AAT2510
Dual 400mA, 1MHz Step-Down DC-DC Converter
2510.2005.09.1.6
1
SysPwr
TM
General Description
The AAT2510 is a member of AnalogicTech's Total
Power Management ICTM (TPMICTM) product fam-
ily. It is comprised of two 1MHz step-down con-
verters designed to minimize external component
size and cost. The input voltage ranges from 2.7V
to 5.5V. The output voltage ranges from 0.6V to the
maximum applied input voltage and is either fixed
or externally adjustable.
Peak current mode control with internal compensa-
tion provides a stable converter with low ESR ceram-
ic output capacitors for extremely low output ripple.
Each channel has a low 25A quiescent operating
current, which is critical for maintaining high effi-
ciency at light load.
For maximum battery life, each converter's high-
side P-channel MOSFET conducts continuously
when the input voltage approaches dropout (100%
duty cycle operation).
Both regulators have independent input and
enable inputs.
The AAT2510 is available in a thermally-enhanced
12-pin TDFN33 package, and is rated over the -40C
to +85C temperature range.
Features
Up to 96% Efficiency
25A Quiescent Current Per Channel
V
IN
Range: 2.7V to 5.5V
Fixed V
OUT
Range: 0.6V to V
IN
Adjustable V
OUT
Range: 0.6V to 2.5V
Output Current: 400mA
Low R
DS(ON)
0.4
Integrated Power Switches
Low Drop Out 100% Duty Cycle
1.0MHz Switching Frequency
Shutdown Current <1A
Current Mode Operation
Internal Reference Soft Start
Short-Circuit Protection
Over-Temperature Protection
3mm x 3mm, < 1mm high
TDFN33-12 Package
-40C to +85C Temperature Range
Applications
Cellular Phones
Digital Cameras
Handheld Instruments
Microprocessor/DSP Core/IO Power
PDAs and Handheld Computers
Portable Media Players
Typical Application
AAT2510 Efficiency
Load Current (mA)
Efficiency (%)
60
65
70
75
80
85
90
95
100
0.1
1
10
100
1000
2.5V
1.8V
V
IN
= 3.3V with unloaded output disabled
4.7
H
L1
4.7
F
C1
2.5V at 400mA
4.7
H
L2
4.7
F
C2
1.8V at 400mA
10
F
C3
V
IN
= 2.7 - 5.5V
0.1
F
C8
FB1
2
EN1
1
LX1
11
GND2
7
LX2
8
GND1
10
SGND1
3
VIN1
12
VIN2
9
SGND2
6
FB2
5
EN2
4
AAT2510
U1
L1,L2 Sumida CDRH3D16-4R7 C1,C2 Murata GRM219R61A475KE19
C3 Murata GRM21BR60J106KE19
Pin Descriptions
Pin Configuration
TDFN33-12
(Top View)
EN1
FB1
SGND1
1
EN2
FB2
SGND2
VIN1
LX1
GND1
VIN2
LX2
GND2
2
3
4
5
6
12
11
10
9
8
7
Pin #
Symbol
Function
1, 4
EN1, EN2
Converter enable input. A logic high enables the converter channel. A logic low
forces the channel into shutdown mode, reducing the channel supply current to less
than 1A. This pin should not be left floating. When not actively controlled, this pin
can be tied directly to the source voltage (VIN1, VIN2).
2, 5
FB1, FB2
Feedback input pin. For fixed output voltage versions, this pin is connected to the
converter output, forcing the converter to regulate to the specified voltage. For
adjustable versions, an external resistive divider ties to this point and programs the
output voltage to the desired value.
3, 6
SGND1, SGND2
Signal ground. For external feedback, return the feedback resistive divider to this
ground. For internal fixed version, tie to the point of load return. See section on PCB
layout guidelines and evaluation board layout diagram.
7, 10
GND2, GND1
Main power ground return. Connect to the input and output capacitor return. See sec-
tion on PCB layout guidelines and evaluation board layout diagram.
8, 11
LX2, LX1
Output switching node that connects to the respective output inductor.
9, 12
VIN2, VIN1
Input supply voltage. Must be closely decoupled to the respective power gnd.
EP
Exposed paddle (bottom). Use properly sized vias for thermal coupling to the ground
plane. See section on PCB layout guidelines.
AAT2510
Dual 400mA, 1MHz Step-Down DC-DC Converter
2
2510.2005.09.1.6
Absolute Maximum Ratings
1
Thermal Information
Symbol
Description
Value
Units
P
D
Maximum Power Dissipation
2
W
JA
Thermal Resistance
2
50
C/W
Symbol
Description
Value
Units
V
IN
VIN1, VIN2 to SGND1, SGND2, GND1, and GND2
6.0
V
V
LX
LX1, LX2 to GND1, GND2
-0.3 to V
P
+ 0.3
V
V
FB
FB1 and FB2 to SGND1, SGND2, GND1, and GND2
-0.3 to V
P
+ 0.3
V
V
EN
EN1 and EN2 to SGND1, SGND2, GND1, and GND2
-0.3 to 6.0
V
T
J
Operating Junction Temperature Range
-40 to 150
C
T
LEAD
Maximum Soldering Temperature (at leads, 10 sec)
300
C
AAT2510
Dual 400mA, 1MHz Step-Down DC-DC Converter
2510.2005.09.1.6
3
1. Stresses above those listed in Absolute Maximum Ratings may cause permanent damage to the device. Functional operation at condi-
tions 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.
