MP2115
2A Synchronous Step-Down Converter
with Programmable Input Current Limit
The Future of Analog IC Technology
DESCRIPTION
The MP2115 is a high frequency, current mode,
PWM step-down converter with integrated input
current limit switch. The step-down converter
integrates a main switch and a synchronous
rectifier for high efficiency without an external
Schottky diode. The input average current limit
can be externally programmed. It is ideal for
powering portable equipment that is powered
by an USB port. The MP2115 can supply 2A of
load current from a 2.8V to 6V input voltage.
The output voltage can be regulated as low as
0.6V.
The MP2115 is available in a space-saving
10-pin QFN package.
FEATURES
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High Efficiency: Up to 92%
Programmable Switching Frequency from
0.7MHz-2MHz
Programmable Input Current Limit
2A Available Load Current
2.8V to 6V Input Voltage Range
Output Voltage as Low as 0.6V
Current Mode Control
Power Good Indicator
Short Circuit Protection
Thermal Fault Protection
<0.1µA Shutdown Current
Space Saving 3mm x 3mm QFN10 Package
USB Powered Devices
Cellular and Smart Phones
Microprocessors and DSP Core Supplies
PDAs
MP3 Players
Digital Still and Video Cameras
Portable Instruments
APPLICATIONS
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“MPS” and “The Future of Analog IC Technology” are Registered Trademarks of
Monolithic Power Systems, Inc.
TYPICAL APPLICATION
VIN
USB Input
R4
100k
R3
100k
U1
PG
EN
Efficiency
100
90
V
IN
=5.0V
V
OUT
=3.8V, Freq=1.5MHz
1
VSYS
8
10
PG
EN
SW
FB
7
3
R1
51k
3.8V/2A
C5
220pF
VOUT
EFFICIENCY (%)
VIN
VSYS
9
V
IN
=5.5V
MP2115DQ
6 PGND
FREG
2 ILIM
80
70
60
50
0.0
4 AGND
6TPE470MI x 3
5
R6
86.6k
R5
24.9k
R2
9.53k
0.1
0.2
0.3
0.4
0.5
0.6
LOAD CURRENT ( A )
MP2115 Rev. 1.0
2/28/2011
www.MonolithicPower.com
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
© 2011 MPS. All Rights Reserved.
1
MP2115 – 2A, 6V SYNCHRONOUS STEP-DOWN CONVERTER
ORDERING INFORMATION
Part Number*
MP2115DQ
Package
QFN10 (3mm x 3mm)
Top Marking
2X
Free Air Temperature (T
A
)
-40°C to +85°C
* For Tape & Reel, add suffix –Z (e.g. MP2115DQ–Z).
For RoHS compliant packaging, add suffix –LF (e.g. MP2115DQ–LF–Z)
PACKAGE REFERENCE
TOP VIEW
VIN
ILIM
FB
GND
FREQ
1
2
3
4
5
10 PG
9
8
7
6
EN
VSYS
SW
PGND
EXPOSED PAD
ON BACKSIDE
CONNECT TO GND
ABSOLUTE MAXIMUM RATINGS
(1)
V
IN
to GND ...................................-0.3V to +6.5V
V
SW
to GND ............................ -0.3V to V
IN
+0.3V
V
FB
, V
EN
, PG, VSYS, ILIM to GND
...............................................-0.3V to +6.5V
Continuous Power Dissipation (T
A
= +25°C)
(2)
............................................................. 2.5W
Junction Temperature ............................ +150°C
Lead Temperature ................................. +260°C
Storage Temperature .............. -65°C to +150°C
Thermal Resistance
(4)
QFN10 (3x3) ........................... 50 ...... 12...
°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)
Supply Voltage V
IN
............................. 2.8V to 6V
Output Voltage V
OUT
........................... 0.6V to 6V
Maximum Junction Temp. (T
J
) ............... +125°C
MP2115 Rev. 1.0
2/28/2011
www.MonolithicPower.com
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
© 2011 MPS. All Rights Reserved.
2
MP2115 – 2A, 6V SYNCHRONOUS STEP-DOWN CONVERTER
ELECTRICAL CHARACTERISTICS
(5)
V
IN
= V
EN
= 5.0V, T
A
= +25°C, unless otherwise noted.
