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AOZ1210
EZBuck™ 2A Simple Buck Regulator
General Description
The AOZ1210 is a high efficiency, simple to use, 2A buck
regulator flexible enough to be optimized for a variety of
applications. The AOZ1210 works from a 4.5V to 27V
input voltage range, and provides up to 2A of continuous
output current on each buck regulator output. The output
voltage is adjustable down to 0.8V.
Features
●
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4.5V to 27V operating input voltage range
70m
Ω
internal NFET, efficiency: up to 95%
Internal soft start
Output voltage adjustable down to 0.8V
2A continuous output current
Fixed 370kHz PWM operation
Cycle-by-cycle current limit
Short-circuit protection
Thermal shutdown
Small size SO-8 packages
Applications
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Point of load DC/DC conversion
Set top boxes
DVD drives and HDD
LCD Monitors & TVs
Cable modems
Telecom/Networking/Datacom equipment
Typical Application
VIN
C1
22µF
C7
VIN
EN
BS
LX
L1
6.8µH
VOUT
AOZ1210
VBIAS
C4
R1
FB
GND
R2
C4, C6
22µF
COMP
R
C
C
C
Figure 1. 3.3V/2A Buck Regulator
Rev. 1.3 December 2007
www.aosmd.com
Page 1 of 14
AOZ1210
Ordering Information
Part Number
AOZ1210AI
Ambient Temperature Range
-40°C to +85°C
Package
SO-8
Environmental
RoHS
All AOS Products are offering in packaging with Pb-free plating and compliant to RoHS standards.
Please visit
www.aosmd.com/web/quality/rohs_compliant.jsp
for additional information.
Pin Configuration
LX
BST
GND
FB
1
2
3
4
8
7
6
5
VBIAS
VIN
EN
COMP
SO-8
(Top View)
Pin Description
Pin Number
1
2
3
4
5
6
7
8
Pin Name
LX
BST
GND
FB
COMP
EN
V
IN
VBIAS
Pin Function
PWM output connection to inductor. LX pin needs to be connected externally. Thermal connection
for output stage.
Bootstrap voltage input. High side driver supply. Connected to 0.1µF capacitor between BST and
LX.
Ground.
Feedback input. It is regulated to 0.8V. The FB pin is used to determine the PWM output voltage
via a resistor divider between the output and GND.
External loop compensation. Output of internal error amplifier. Connect a series RC network to
GND for control loop compensation.
Enable pin. The enable pin is active HIGH. Connect EN pin to V
IN
if not used. Do not leave the EN
pin floating.
Supply voltage input. Range from 4.5V to 27V. When V
IN
rises above the UVLO threshold the
device starts up. All V
IN
pins need to be connected externally.
Compensation pin of internal linear regulator. Place put a 1µF capacitor between this pin and
ground.
Rev. 1.3 December 2007
www.aosmd.com
Page 2 of 14
AOZ1210
Block Diagram
VIN
VBIAS
+5V
EN
UVLO
& POR
5V LDO
Regulator
OTP
+
ISen
–
Reference
& Bias
Softstart
ILimit
Q1
GM = 200µA/V
+
–
+
BST
0.8V
+
EAmp
FB
–
PWM
Comp
PWM
Control
Logic
LX
COMP
+
0.2V
–
Frequency
Foldback
Comparator
370kHz/24kHz
Oscillator
Q2
GND
Absolute Maximum Ratings
Exceeding the Absolute Maximum Ratings may damage the device.
Recommend Operating Ratings
The device is not guaranteed to operate beyond the Maximum
Operating Ratings.
