PRODUCT DATASHEET
AAT2786
TM
SystemPower
1.5A Step-Down Converter and 150mA LDO
General Description
Features
The AAT2786 is a dual output power solution. It includes
a 1.5A, 1.4MHz, high-efficiency step-down converter and
a high performance 150mA LDO regulator. The step-
down regulator output voltage is adjustable from 0.6V to
VIN. The LDO regulator has a factory preset fixed output
voltage from 1.2V to 3.3V.
• VIN Range : 2.5V to 5.5V
• 1.5A Step-Down Converter
VOUT Range: 0.6V to VIN
95% Peak Efficiency
High Efficiency across load range
42µA No Load Quiescent Current
Optional “PWM Only” Low Noise Mode
Current limit and soft start
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The step-down converter consumes only 42µA of no-load
quiescent current and is designed to maintain high effi-
ciency throughout the load range. The step-down con-
verter has ultra-low RDS(ON) integrated MOSFETs and can
operate up to 100% duty cycle to enable high output
voltage, high current applications which require a low
dropout threshold. The AAT2786 provides excellent tran-
sient response and high output accuracy across the
operating range. Pulling the MODE/SYNC pin high
enables “PWM Only” mode, maintaining constant fre-
quency and low output ripple across the operating range.
Alternatively, the converter may be synchronized to an
external clock input via the MODE/SYNC pin.
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• 150mA LDO Regulator
VOUT Range: 1.2V to 3.3V (Fixed)
High Power Supply Rejection Ratio
Low Output Noise
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• Independent Enable Pins
• Integrated Power MOSFETs
• Over-Temperature Protection
• TDFN34-16 Package
• -40°C to +85°C Temperature Range
Applications
The MicroPower low dropout linear regulator in the
AAT2786 has been specifically designed for high-speed
turn-onandturn-offperformance,fasttransientresponse,
and good noise and power supply ripple rejection (PSRR),
making it ideal for powering sensitive circuits with fast
switching requirements.
• Cellular and Smart Phones
• PDAs, Palmtops
• Digital Still and Video Cameras
• Portable Instruments
• Battery-Powered Applications
Over-temperature and short-circuit protection safeguard
the AAT2786 and system components from damage.
Typical Application
U1
L1
3.3µH
16
1
BUCK IN
BUCK OUT
VP
VP
VIN
LX
LX
FB
R1
15
12
2
5
R2
Adj
C5
100
C4
22µF
Opt
C1
opt
C2
10µF
AAT2786IRN
C3
1µF
R3
59k
13
14
BUCK_EN
ON/OFF
ON/OFF
4
6
GND
MODE/SYNC
11
9
LDO IN
LDOIN
LDO_OUT
LDO OUT
ON/OFF
LDO_EN
BYP
C6
1µF
8
3
7
PGND
C7
2.2µF
C8
10nF
10
LDO_GND
N/C
w w w . a n a l o g i c t e c h . c o m
2786.2008.04.1.0
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