MP2012
Low Voltage, 2.7-6V Input,1.5A, 1.2MHz
Synchronous Step-Down Converter
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The Future of Analog IC Technology
DESCRIPTION
FEATURES
The MP2012 is a fully integrated, internally
compensated 1.2MHz fixed frequency PWM
step-down converter. It is ideal for powering
portable equipment that runs from a single cell
Lithium-Ion (Li+) Battery, with an input range
from 2.7V to 6V. The MP2012 can provide up to
1.5A of load current with output voltage as low
as 0.8V. It can also operate at 100% duty cycle
for low dropout applications. With peak current
mode control and internal compensation, the
MP2012 is stable with ceramic capacitors and
small inductors. Fault condition protection
includes cycle-by-cycle current limiting and
thermal shutdown.
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MP2012 is available in a small QFN6 (3x3mm)
package.
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2.7-6V Input Operation Range
Output Adjustable from 0.8V to VIN
1μA Max Shutdown Current.
Up to 95% Efficiency
100% Duty Cycle for Low Dropout
Applications
1.2MHz Fixed Switching Frequency
Stable with Low ESR Output Ceramic
Capacitors
Thermal Shutdown
Cycle-by-Cycle Over Current Protection
Short Circuit Protection
Available in QFN6 (3x3mm)
APPLICATIONS
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DVD+/-RW Drives
Smart Phones
PDAs
Digital Cameras
Portable Instruments
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“MPS” and “The Future of Analog IC Technology” are Trademarks of Monolithic
Power Systems, Inc.
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VIN
2.7V to 6V
Efficiency vs.
Load Current
100
4
5
C1
PVIN
VIN
EN
MP2012
SW
EN
6
3
90
VOUT
1.8V/1.5A
L1
R1
2
GND
FB 1
Rt
C2
R2
80
EFFICIENCY (%)
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TYPICAL APPLICATION
Vin=5V
70
Vin=3V
60
50
40
30
20
10
0
0
0.3
0.6
0.9
1.2
1.5
LOAD CURRENT(A)
MP2012 Rev. 1.01
9/22/2011
www.MonolithicPower.com
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
© 2011 MPS. All Rights Reserved.
1
MP2012 – 1.5A SYNCHRONOUS STEP-DOWN CONVERTER
ORDERING INFORMATION
Package
Top Marking
Free Air Temperature (TA)
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Part Number*
MP2012DQ
QFN6(3x3mm)
9E
–40°C to +85°C
* For Tape & Reel, add suffix –Z (e.g. MP2012DQ–Z).
For RoHS compliant packaging, add suffix –LF (e.g. MP2012DQ–LF–Z)
PACKAGE REFERENCE
TOP VIEW
FB
1
6
EN
GND
2
5
VIN
SW
3
4
PVIN
Exposed Pad
Connected to GND
Thermal Resistance
PVIN, VIN to GND......................–0.3V to + 6.5V
SW to GND .......................... –0.3V to VIN + 0.3V
EN, FB to GND ...........................–0.3V to +6.5V
Operating Temperature............. –40°C to +85°C
(2)
Continuous Power Dissipation (TA = +25°C)
………………………………………………....2.5W
Junction Temperature ...............................150°C
Lead Temperature ....................................260°C
Storage Temperature ............. –65°C to +150°C
QFN6 (3x3mm) .......................50 ...... 12 ... °C/W
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ABSOLUTE MAXIMUM RATINGS (1)
Recommended Operating Conditions
(3)
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Supply Voltage VIN .............................2.7V to 6V
Operating Junct. Temp (TJ)..... –40°C to +125°C
MP2012 Rev. 1.01
9/22/2011
(4)
θJA
θJC
Notes:
1) Exceeding these ratings may damage the device.
2) The maximum allowable power dissipation is a function of the
maximum junction temperature TJ (MAX), the junction-toambient thermal resistance θJA, and the ambient temperature
TA. The maximum allowable continuous power dissipation at
any ambient temperature is calculated by PD (MAX) = (TJ
(MAX)-TA)/θJA. 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.
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© 2011 MPS. All Rights Reserved.
2
MP2012 – 1.5A SYNCHRONOUS STEP-DOWN CONVERTER
ELECTRICAL CHARACTERISTICS (5)
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VIN = VEN = 3.6V, TA = +25°C, unless otherwise noted.
