MP9447
High-Efficiency, Fast-Transient, 5A, 36V
Synchronous, Step-Down Converter
The Future of Analog IC Technology
DESCRIPTION
The MP9447 is a fully-integrated, high-
frequency, synchronous, rectified, step-down,
switch-mode converter. It offers a very compact
solution to achieve a 5A, continuous-output
current over a wide input-supply range with
excellent load and line regulation. It also
provides fast transient response and good
stability for wide input-supply and load range.
The MP9447 operates at high efficiency over a
wide output current load range.
Full protection features include SCP, OCP, UVP,
and thermal shutdown.
The MP9447 requires a minimal number of
readily-available, standard, external components,
and is available in a space-saving 3mm×4mm,
20-pin, QFN package.
FEATURES
Wide 4.5V-to-36V Operating Input Range
Guaranteed 5A, Continuous Output Current
Internal 65mΩ High-Side, 30mΩ Low-Side
Power MOSFETs
Proprietary Switching-Loss-Reduction
Technology
1.5% Reference Voltage
Programmable Soft-Start Time
Low Drop-out Mode
200kHz-to-650kHz Switching Frequency
SCP, OCP, UVP, and Thermal Shutdown
Output Adjustable from 0.8V to 0.9×V
IN
Available in a 3×4mm 20-pin QFN Package
General Consumer
USB Power Supplies
Cigarette Lighter Adapters
Power Supply for Chargers
APPLICATIONS
All MPS parts are lead-free and adhere to the RoHS directive. For MPS green
status, please visit MPS website under Quality Assurance.
“MPS” and “The Future of Analog IC Technology” are Registered Trademarks of
Monolithic Power Systems, Inc.
TYPICAL APPLICATION
MP9447 Rev. 1.2
1/5/2016
www.MonolithicPower.com
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
© 2016 MPS. All Rights Reserved.
1
MP9447–HIGH-EFFICIENCY, FAST-TRANSIENT, SYNCHRONOUS, STEP-DOWN CONVERTER
ORDERING INFORMATION
Part Number*
MP9447GL
Package
QFN-20 (3mm×4mm)
Top Marking
See Below
*
For Tape & Reel, add suffix –Z (e.g. MP9447GL–Z)
TOP MARKING
\
9447: product code of MP9447GL;
MP: MPS prefix;
Y: year code;
W: week code:
LLL: lot number;
PACKAGE REFERENCE
TOP VIEW
VCC IN
20
AGND
FREQ
FB
SS
EN
NC
1
2
3
4
5
6
7
19
21
IN
24
SW
22
IN
25
SW
23
IN
8
9
10
SW SW
18
17
16
15
14
13
12
11
PGND
PGND
PGND
PGND
PGND
PGND
BST IN SW SW
EXPOSED PAD
ON BACKSIDE
QFN20 (3×4mm)
MP9447 Rev. 1.2
1/5/2016
www.MonolithicPower.com
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
© 2016 MPS. All Rights Reserved.
2
MP9447–HIGH-EFFICIENCY, FAST-TRANSIENT, SYNCHRONOUS, STEP-DOWN CONVERTER
(4)
ABSOLUTE MAXIMUM RATINGS
(1)
Supply Voltage V
IN
....................................... 40V
V
SW
........................................-0.3V to V
IN
+ 0.3V
V
BST
...................................................... V
SW
+ 6V
All Other Pins ..................................-0.3V to +6V
(2)
Continuous Power Dissipation (T
A
= +25°C)
………………………………… …………….2.6W
Operating Junction Temperature ..............150°C
Lead Temperature ....................................260°C
Storage Temperature............... -65°C to +150°C
Thermal Resistance
θ
JA
θ
JC
QFN-20 (3mm×4mm)..............48 ...... 10 ... °C/W
Notes:
1) Exceeding these ratings may damage the device.
2) The maximum allowable power dissipation is a function of the
maximum junction temperature T
J
(MAX), the junction-to-
ambient thermal resistance
θ
JA
, and the ambient temperature
T
A
. The maximum allowable continuous power dissipation at
any ambient temperature is calculated by P
D
(MAX)=(T
J
(MAX)-
T
A
)/θ
JA
. Exceeding the maximum allowable power dissipation
will cause excessive die temperature, and the regulator will go
into thermal shutdown. Internal thermal shutdown circuitry
protects the device from permanent damage.
