
PGND
LX
VP
VCC
VLDO
OUT
1
2
3
4
5
6
12
11
10
9
8
7
SGND
FB
EN
ENLDO
GND
POK
2
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
202018B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • March 19, 2013
DATA SHEET
AAT2505
Dual Channel, Step-Down Converter/Linear Regulator
Absolute Maximum Ratings
1
Symbol
V
P
, V
LDO
V
LX
V
FB
V
EN
T
J
T
LEAD
Description
Input Voltages to GND
Lx to GND
FB to GND
EN to GND
Operating Junction Temperature Range
Maximum Soldering Temperature (at leads, 10 sec)
Value
6.0
-0.3 to V
P
+ 0.3
-0.3 to V
P
+ 0.3
-0.3 to 6.0
-40 to 150
300
Units
V
V
V
V
°C
°C
Thermal Information
Symbol
P
D
JA
Description
Maximum Power Dissipation
Thermal Resistance
2
Value
2.0
50
Units
W
°C/W
1. Stresses above those listed in Absolute Maximum Ratings may cause permanent damage to the device. Functional operation at conditions other than the operating conditions
specified is not implied. Only one Absolute Maximum Rating should be applied at any one time.
2. Mounted on an FR4 board with exposed paddle connected to ground plane.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
202018B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • March 19, 2013
3
DATA SHEET
AAT2505
Dual Channel, Step-Down Converter/Linear Regulator
Electrical Characteristics
1
V
IN
= V
LDO
= V
OUT(NOM)
+ 1V for V
OUT
options greater than 1.5V. V
IN
= V
LDO
= 2.5V for V
OUT
≤
1.5V. I
OUT
= 1mA, C
OUT
=
2.2μF, C
IN
= 1μF, T
A
= -40°C to +85°C, unless otherwise noted. Typical values are T
A
= 25°C.
Symbol
LDO
V
OUT
V
IN
V
DO
V
OUT
/
V
OUT
* V
IN
V
OUT(Line)
V
OUT(Load)
I
OUT
I
SC
I
QLDO
V
POK
V
POKHYS
V
POK(OL)
I
POK
I
SHDN
PSRR
T
SD
T
HYS
e
N
T
C
Output Voltage Tolerance
Input Voltage
Dropout Voltage
3, 4
Line Regulation
Dynamic Line Regulation
Dynamic Load Regulation
Output Current
Short-Circuit Current
LDO Quiescent Current
POK Trip Threshold
POK Hysteresis
POK Output Voltage Low
POK Output Leakage Current
Shutdown Current
Power Supply Rejection Ratio
Over-Temperature Shutdown Threshold
Over-Temperature Shutdown Hysteresis
Output Noise
Output Voltage Temperature Coefficient
I
SINK
= 1mA
V
POK
< 5.5V, V
OUT
in Regulation
V
IN
= 5V; ENLDO = GND, EN = SGND =
PGND
1kHz
10kHz
I
OUT
= 10mA
1MHz
I
OUT
= 300mA
V
IN
= V
OUT
+ 1V to 5V
I
OUT
= 300mA, V
IN
= V
OUT
+ 1V to V
OUT
+ 2V,
T
R
/T
F
= 2μs
I
OUT
= 1mA to 300mA, T
R
<5μs
V
OUT
> 1.3V
V
OUT
< 0.4V
V
IN
= 5V, No Load, ENLDO = V
IN
V
OUT
Rising, T
A
= 25°C
2.5
60
300
1
70
90
94
1.0
0.4
1.0
1.0
65
45
42
145
15
250
22
125
98
I
OUT
= 1mA to 300mA
T
A
= 25°C
T
A
= -40°C to +85°C
-1.5
-2.5
V
OUT
+
V
DO2
400
1.5
2.5
5.5
600
0.09
%
V
mV
%/V
mV
mV
mA
A
μA
% of
V
OUT
% of
V
OUT
V
μA
μA
dB
°C
°C
μV
RMS
ppm/°C
Description
Conditions
Min
Typ
Max
Units
1. The AAT2505 is guaranteed to meet performance specifications over the -40°C to +85°C operating temperature range and is assured by design, characterization, and correla-
tion with statistical process controls.
2. To calculate the minimum LDO input voltage, use the following equation: V
IN(MIN)
= V
OUT(MAX)
+ V
DO(MAX)
, as long as V
IN
2.5V.
3. For V
OUT
< 2.1V, V
DO
= 2.5 - V
OUT
.
4. V
DO
is defined as V
IN
- V
OUT
when V
OUT
is 98% of nominal.
4
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
202018B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • March 19, 2013
DATA SHEET
AAT2505
Dual Channel, Step-Down Converter/Linear Regulator
Electrical Characteristics
1
I
OUT
= 600mA; typical values are T
A
= 25°C, V
IN
= V
CC
= V
P
= 3.6V.
Symbol
Description
Conditions
Min
2.7
V
IN
Rising
Hysteresis
V
IN
Falling
I
OUT
= 0 to 600mA, V
IN
= 2.7V to 5.5V
ENLDO = GND, No Load, 0.6V Adjustable
Version
EN = SGND = PGND, ENLDO = GND
800
0.45
0.40
V
IN
= 5.5V, V
LX
= 0 to V
IN
, EN = SGND =
PGND
V
IN
= 2.7V to 5.5V
0.6V Output, No Load, T
A
= 25°C
0.6V Output
> 0.6V Output
From Enable to Output Regulation
T
A
= 25°C
1.0
591
250
1.0
150
1.4
140
15
2.0
0.1
600
609
0.2
100
1.8
-3.0
0.6
27
3.0
V
IN
70
1.0
Typ
Max
5.5
2.7
Units
V
V
mV
V
%
V
μA
μA
mA
μA
%/V
mV
μA
k
μs
MHz
°C
°C
V
V
μA
Buck Converter
Input Voltage
V
IN
V
UVLO
V
OUT
V
OUT
I
QBUCK
I
SHDN
I
LIM
R
DS(ON)H
R
DS(ON)L
I
LXLK
UVLO Threshold
Output Voltage Tolerance
Output Voltage Range
Step-Down Converter Quiescent Cur-
rent
Shutdown Current
P-Channel Current Limit
High Side Switch On Resistance
Low Side Switch On Resistance
LX Leakage Current
V
Linereg
Line Regulation
V
FB
FB Threshold Voltage Accuracy
I
FB
FB Leakage Current
R
FB
FB Impedance
T
S
Start-Up Time
F
OSC
Oscillator Frequency
T
SD
Over-Temperature Shutdown Threshold
T
HYS
Over-Temperature Shutdown Hysteresis
Logic Signals
V
EN(L)
Enable Threshold Low
V
EN(H)
Enable Threshold High
I
EN(H)
Leakage Current
0.6
1.4
-1.0
1.0
1. The AAT2505 is guaranteed to meet performance specifications over the -40°C to +85°C operating temperature range and is assured by design, characterization, and correla-
tion with statistical process controls.
Skyworks Solutions, Inc. • Phone [781] 376-3000 • Fax [781] 376-3100 • sales@skyworksinc.com • www.skyworksinc.com
202018B • Skyworks Proprietary Information • Products and Product Information are Subject to Change Without Notice. • March 19, 2013
5
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