Parameter
Supply Current
Shutdown Current
IN Undervoltage Lockout Threshold
IN Undervoltage Lockout Hysteresis
Regulated FB Voltage
FB Input Bias Current
PFET On Resistance
NFET On Resistance
Load Switch PFET On Resistance
Load Switch Current Set
SW Leakage Current
PFET Current Limit
（
6
）
Oscillator Frequency
Thermal Shutdown Trip Threshold
EN Input Low Voltage
En Input High Voltage
EN Input Current
Power Good Ramp Up Threshold
Power Good Ramp Down Threshold
Soft Start Time
Power Good Sink Current Capability
Power Good Leakage Current
0.3
1.65
-1
f
OSC
R
FREQ
= 100kΩ
Symbol Condition
V
EN
= V
IN
, V
FB
= 0.65V
V
EN
= 0V, V
IN
= 6V
Rising Edge
T
A
= +25°C
-40°C
≤
T
A
≤
+85°C
V
FB
= 0.65V
I
SW
= 100mA
I
SW
= -100mA
R
ILIM
=25kΩ
V
EN
= 0V, V
IN
= 6V,
V
SW
= 0V or 6V
Min
Typ
800
0.10
2.35
60
0.607
0.607
0.5
0.1
0.1
0.22
500
-1
3.5
1.05
1.3
145
1.32
1.75
80
70
100
-50
0.5
50
1.45
2
1
1.55
+1
Max
1000
1
2.45
0.619
0.625
+50
Units
µA
µA
V
mV
V
nA
Ω
Ω
Ω
mA
µA
A
MHz
°C
V
V
µA
%
%
µs
V
nA
2.2
0.595
0.589
-50
V
FB
V
IN
= 0V to 6V
C5=220pF
V
PG
I
PG
LEAK
Sink 4mA
V
PG
= 3.3V
Note:
5) 100% production test at +25°C. Specifications over the temperature range are guaranteed by design and characterization.
6）Guaranteed by design
MP2115 Rev. 1.0
2/28/2011
www.MonolithicPower.com
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
© 2011 MPS. All Rights Reserved.
3
MP2115 – 2A, 6V SYNCHRONOUS STEP-DOWN CONVERTER
PIN FUNCTIONS
Pin #
1
2
3
4
5
6
7
8
9
10
Name
VIN
ILIM
FB
AGND
FREQ
Description
Supply Input for the power stage.
Input Current Limit setting pin. A resistor from this pin to ground sets the input current limit.
Feedback Input. Connect FB to the center point of the external resistor divider. The feedback
threshold voltage is 0.6V.
Analog Ground.
Switching Frequency Program Input. Connect a resistor from this pin to ground to set the
switching frequency.
PGND
Exposed The exposed pad and PGND pin must be connected to the same ground plane.
Pad
SW
Power Switch Output. Inductor connection to drains of the internal PFET and NFET switches.
Load switch output and switching regulator input. Usually this pin connects to a large tantalum
VSYS
capacitor as energy reservoir.
EN
On/Off Control Input.
Power good signal. When FB is less than 80% of 0.6V, PG is low. It is an open-drain output.
PG
Use a high value pull-up resistor externally to pull it up to system power supply.
MP2115 Rev. 1.0
2/28/2011
www.MonolithicPower.com
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
© 2011 MPS. All Rights Reserved.
4
MP2115 – 2A, 6V SYNCHRONOUS STEP-DOWN CONVERTER
TYPICAL PERFORMANCE CHARACTERISTICS
C1=10µF, C2=470µFx3, C4=220µF, C5=220pF, L= 4.7µH, T
A
= +25°C, unless otherwise noted.
Efficiency vs.
Load Current
100
90
80
70
60
50
0.0
V
OUT
= 3.8V, Freq=1.5MHz
V
IN
=5.0V
3.870
Load Regulation
50
40
30
20
3.866
3.864
3.862
3.860
0.0
10
0
-10
-20
-30
-40
-50
Loop Gain with Phase Margin
V
IN
= 5V, V
OUT
= 3.8V, I
OUT
= 0.5A
180
144
108
72
36
0
-36
-72
-108
-144
-180
1000
OUTPUT VOLTAGE (V)
EFFICIENCY (%)
V
IN
=5.5V
3.868
0.1
0.2
0.3
0.4
0.5
0.6
0.1
0.2
0.3
0.4
0.5
0.6
0.1
1
10
100
LOAD CURRENT (A)
LOAD CURRENT (A)
FREQUENCY (kHz)
I
LIMIT
Resistor vs.
Input Current
60
50
40
30
20
10
0
0.2
0.28
0.36
0.44
0.52
0.6
F
SW
vs. Resistor
SWITCHING FREQUENCY (MHz)
2.0
0.65
0.62
V
FB
vs. Temperature
V
IN
= 5V
70
V
IN
VOLTAGE(Y)
1.6
0.59
0.56
0.53
0.50
- 40 - 20
1.2
0.8
0.4
50 100 150 200 250 300 350 400
0
20
40
60
80 100
INPUT CURRENT (A)
Transient Response
V
IN
= 5V, V
OUT
= 3.8V,
I
OUT
= 0.7A/4.66ms
1.35
F
SW
vs. Temperature
V
IN
= 5V
SWITCHING FREQUENCY (MHz)
V
OUT
0.1V/div.
V
OUT
0.1V/div.
1.34
1.33
1.32
1.31
1.30
-40 -20
I
OUT
1A/div.
I
OUT
0.5A/div.
0
20
40
60
80 100
MP2115 Rev. 1.0
2/28/2011
www.MonolithicPower.com
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
© 2011 MPS. All Rights Reserved.
5
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