Electrical Characteristics
1
T
A
= -40C to 85C, unless otherwise noted. Typical values are T
A
= 25C, V
IN
= 3.6V.
Symbol
Description
Conditions
Min
Typ
Max
Units
Step-Down Converter Channels
V
IN
Input Voltage
2.7
5.5
V
V
IN
Rising
2.6
V
V
UVLO
UVLO Threshold
Hysteresis
100
mV
V
IN
Falling
1.8
V
V
OUT
Output Voltage Tolerance
I
OUT
= 0 to 400mA, V
IN
= 2.7 - 5.5V
-3.0
+3.0
%
V
OUT
Output Voltage Range
Fixed Output Version
0.6
4.0
V
Adjustable Output Version
2
0.6
2.5
I
Q
Quiescent Current
No Load, 0.6V Adjustable Version,
25
50
A
Per Channel
I
SHDN
Shutdown Current
EN = SGND = GND
1.0
A
I
LIM
P-Channel Current Limit
600
mA
R
DS(ON)H
High Side Switch On Resistance
0.45
R
DS(ON)L
Low Side Switch On Resistance
0.4
I
LXLK
LX Leakage Current
V
IN
= 5.5V, V
LX
= 0 to V
IN
,
1
A
EN = SGND = GND
V
Linereg
Line Regulation
V
IN
= 2.7V to 5.5V
0.2
%/V
V
FB
FB Threshold Voltage Accuracy
0.6V Output, No Load, T
A
= 25C
597
600
615
mV
I
FB
FB Leakage Current
0.6V Output
0.2
A
R
FB
FB Impedance
>0.6V Output
250
k
F
OSC
Oscillator Frequency
T
A
= 25C
0.7
1.0
1.5
MHz
T
SD
Over-Temperature Shutdown
140
C
Threshold
T
HYS
Over-Temperature Shutdown
15
C
Hysteresis
EN
V
EN(L)
Enable Threshold Low
0.6
V
V
EN(H)
Enable Threshold High
1.4
V
I
EN
Input Low Current
V
IN
= V
FB
= 5.5V
-1.0
1.0
A
AAT2510
Dual 400mA, 1MHz Step-Down DC-DC Converter
4
2510.2005.09.1.6
1. The AAT2510 is guaranteed to meet performance specifications over the -40C to +85C operating temperature range and is assured
by design, characterization, and correlation with statistical process controls.
2. For adjustable version with higher than 2.5V output, please consult your AnalogicTech representative.
Typical Channel Characteristics
Output Voltage Error vs. Temperature
(V
IN
= 3.6V; V
O
= 1.5V)
Temperature (
C)
Output Error (%)
-2.0
-1.0
0.0
1.0
2.0
-40
-20
0
20
40
60
80
100
Frequency vs. Input Voltage
(V
OUT
= 1.8V)
Input Voltage (V)
Frequency Variation (%)
-2.0
-1.5
-1.0
-0.5
0.0
0.5
1.0
2.7
3.1
3.5
3.9
4.3
4.7
5.1
5.5
DC Regulation
(V
OUT
= 1.8V; L = 4.7
H)
Output Current (mA)
Output Error (%)
-2.0
-1.0
0.0
1.0
2.0
0.1
1.0
10
100
1000
V
IN
= 2.7V
V
IN
= 3.6V
V
IN
= 4.2V
Efficiency vs. Load
(V
OUT
= 1.8V; L = 4.7
H)
Output Current (mA)
E
ff
iciency
(%)
50
60
70
80
90
100
0.1
1.0
10
100
1000
V
IN
= 2.7V
V
IN
= 3.6V
V
IN
= 4.2V
Load Regulation
(V
OUT
= 2.5V; L = 4.7
H)
Output Current (mA)
Output Error (%)
-2.0
-1.0
0.0
1.0
2.0
0.1
1.0
10
100
1000
V
IN
= 3.0V
V
IN
= 3.3V
V
IN
= 3.6V
Efficiency vs. Load
(V
OUT
= 2.5V; L = 4.7
H)
Output Current (mA)
Efficiency (%)
60
70
80
90
100
0.1
1.0
10
100
1000
V
IN
= 3.3V
V
IN
= 3.6V
V
IN
= 3.0V
AAT2510
Dual 400mA, 1MHz Step-Down DC-DC Converter
2510.2005.09.1.6
5
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