AAT2786 Datasheet, PDF (1/27 Pages) Advanced Analogic Technologies – 1.5A Step-Down Converter and 150mA LDO

SystemPower^TM
PRODUCT DATASHEET
AAT2786
1.5A Step-Down Converter and 150mA LDO
General Description
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
V_IN. The LDO regulator has a factory preset fixed output
voltage from 1.2V to 3.3V.
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 R_DS(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.
The MicroPower low dropout linear regulator in the
AAT2786 has been specifically designed for high-speed
turn-on and turn-off performance, fast transient response,
and good noise and power supply ripple rejection (PSRR),
making it ideal for powering sensitive circuits with fast
switching requirements.
Over-temperature and short-circuit protection safeguard
the AAT2786 and system components from damage.
Features
• V_IN 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
• 150mA LDO Regulator
▪ VOUT Range: 1.2V to 3.3V (Fixed)
▪ ^{High Power Supply Rejection Ratio}
▪ Low Output Noise
• Independent Enable Pins
• Integrated Power MOSFETs
• Over-Temperature Protection
• TDFN34-16 Package
• -40°C to +85°C Temperature Range
Applications
• Cellular and Smart Phones
• PDAs, Palmtops
• Digital Still and Video Cameras
• Portable Instruments
• Battery-Powered Applications
Typical Application
BUCK IN
C1
opt
R1
100
C2
10µF
C3
1µF
U1
L1
16 _VP
15 _VP
LX ¹
3.3µH
LX ²
R2
Adj
12 _VIN
FB ⁵
AAT2786IRN
R3
ON/OFF ¹³ BUCK_EN
GND ⁴
59k
ON/OFF ^{14 MODE/SYNC}
LDO IN
11 _{LDOIN LDO_OUT} 6
ON/OFF
C6
1µF
9 _{LDO_EN}
8 _BYP
PGND ³
C8
10nF ¹⁰ N/C
LDO_GND ⁷
BUCK OUT
C5
Opt C4
22µF
LDO OUT
C7
2.2µF
2786.2008.04.1.0
www.analogictech.com
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