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AOZ1051PI
EZBuck™ 3 A Synchronous Buck Regulator
General Description
The AOZ1051PI is a high efficiency, easy to use, 3 A
synchronous buck regulator. The AOZ1051PI works from
4.5 V to 18 V input voltage range, and provides up to 3 A
of continuous output current with an output voltage
adjustable down to 0.8 V.
The AOZ1051PI comes in an exposed pad SO-8
package and is rated over a -40 °C to +85 °C operating
ambient temperature range.
Features
z 4.5 V to 18 V operating input voltage range
z Synchronous Buck: 70 minternal high-side switch
and 40 minternal low-side switch (at 12 V)
z Up to 95 % efficiency
z External soft start
z Output voltage adjustable to 0.8 V
z 3 A continuous output current
z 500 kHz PWM operation
z Cycle-by-cycle current limit
z Pre-bias start-up
z Short-circuit protection
z Thermal shutdown
z Exposed pad SO-8 package
Applications
z Point of load DC/DC converters
z LCD TV
z Set top boxes
z DVD and Blu-ray players/recorders
z Cable modems
Typical Application
VIN
C1
10µF
RC
CC
CSS
VIN SS
EN
AOZ1051PI LX
COMP
FB
AGND
PGND
L1 4.7µH
R1
R2
VOUT
C2, C3
22µF
Rev. 1.0 June 2011
Figure 1. 3.3 V 3 A Synchronous Buck Regulator, Fs = 500 kHz
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Ordering Information
Part Number
AOZ1051PI
Ambient Temperature Range
-40 °C to +85 °C
Package
EPAD SO-8
AOS Green Products use reduced levels of Halogens, and are also RoHS compliant.
Please visit www.aosmd.com/web/quality/rohs_compliant.jsp for additional information.
Pin Configuration
PGND 1
VIN 2
AGND 3
FB 4
PAD
(LX)
8 NC
7 SS
6 EN
5 COMP
Exposed Pad SO-8
(Top View)
AOZ1051PI
Environmental
Green Product
Pin Description
Pin Number
1
2
Pin Name
PGND
VIN
3 AGND
4 FB
5 COMP
6 EN
7 SS
8 NC
Exposed pad
LX
Pin Function
Power ground. PGND needs to be electrically connected to AGND.
Supply voltage input. When VIN rises above the UVLO threshold and EN is logic high,
the device starts up.
Analog ground. AGND is the reference point for controller section. AGND needs to be
electrically connected to PGND.
Feedback input. The FB pin is used to set the output voltage via a resistive voltage divider
between the output and AGND.
External loop compensation pin. Connect a RC network between COMP and AGND to
compensate the control loop.
Enable pin. Pull EN to logic high to enable the device. Pull EN to logic low to disable the
device. If on/off control in not needed, connect EN to VIN and do not leave it open.
Soft-start pin. 5 µA current charging current.
No Connect Pin. Pin 8 is not internally connected. Connect this pin externally to LX and
use it for better thermal performance.
Switching node. LX is the drain of the internal PFET. LX is used as the thermal pad of the
power stage.
Rev. 1.0 June 2011
www.aosmd.com
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Block Diagram
AOZ1051PI
VIN
EN
UVLO
5V LDO
Internal
OTP
& POR
Regulator
+5V
Reference
& Bias
Softstart
SS
0.8V
FB
SS
5µA
+
EAmp
COMP
+
PWM
Comp
+
ILimit
PWM
Control
Logic
500kHz
Oscillator
+
ISen
Level
Shifter
+
FET
Driver
Q1
Q2
LX
AGND
PGND
Absolute Maximum Ratings
Exceeding the Absolute Maximum Ratings may damage the
device.
Parameter
Supply Voltage (VIN)
LX to AGND
LX to AGND (20 ns)
EN to AGND
FB, SS, COMP to AGND
PGND to AGND
Junction Temperature (TJ)
Storage Temperature (TS)
ESD Rating(1)
Rating
20 V
-0.7 V to VIN+0.3 V
-5 V to 22 V
-0.3 V to VIN+0.3 V
-0.3 V to 6.0 V
-0.3 V to +0.3 V
+150 °C
-65 °C to +150 °C
2.0 kV
Note:
1. Devices are inherently ESD sensitive, handling precautions are
required. Human body model rating: 1.5 kin series with 100 pF.
Recommended Operating Conditions
The device is not guaranteed to operate beyond the Maximum
Recommended Operating Conditions.
Parameter
Rating
Supply Voltage (VIN)
Output Voltage Range
Ambient Temperature (TA)
Package Thermal Resistance
Exposed Pad SO-8 (ΘJA)(2)
4.5 V to 18 V
0.8 V to 0.85 • VIN
-40 °C to +85 °C
50 °C/W
Note:
2. The value of ΘJA is measured with the device mounted on a 1-in2
FR-4 board with 2 oz. Copper, in a still air environment with
TA = 25 °C. The value in any given application depends on the
user’s specific board design.
Rev. 1.0 June 2011
www.aosmd.com
Page 3 of 14
Free Datasheet http://www.datasheet4u.com/