AAT1156
1MHz 700mA Step-Down DC-DC Converter
1156.2005.11.1.2 1
SwitchReg
™
General Description
The AAT1156 SwitchReg™ is a member of
AnalogicTech™'s Total Power Management IC™
(TPMIC™) product family. The step-down switching
converter is ideal for applications where high effi-
ciency is required over the full range of load condi-
tions. 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 the 16-pin 3x3mm
QFN package and is rated over the -40°C to +85°C
temperature range.
Features
•V
IN
Range: 2.7 to 5.5 Volts
• 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
• Cellular Phones
• Digital Cameras
• MP3 Players
• Notebook Computers
• PDAs
• Wireless Notebook Adapters
Typical Application
AAT1156 Efficiency
(V
OUT
= 2.5V; L = 4.7µH; CDRH3D16)
Output Current (mA)
Efficiency (%)
50
55
60
65
70
75
80
85
90
95
100
1 10 100 1000
V
IN
= 3.0V
V
IN
= 3.6V
V
IN
= 4.2V
4.7µH
L1
2 x 22µF
C3, C4
10µF
C1
100
R1
0.1 µF
C2
C1 Murata 10µF 6.3V X5R GRM42-6X5R106K6.3
C3-C4 MuRata 22µF 6.3V GRM21BR60J226ME39L X5R 0805
2.5VINPUT
L1 Sumida CDRH3D16-4R7NC
187k
R3
59k
R4
LX
14
LL
6
EN
7
VCC
9
VP
10
NC
8
LX
13
PGND
3
VP
12
VP
11
FB
4
LX
15
PGND
2
PGND
1
SGND
5
NC
16
AAT1156
U1