1MHz 700mA Step-Down DC-DC Converter
General Description
The AAT1156 SwitchReg is a step-down switching
converter ideal for applications where high efficien-
cy is required over the full range of load conditions.
The 2.7V to 5.5V input voltage range makes the
AAT1156 ideal for single-cell lithium-ion/polymer
battery applications. Capable of more than 700mA
with internal MOSFETs, the current-mode con-
trolled IC provides high efficiency over a wide oper-
ating range. Fully integrated compensation simpli-
fies system design and lowers external parts count.
The AAT1156 is available in a Pb-free, 16-pin,
3x3mm QFN package and is rated over the -40°C
to +85°C temperature range.
AAT1156
Features
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SwitchReg
™
V
IN
Range: 2.7V to 5.5V
Up to 95% Efficiency
110mΩ R
DS(ON)
Internal Switches
<1μA Shutdown Current
1MHz Step-Down Switching Frequency
Fixed or Adjustable V
OUT
≥
0.8V
Integrated Power Switches
Current Mode Operation
Internal Compensation
Stable with Ceramic Capacitors
Internal Soft Start
Over-Temperature Protection
Current Limit Protection
16-Pin QFN 3x3mm Package
-40°C to +85°C Temperature Range
Applications
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Cellular Phones
Digital Cameras
MP3 Players
Notebook Computers
PDAs
Wireless Notebook Adapters
Typical Application
U1
AAT1156
VP
R1
100
C1
10μF
VP
VP
EN
VCC
LL
C2
0.1
μF
NC
SGND
FB
LX
LX
LX
NC
PGND
PGND
PGND
R4
59k
C3, C4
2 x 22μF
L1
4.7μH
R3
187k
Efficiency vs. Load Current
2.5V
100
95
INPUT
(V
OUT
= 2.5V; L = 4.7µH)
V
IN
= 3.0V
V
IN
= 4.2V
V
IN
= 3.6V
Efficiency (%)
90
85
80
75
70
65
60
55
50
1
10
100
1000
C1 Murata 10μF 6.3V X5R GRM42-6X5R106K6.3
C3-C4 MuRata 22μF 6.3V GRM21BR60J226ME39L X5R 0805
L1 Sumida CDRH3D16-4R7NC
Output Current (mA)
1156.2007.01.1.4
1
ANALOGICTECH [ ADVANCED ANALOGIC TECHNOLOGIES ]