Parameters
Condition
Supply Current
VEN_= VIN, VFB = 0.9V
Shutdown Current
Thermal Shutdown Trip Threshold
EN Trip Threshold
EN Input Current
EN Input Current
IN Undervoltage Lockout Threshold
IN Undervoltage Lockout Hysteresis
VEN_= 0V, VIN = 6V
Hysteresis = 20°C
-40°C ≤ TA ≤ +85°C
VEN = 0V
VEN = 6V
Rising Edge
Regulated FB Voltage
FB Input Bias Current
SW PFET On Resistance
SW NFET On Resistance
SW Leakage Current
SW Leakage Current
SW PFET Peak Current Limit
Switching Frequency
TA = +25°C
-40°C≤ TA≤ +85°C
VFB = 0.8V
ISW = 100mA
ISW = -100mA
VEN=0V; VIN=6V
VSW_=0V
VEN=0V; VIN=6V
VSW_=6V
Duty Cycle=100%
Duty Cycle=50%(6)
Min
Typ
Max
Units
600
750
μA
1
μA
°C
V
μA
μA
V
mV
0.784
0.776
-50
0.18
0.14
0.01
150
1.0
0.1
6
2.40
160
0.800
0.800
-2
0.25
0.2
0.816
0.824
+50
0.28
0.24
nA
Ω
Ω
-1
0.1
1
μA
-5
1.5
5
μA
0.3
2.15
2.1
1.0
3.0
3.5
1.2
1.5
1.0
2.65
V
A
1.4
MHz
Notes:
5) Production test at +25°C. Specifications over the temperature range are guaranteed by design and characterization.
PIN FUNCTIONS
Pin #
Feedback input. An external resistor divider from the output to GND, tapped to the FB
pin sets the output voltage.
GND,
Exposed Pad
Ground pin. Connect exposed pad to ground plane for proper thermal
performance.
SW
PVIN
VIN
EN
Switch node to the inductor.
Input supply pin for power FET.
Input Supply pin for controller. Put small decoupling ceramic near this pin.
Enable input, “High” enables MP2012. EN is pulled to GND with 1Meg internal resistor.
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5
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Description
FB
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1
Name
MP2012 Rev. 1.01
9/22/2011
www.MonolithicPower.com
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
© 2011 MPS. All Rights Reserved.
3
MP2012 – 1.5A SYNCHRONOUS STEP-DOWN CONVERTER
TYPICAL PERFORMANCE CHARACTERISTICS
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VIN = 5V, VOUT = 1.8V, L=3.3uH, TA = +25ºC, unless otherwise noted.
100
90
Vin=5V
70
Vin=3V
60
50
40
30
20
10
0
0
0.3
0.6
0.9
1.2
850
35
800
30
750
25
700
20
650
15
600
10
550
5
500
2.5
1.5
3
3.5
LOAD CURRENT(A)
Load Regulation
5.5
0
0
6
Vin=3V
-0.1%
-0.2%
4.5
4
0.20%
Io=0A
0.00%
Io=0.75A
-0.20%
Vin=5V
Io=1.5A
-0.40%
-0.3%
0
0.5
1
-0.60%
3.5
3
2.5
2
2 2.5
3 3.5
4 4.5
5 5.5
INPUT VOLTAGE (V)
6
1.5
40% 50% 60% 70% 80% 90% 100%
DUTY CYCLE
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LOAD CURRENT(A)
1.5
0.5
1
1.5
OUTPUT CURRENT (A)
Peak Current vs. Duty
0.40%
0.0%
-0.4%
5
Line Regulation
LINE REGULATION
LOAD REGULATION
0.1%
4 4.5
V IN(V)
PEAK CURRENT(A)
EFFICIENCY (%)
80
Case Tem perature Risevs.
Output Current
Enable Supply Current vs.
Input Voltage
Efficiency vs.
Load Current
MP2012 Rev. 1.01
9/22/2011
www.MonolithicPower.com
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
© 2011 MPS. All Rights Reserved.
4
MP2012 – 1.5A SYNCHRONOUS STEP-DOWN CONVERTER
TYPICAL PERFORMANCE CHARACTERISTICS
VOUT
2V/div
SW
2V/div
VIN
10V/div
IINDUCTOR
2A/div
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VIN = 5V, VOUT = 1.8V, L=3.3uH, TA = +25ºC, unless otherwise noted.
Short Entry
Short Recovery
Full Load
No Load
VOUT
1V/div
VOUT
1V/div
SW
5V/div
SW
5V/div
VIN
10V/div
VIN
5V/div
IINDUCTOR
2A/div
IINDUCTOR
1A/div
Power Up with 1.5A Load
VOUT
1V/div
SW
5V/div
VIN
5V/div
VOUT
1V/div
VOUT
1V/div
SW
5V/div
SW
5V/div
EN
2V/div
EN
2V/div
IINDUCTOR
1A/div
IINDUCTOR
1A/div
VOUT
20mV/div
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SW
2V/div
VOUT
20mV/div
SW
2V/div
IINDUCTOR
2A/div
400ns/div
MP2012 Rev. 1.01
9/22/2011
Load Transient Response
IOUT=0.75A-1.5A Step @ 1A/us
Output Ripple Voltage
Input Ripple Voltage
VIN
50mV/div
EN Start up with 1.5A Load
EN Start Up without Load
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IINDUCTOR
1A/div
Power Up without Load
IOUT
500mA/div
400ns/div
400us/div
www.MonolithicPower.com
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
© 2011 MPS. All Rights Reserved.