3) The device is not guaranteed to function outside of its
operating conditions.
4) Measured on JESD51-7, 4-layer PCB.
Recommended Operating Conditions
(3)
Supply Voltage V
IN
...........................4.5V to 36V
Output Voltage V
OUT
................... 0.8V to 0.9×V
IN
Operating Junction Temp. (T
J
). -40°C to +125°C
MP9447 Rev. 1.2
1/5/2016
www.MonolithicPower.com
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
© 2016 MPS. All Rights Reserved.
3
MP9447–HIGH-EFFICIENCY, FAST-TRANSIENT, SYNCHRONOUS, STEP-DOWN CONVERTER
ELECTRICAL CHARACTERISTICS
V
IN
= 24V, V
EN
= 2V, T
A
= +25°C, unless otherwise noted.
Parameters
Supply Current (Shutdown)
Supply Current (Quiescent)
HS Switch On Resistance
LS Switch On Resistance
(5)
Switch Leakage
Current Limit
One-Shot On Time
Minimum Off Time
(5)
Foldback Off Time
(5)
Foldback Off Time
(5)
OCP Hold-Off Time
(5)
Feedback Voltage
Feedback Current
Soft-Start Charging Current
EN Rising Threshold
EN Falling Threshold
EN Threshold Hysteresis
EN Input Current
V
IN
Under-Voltage Lockout
Threshold Rising
V
IN
Under-Voltage Lockout
Threshold Hysteresis
V
CC
Regulator
V
CC
Load Regulation
Thermal Shutdown
(5)
Thermal Shutdown Hysteresis
(5)
Symbol
I
IN
I
IN
HS
RDS-ON
LS
RDS-ON
SW
LKG
I
LIMIT
t
ON
t
OFF
t
FB
t
FB
t
OC
V
FB
I
FB
I
SS
EN
Vth-Hi
EN
Vth-Lo
EN
Vth-Hys
I
EN
INUV
Vth
INUV
HYS
V
CC
T
SD
T
SD-HYS
I
CC
=0
I
CC
=10mA
4.5
I
LIM
=1(HIGH),
V
FB
>50%V
REF
I
LIM
=1(HIGH),
V
FB
<50%V
REF
I
LIM
=1(HIGH)
803
V
FB
= 815mV
V
SS
=0V
6
1.0
0.7
V
IN
=12V,
R
FREQ
=30kΩ
Condition
V
EN
= 0V
V
FB
= 0.95V
Min
Typ
10
500
65
30
10
6
230
8
280
100
4.8
16.8
100
815
10
8.5
1.25
0.86
390
1.5
4.0
880
4.85
1
165
25
5.2
827
50
11
1.4
0.92
2
4.3
330
Max
200
600
75
200
Units
nA
μA
mΩ
mΩ
nA
A
ns
ns
μs
μs
μs
mV
nA
μA
V
V
mV
μA
V
mV
V
%
°C
°C
V
EN
= 0V
V
SW
= 0V or 36V
V
EN
= 2V
3.7
Note:
5) Derived from bench characterization, not tested in production.
MP9447 Rev. 1.2
1/5/2016
www.MonolithicPower.com
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
© 2016 MPS. All Rights Reserved.
4
MP9447–HIGH-EFFICIENCY, FAST-TRANSIENT, SYNCHRONOUS, STEP-DOWN CONVERTER
TYPICAL PERFORMANCE CHARACTERISTICS
V
IN
= 24V, V
OUT
= 3.3V, L = 10µH, T
A
= +25°C, unless otherwise noted.
Efficiency vs.
Load Current
100
90
80
70
60
50
40
30
20
10
0
0.01
0.1
1
10
450
0
5
10 15 20 25 30 35 40
VIN (V)
200
1 1.5
2 2.5
3 3.5
4 4.5
5
500
500
400
300
550
800
700
600
Case Temperature Rise vs.
Output Current
40
35
30
25
20
15
10
5
0
0
1
2
3
4
5
-1.00
-1.50
0.50
0.00
-0.50
1.50
1.00
Line Regulation
Load Regulation
1.00
0.50
0.00
-0.50
0
10
20
30
40
-1.00
0
1
2
3
4
5
MP9447 Rev. 1.2
1/5/2016
www.MonolithicPower.com
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
© 2016 MPS. All Rights Reserved.
5
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