AME
AME5269
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General Description
The AME5269 is a fixed frequency monolithic synchro-
nous buck regulator that accepts input voltage from 4.75V
to 28V. Two NMOS switches with low on-resistance are
integrated on the die. Current mode topology is used for
fast transient response and good loop stability.
Shutdown mode reduces the input supply current to less
than 1µA. An adjustable soft-start prevents inrush current
at turn-on.
This device is available in SOP-8 package.
2A, 28V, 340KHz Synchronous
Rectified Step-Down Converter
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Features
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2A Output Current
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Wide 4.75V to 28V Operating Input Range
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Integrated Power MOSFET Switches
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Output Adjustable from 0.925V to 25V
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Up to 95% Efficiency
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Programmable Soft Start
l
Stable with Low ESR Ceramic Output
Capacitors
l
Cycle-by Cycle Over Current Protection
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Fixed 340KHz Frequency
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Applications
l
l
l
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Distributed Power System
Networking System
FPGA, DSP, ASIC Power Supplies
Notebook Computers
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Input Under Voltage Lockout
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System Protected by Over-current Limiting,
Over-voltage Protection and Thermal shut
-down
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Green Products Meet RoHS Standards
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Typical Application
V
IN
12V
C1
10µF/35V
x2
R4
100KΩ
EN
C
ie
C5
10nF
L1
15µH
SW
IN
BS
V
OUT
5V
2A
AME5269
SS
GND
FB
COMP
R1
44.2KΩ
S
C2
22µF/10V
x2
C4
0.1µF
C6
(Optional)
C3/3.3nF
R3/6.98KΩ
R2
10KΩ
Rev. B.01
1
AME
AME5269
n
Functional Block Diagram
1.1V
OVDET
2A, 28V, 340KHz Synchronous
Rectified Step-Down Converter
OVP
CURRENT SENSE AMP
FB
0.3V
OSC
CLK
S
Q
SLOPE
VIN
5V
BS
COMP
MH
6uA
PWM
R
LOGIC
SW
0.925V
EA
CLAMP
SS
OVP
ML
OTP
UVLO
OTDET
UVLO
IRCMP
EN
2.5V
1.5V
LOCKOUT CMP
INTERNAL
REGULATORS
SHUTDOWN CMP
IN
GND
2
Rev. B.01
AME
AME5269
n
Pin Configuration
SOP-8
Top View
8
7
6
5
2A, 28V, 340KHz Synchronous
Rectified Step-Down Converter
AME5269-AHAxxx
1. BS
2. IN
3. SW
AME5269
4. GND
5. FB
6. COMP
7. EN
Die Attach:
Conductive Epoxy
1
2
3
4
8. SS
C
ie
Rev. B.01
3
AME
AME5269
n
Pin Description
SOP-8
2A, 28V, 340KHz Synchronous
Rectified Step-Down Converter
Pin Number
1
Pin Name
BS
Pin Description
High-Side Gate Drive Boost Input. BS supplies the drive for the high-side N-
Channel MOSFET switch. Connect a 0.01µF or greater capacitor from SW to
BS to power the high side switch.
Power Input. IN supplies the power to the IC, as well as the step-down
converter switches. Drive IN with a 4.75V to 28V power source. Bypass IN to
GND with a suitable large capacitor to eliminate noise on the input to the IC.
Power Switching Output. SW is the switching node that supplies power to the
output. Connect the output LC filter from SW to the output load. Note that a
capacitor is required from SW to BS to power the high-side switch.
Ground. Connect the exposed pad to pin 4.
Feedback Input. FB senses the output voltage to regulate that voltage. Drive
FB with a resistive voltage divider from the output voltage. The feedback
reference voltage is 0.925V.
Compensation Node. COMP is used to compensate the regulation control
loop. Connect a series RC network from COMP to GND to compensate the
regulation control loop. In some cases, an additional capacitor from COMP to
GND is required.
Enable Input. EN is a digital input that turns the regulator on or off. Drive EN
higher than 2.7V to turn on the regulator, drive it lower than 1.1V to turn it off.
Pull up to the IN pin with 100KΩ resister for automatic start up.
Soft-start Control Input. SS controls the soft-start period. Connect a capacitor
from SS to GND to set the soft-start period. Add a 0.1uF capacitor set the
soft-start period to 15mS. To disable the soft start feature, leave the SS
unconnected.
2
IN
3
4
5
SW
GND
FB
6
COMP
7
EN
8
SS
4
Rev. B.01
AME
AME5269
n
Ordering Information
AME5269 - x x x xxx
2A, 28V, 340KHz Synchronous
Rectified Step-Down Converter
Output Voltage
Number of Pins
Package Type
Pin Configuration
Pin Configuration
Package
Type
H: SOP
Number of
Pins
A: 8
Output Voltage
A
(SOP-8)
1. BS
2. IN
3. SW
4. GND
5. FB
6. COMP
7. EN
8. SS
ADJ: Adjustable
C
ie
Rev. B.01
5
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