5
MP2012 – 1.5A SYNCHRONOUS STEP-DOWN CONVERTER
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FUNCTION BLOCK DIAGRAM
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Figure 1―Function Block Diagram
MP2012 Rev. 1.01
9/22/2011
www.MonolithicPower.com
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
© 2011 MPS. All Rights Reserved.
6
MP2012 – 1.5A SYNCHRONOUS STEP-DOWN CONVERTER
OPERATION
The steady state duty cycle D for this mode can
be calculated as:
D = TON × fOSC × 100% ≈
VOUT
× 100%
VIN
Where TON is the main switch on time and fOSC is
the oscillator frequency (1.2MHz typ.).
Current Mode PWM Control
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Slope compensated current mode PWM control
provides stable switching and cycle-by-cycle
current limiting for superior load and line
response as well as protection of the internal
main switch and synchronous rectifier. The
MP2012 switches at a constant frequency
(1.2MHz) and modulates the inductor peak
current to regulate the output voltage. Specifically,
for each cycle the PWM controller forces the
inductor peak current to an internal reference
level derived from the feedback error voltage. At
normal operation, the main switch is turned on at
each rise edge of the internal oscillator, and
remains on for a certain period of time to ramp up
the inductor current. As soon as the inductor
current reaches the reference level, the main
switch is turned off and immediately the
synchronous rectifier will be turned on to provide
the inductor current. In forced PWM mode, the
synchronous rectifier will stay on until the next
oscillator cycle.
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Dropout Operation
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The MP2012 is a fixed frequency 1.2MHz current
mode 1.5A step-down converter, optimized for
low voltage, Li-Ion battery powered applications
where high efficiency and small size are critical.
MP2012 integrates a high side PFET main switch
and a low side synchronous rectifier. It always
operates in continuous conduction mode,
simplifies the control scheme and eliminates the
random spectrum noise due to discontinuous
conduction mode.
MP2012 Rev. 1.01
9/22/2011
The MP2012 allows the main switch to remain on
for more than one switching cycle to increase the
duty cycle when the input voltage is dropping
close to the output voltage. When the duty cycle
reaches 100%, the main switch is held on
continuously to deliver current to the output up to
the PFET current limit. In this case, the output
voltage becomes the input voltage minus the
voltage drop across the main switch and the
inductor.
Maximum Load Current
The MP2012 can operate down to 2.5V input
voltage; however the maximum load current
decreases at lower input due to a large IR drop
on the main switch and synchronous rectifier.
The slope compensation signal reduces the peak
inductor current as a function of the duty cycle to
prevent sub-harmonic oscillations at duty cycles
greater than 50%. Conversely, the current limit
increases as the duty cycle decreases.
Short Circuit Protection
When short circuit or over current condition
happens, and FB is lower than about 0.3V, the
MP2012 enters fold back mode. The oscillator
frequency is reduced to prevent the inductor
current from increasing beyond the PFET current
limit. The PFET current limit is also reduced to
lower the short circuit current. The frequency and
current limit will return to the normal values once
the short circuit condition is removed and the
feedback voltage approaches 0.8V.
www.MonolithicPower.com
MPS Proprietary Information. Patent Protected. Unauthorized Photocopy and Duplication Prohibited.
© 2011 MPS. All Rights Reserved.
7
MP2012 – 1.5A SYNCHRONOUS STEP-DOWN CONVERTER
APPLICATION INFORMATION
R R
1
8
.
0
⎞
⎟
⎠
2
Cooper
VOUT
R1
Rt
FB
R2
Figure 2―Feedback Network
Table 1 lists the recommended resistor value for
common output voltages.
Table 1—Resistor Selection vs. Output
Voltage Setting
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VOUT × (VIN − VOUT )
VIN × ΔIL × fOSC
Where ΔIL is inductor ripple current. Choose
inductor ripple current approximately 30% of the
maximum load current, 1.5A.
The maximum inductor peak current is:
IL(MAX ) = ILOAD
MP2012 Rev. 1.01
9/22/2011
ΔI
+ L
2
=
)⎛
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L=
−
1 C
Inductor Selection
A 1μH to 10μH inductor with DC current rating at
least 25% higher than the maximum load current
is recommended for most applications. For best
efficiency, the inductor DC resistance shall be
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