MP28313
2A, 16V, 340KHz Synchronous Rectified
Step-Down Converter
The Future of Analog IC Technology
DESCRIPTION
The MP28313 is a monolithic synchronous buck
regulator. The device integrates 130mΩ
MOSFETS that provide 2A continuous load
current over a wide operating input voltage of
5V to 16V. Current mode control provides fast
transient response and cycle-by-cycle current
limit.
An adjustable soft-start prevents inrush current
at turn-on. Shutdown mode drops the supply
current to 1µA.
This device, available in an 8-pin SOIC
package, provides a very compact system
solution with minimal reliance on external
components.
FEATURES
•
•
•
•
•
•
•
•
•
•
•
•
•
•
•
2A Output Current
Wide 5V to 16V Operating Input Range
Integrated 130mΩ Power MOSFET Switches
Output Adjustable from 0.923V to 13V
Up to 93% Efficiency
Programmable Soft-Start
Stable with Low ESR Ceramic Output Capacitors
Fixed 340KHz Frequency
Cycle-by-Cycle Over Current Protection
Input Under Voltage Lockout
Distributed Power Systems
Networking Systems
FPGA, DSP, ASIC Power Supplies
Green Electronics/ Appliances
Notebook Computers
APPLICATIONS
“MPS” and “The Future of Analog IC Technology” are Registered Trademarks of
Monolithic Power Systems, Inc.
TYPICAL APPLICATION
INPUT
5V to 16V
C5
10nF
Efficiency vs
Load Current
100
95
V
OUT
= 3.3V
V
OUT
= 2.5V
90
EFFICIENCY (%)
2
7
IN
EN
1
BS
3
SW
MP28313
8
SS
GND
4
FB
COMP
6
5
OUTPUT
3.3V
2A
85
80
75
70
65
60
55
50
0
C3
3.3nF
0.5
1.0
1.5
2.0
LOAD CURRENT (A)
2.5
MP28313_EC01
MP28313 Rev. 1.5
9/27/2010
www.MonolithicPower.com
MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited.
© 2010 MPS. All Rights Reserved.
1
MP28313 – 2A, 16V, 340KHz SYNCHRONOUS RECTIFIED, STEP-DOWN CONVERTER
ORDERING INFORMATION
Part Number
MP28313CS*
MP28313DS
Package
SOIC8
Top Marking
MP28313CS
MP28313DS
Free Air Temperature (T
A
)
0°C to +85°C
–40°C to +85°C
* For Tape & Reel, add suffix –Z (e.g. MP28313CS–Z)
For RoHS compliant packaging, add suffix –LF (e.g. MP28313CS–LF–Z)
PACKAGE REFERENCE
TOP VIEW
BS
IN
SW
GND
1
2
3
4
8
7
6
5
SS
EN
COMP
FB
MP28313_PD01
ABSOLUTE MAXIMUM RATINGS
(1)
Supply Voltage V
IN
.......................–0.3V to +22V
Switch Voltage V
SW
.................. –1V to V
IN
+0.3V
Boost Voltage V
BS
..........V
SW
– 0.3V to V
SW
+ 6V
All Other Pins .................................–0.3V to +6V
Continuous Power Dissipation
(T
A
= +25°C)
(2)
…………………………………………………1.4W
Junction Temperature ...............................150°C
Lead Temperature ....................................260°C
Storage Temperature ............. –65°C to +150°C
Thermal Resistance
(4)
SOIC8 .....................................90 ...... 45 ...
°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.
.
θ
JA
θ
JC
Recommended Operating Conditions
(3)
Input Voltage V
IN
.................................5V to 16V
Output Voltage V
OUT
.....................0.923V to 13V
MP28313CS Operating Junct. Temp (T
J
).............
……………………………………….0°C to +85°C
MP28313DS Operating Junct. Temp (T
J
).............
……………………………………...-40°C to +85°C
MP28313 Rev. 1.5
9/27/2010
www.MonolithicPower.com
MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited.
© 2010 MPS. All Rights Reserved.
2
MP28313 – 2A, 16V, 340KHz SYNCHRONOUS RECTIFIED, STEP-DOWN CONVERTER
ELECTRICAL CHARACTERISTICS
V
IN
= 12V, T
A
= +25°C, unless otherwise noted.