Parameter
Supply Voltage (V
IN
)
LX to GND
EN to GND
FB to GND
COMP to GND
BST to GND
VBIAS to GND
Junction Temperature (T
J
)
Storage Temperature (T
S
)
ESD Rating: Human Body Model
(1)
Rating
30V
-0.7V to V
IN
+0.3V
-0.3V to V
IN
+0.3V
-0.3V to 6V
-0.3V to 6V
V
LX
+6V
-0.3V to 6V
+150°C
-65°C to +150°C
2kV
Parameter
Supply Voltage (V
IN
)
Output Voltage Range
Ambient Temperature (T
A
)
Package Thermal Resistance SO-8
(Θ
JA
)
(2
)
Rating
4.5V to 27V
0.8V to V
IN
-40°C to +85°C
105°C/W
Note:
2. The value of
Θ
JA
is measured with the device mounted on 1-in
2
FR-4 board with 2oz. Copper, in a still air environment with T
A
= 25°C.
The value in any given application depends on the user's specific
board design.
Note:
1. Devices are inherently ESD sensitive, handling precautions are
required. Human body model rating: 1.5k
Ω
in series with 100pF.
Rev. 1.3 December 2007
www.aosmd.com
Page 3 of 14
AOZ1210
T
A
= 25°C, V
IN
= V
EN
= 12V, V
OUT
= 3.3V unless otherwise specified
(3
)
Electrical Characteristics
Symbol
V
IN
V
UVLO
I
IN
I
OFF
V
FB
Supply Voltage
Parameter
Input Under-Voltage Lockout Threshold
Supply Current (Quiescent)
Shutdown Supply Current
Feedback Voltage
Load Regulation
Line Regulation
V
IN
Rising
V
IN
Falling
Conditions
Min.
4.5
Typ.
4.3
4.1
2
3
Max.
27
Units
V
V
I
OUT
= 0, V
FB
= 1.2V, V
EN
> 2V
V
EN
= 0V
0.782
3
20
0.818
mA
µA
V
%
%/V
0.8
0.5
0.08
I
FB
ENABLE
V
EN
V
HYS
f
O
D
MAX
D
MIN
G
VEA
G
EA
I
LIM
Feedback Voltage Input Current
EN Input Threshold
EN Input Hysteresis
Frequency
Maximum Duty Cycle
Minimum Duty Cycle
Error Amplifier Voltage Gain
Error Amplifier Transconductance
Current Limit
Over-Temperature Shutdown Limit
T
J
Rising
T
J
Falling
V
FB
= 0V
3.5
145
100
24
4
70
V
EN
= 0V, V
LX
= 0V
500
200
315
85
Off Threshold
On Threshold
200
0.6
2.5
200
370
425
6
nA
V
mV
kHz
%
%
V/V
µA / V
MODULATOR
PROTECTION
5.0
A
°C
kHz
ms
100
10
m
Ω
µA
f
SC
t
SS
R
DS(ON)
Short Circuit Hiccup Frequency
Soft Start Interval
High-Side Switch On-Resistance
High-Side Switch Leakage
PWM OUTPUT STAGE
Note:
3. Specification in
BOLD
indicate an ambient temperature range of -40°C to +85°C. These specifications are guaranteed by design.
Rev. 1.3 December 2007
www.aosmd.com
Page 4 of 14
AOZ1210
Typical Performance Characteristics
Circuit of Figure 1. T
A
= 25°C, V
IN
= V
EN
= 24V, V
OUT
= 3.3V unless otherwise specified.
Light Load (DCM) Operation
Vin ripple
0.1V/div
Vo ripple
20mV/div
Full Load (CCM) Operation
Vin ripple
0.1V/div
Vo ripple
20mV/div
IL
1A/div
IL
1A/div
VLX
20V/div
VLX
20V/div
1µs/div
1µs/div
Startup to Full Load
Short Circuit Protection
Vo
2V/div
Vo
2V/div
lin
0.5A/div
lL
2A/div
2ms/div
200µs/div
50% to 100% Load Transient
Short Circuit Recovery
Vo Ripple
200mV/div
Vo
2V/div
lo
1A/div
IL
2A/div
200µs/div
2ms/div
Rev. 1.3 December 2007
www.aosmd.com
Page 5 of 14

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