Parameter
Shutdown Supply Current
Supply Current
Feedback Voltage
Feedback Overvoltage
Threshold
Error Amplifier Voltage Gain
(5)
High-Side Switch On Resistance
(5)
Symbol Condition
V
EN
= 0V
V
EN
= 2.0V; V
FB
= 1.0V
V
FB
5V
≤
V
IN
≤
16V, T
A
=+25°C
T
A
= 0°C to +85°C
T
A
= -40°C to +85°C
Min
Typ
1
1.3
Max
10
1.8
0.937
.941
.941
Units
µA
mA
V
V
V
V/V
mΩ
mΩ
0.909
.906
.905
0.923
1.1
A
EA
R
DS(ON)1
R
DS(ON)2
V
EN
= 0V, V
SW
= 0V
Minimum Duty Cycle
F
osc1
F
osc2
D
MAX
V
FB
= 0V
V
FB
= 1.0V
V
EN
Rising
87
1.1
2.6
300
3.4
340
100
90
220
1.5
210
2.2
V
IN
Rising
3.80
2.5
210
4.10
210
V
SS
= 0V
C
SS
= 0.1µF
145
6
15
160
2.7
4.40
340
2.0
400
130
130
10
Low-Side Switch On Resistance
(5)
High-Side Switch Leakage
Current
Upper Switch Current Limit
Oscillation Frequency
Short Circuit Oscillation
Frequency
Maximum Duty Cycle
Minimum On Time
(5)
EN Shutdown Threshold Voltage
EN Shutdown Threshold Voltage
Hysteresis
EN Lockout Threshold Voltage
EN Lockout Hysterisis
Input Under Voltage Lockout
Threshold
Input Under Voltage Lockout
Threshold Hysteresis
Soft-Start Current
Soft-Start Period
Thermal Shutdown
(5)
Note:
5) Guaranteed by design, not tested.
µA
A
KHz
KHz
%
ns
V
mV
V
mV
V
mV
µA
ms
°C
MP28313 Rev. 1.5
9/27/2010
www.MonolithicPower.com
MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited.
© 2010 MPS. All Rights Reserved.
3
MP28313 – 2A, 16V, 340KHz SYNCHRONOUS RECTIFIED, STEP-DOWN CONVERTER
PIN FUNCTIONS
Pin #
1
2
Name
BS
IN
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 5V to 16V power source. Bypass IN to GND with a suitably large capacitor to
eliminate noise on the input to the IC. See
Input Capacitor.
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.
Feedback Input. FB senses the output voltage to regulate that voltage. Drive FB with a
resistive voltage divider from the output voltage. The feedback threshold is 0.923V. See
Setting the Output Voltage.
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. See
Compensation
Components.
Enable Input. EN is a digital input that turns the regulator on or off. Drive EN high to turn on
the regulator, drive it low to turn it off. Pull up with 100kΩ resistor for automatic startup.
Soft-Start Control Input. SS controls the soft start period. Connect a capacitor from SS to GND
to set the soft-start period. A 0.1µF capacitor sets the soft-start period to 15ms. To disable the
soft-start feature, leave SS unconnected.
3
4
5
SW
GND
FB
6
COMP
7
8
EN
SS
MP28313 Rev. 1.5
9/27/2010
www.MonolithicPower.com
MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited.
© 2010 MPS. All Rights Reserved.
4
MP28313 – 2A, 16V, 340KHz SYNCHRONOUS RECTIFIED, STEP-DOWN CONVERTER
TYPICAL PERFORMANCE CHARACTERISTICS
V
IN
= 12V, V
O
= 3.3V, L = 10µH, C1 = 10µF, C2 = 22µF, T
A
= +25°C, unless otherwise noted.
Steady State Test
V
IN
= 12V, V
OUT
= 3.3V
I
OUT
= 0A, I
IN
= 8.2mA
V
IN
20mV/div.
V
OUT
20mV/div.
I
L
1A/div.
V
EN
5V/div.
V
OUT
2V/div.
I
L
1A/div.
V
SW
10V/div.
Startup through Enable
V
IN
= 12V, V
OUT
= 3.3V
I
OUT
= 1A (Resistance Load)
V
EN
5V/div.
V
OUT
2V/div.
I
L
1A/div.
V
SW
10V/div.
Shutdown through Enable
V
IN
= 12V, V
OUT
= 3.3V
I
OUT
= 1A (Resistance Load)
V
SW
10V/div.
MP28313-TPC01
2ms/div.
MP28313-TPC02
2ms/div.
MP28313-TPC03
Heavy Load Operation
2A Load
V
IN, AC
200mV/div.
V
O, AC
20mV/div.
I
L
1A/div.
V
SW
10V/div.
V
IN, AC
200mV/div.
V
O, AC
20mV/div.
I
L
1A/div.
Medium Load Operation
1A Load
V
IN, AC
20mV/div.
Light Load Operation
No Load
V
O, AC
20mV/div.
I
L
1A/div.
V
SW
10V/div.
V
SW
10V/div.
MP28313-TPC04
MP28313-TPC05
MP28313-TPC06
Short Circuit
Protection
Short Circuit
Recovery
Load Transient
V
OUT
2V/div.
V
OUT
2V/div.
V
OUT
200mV/div.
I
L
2A/div.
I
L
1A/div.
I
L
2A/div.
I
LOAD
1A/div.
MP28313-TPC07
MP28313-TPC08
MP28313-TPC09
MP28313 Rev. 1.5
9/27/2010
www.MonolithicPower.com
MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited.
© 2010 MPS. All Rights Reserved.
5
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