MP1517
3A, 25V, 1.1MHz
Step-Up Converter
The Future of Analog IC Technology
DESCRIPTION
The MP1517 is a 3A, fixed frequency step-up
converter ideal for medium-to-high current
step-up, flyback and SEPIC applications. The
high 1.1MHz switching frequency allows for
smaller external components producing a
compact solution for size constrained cameras,
PDAs and cell phones. The low 0.7V feedback
voltage offers higher efficiency in white LED
driver applications including cell phone camera
flash. The MP1517 regulates the output voltage
up to 25V with efficiencies as high as 95%.
Soft-start, cycle-by-cycle current limiting, and
input
under
voltage
lockout
prevent
overstressing or damage to sensitive external
circuitry at startup and output short-circuit
conditions. Current-mode regulation and
external compensation components allow the
MP1517 control loop to be optimized over a
wide variety of input voltage, output voltage,
and load current conditions. The MP1517 is
available in the thermally enhanced QFN16
(4mm x 4mm) package.
FEATURES
•
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•
•
•
•
•
•
•
•
•
•
•
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4A Peak Current Limit
Low 700mV Feedback Threshold
Internal 150mΩ Power Switch
Input Range of 2.6V to 25V
Up to 95% Efficiency
Zero Current Shutdown Mode
Under Voltage Lockout Protection
Open Load Protection
Soft-Start Operation
Thermal Shutdown
Tiny 4mm x 4mm 16-Pin QFN Package
Boost and SEPIC Regulators
Handheld Computers
Cell Phone Camera Flash, PDAs
Digital Still and Video Cameras
APPLICATIONS
“MPS” and “The Future of Analog IC Technology” are Registered Trademarks of
Monolithic Power Systems, Inc.
EVALUATION BOARD REFERENCE
Board Number
EV0043
Dimensions
2.5”X x 2.0”Y x 0.4”Z
TYPICAL APPLICATION
V
IN
5V
Efficiency vs
Load Current
100
8
IN
4
15
9, 10
D1
MBR320
95
EFFICIENCY (%)
V
OUT
12V
OFF ON
EN
SS
SW
90
85
80
75
70
65
60
55
50
1
V
OUT
= 12V
C4
10nF
C5
10nF
3
7
MP1517
BP
OLS
SGND
5, 13
FB
16
1
COMP
PGND
11, 12
V
OUT
= 18V
V
IN
= 5V
10
100
LOAD CURRENT (mA)
1000
MP1517-EC01
C3
10nF
C6
OPTIONAL
MP1517_TAC_S01
MP1517 Rev. 1.4
9/21/2007
www.MonolithicPower.com
MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited.
© 2007 MPS. All Rights Reserved.
1
MP1517 – 3A, 25V, 1.1MHz STEP-UP CONVERTER
PACKAGE REFERENCE
TOP VIEW
PIN 1
IDENTIFICATION
FB
16
1
2
3
4
5
SGND
6
NC
7
OLS
8
IN
MP1517_PD01-QFN16
ABSOLUTE MAXIMUM RATINGS
(1)
EXPOSED PAD
CONNECT TO PIN 13
SS
15
NC
14
SGND
13
12
11
10
9
COMP
NC
BP
EN
PGND
PGND
SW
SW
Input Supply Voltage V
IN
.............. –0.3V to +27V
SW Pin Voltage V
SW
.................... –0.3V to +27V
Voltage at All Other
Pins except OLS .................................–0.3V to +6V
Storage Temperature ..............–65°C to +150°C
Junction Temperature.............................+150°C
Recommended Operating Conditions
(2)
IN Input Supply Voltage V
IN
............. 2.6V to 25V
Output Voltage................................. 3.3V to 25V
Operating Temperature .............–40°C to +85°C
Thermal Resistance
(3)
Part Number*
MP1517DR
*
Package
QFN16
(4mm x 4mm)
Temperature
–40°C to +85°C
QFN16 (4mm x 4mm) ............. 46 ...... 10...
°C/W
Notes:
1) Exceeding these ratings may damage the device.
2) The device is not guaranteed to function outside of its
operating conditions.
3) Measured on approximately 1” square of 1 oz. Copper.
θ
JA
θ
JC
For Tape & Reel, add suffix –Z (eg. MP1517DR–Z)
For Lead Free, add suffix –LF (eg. MP1517DR–LF–Z)
ELECTRICAL CHARACTERISTICS
V
IN
= 5.0V, T
A
= +25°C, unless otherwise noted.
Parameter
IN Shutdown Supply Current
IN Operating Supply Current
BP Voltage
IN Undervoltage Lockout
Threshold
IN Undervoltage Lockout
Hysteresis
EN Input Low Voltage
EN Input High Voltage
EN Input Hysteresis
EN Input Bias Current
SW Switching Frequency
SW Maximum Duty Cycle
Error Amplifier Voltage Gain
(4)
Error Amplifier Transconductance
COMP Maximum Output Current
FB Regulation Threshold
FB Input Bias Current
SS Charging Current
Symbol Condition
V
EN
≤
0.3V
V
EN
> 2V, V
FB
= 0.8V
V
IN
= 2.6V to 25V
V
IN
Rising
2.10
100
0.4
1.5
100
f
SW
V
FB
= 0.6V
A
VEA
G
EA
Sourcing and Sinking
679
V
FB
= 0.7V
During Soft-Start
0.9
85
1.1
93
400
350
30
700
2
1
1.3
Min
Typ
0.5
0.9
2.4
Max
1.0
1.2
2.40
Units
µA
mA
V
V
mV
V
V
mV
µA
MHz
%
V/V
µA/V
µA
mV
µA
µA
721
1
MP1517 Rev. 1.4
9/21/2007
www.MonolithicPower.com
MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited.
© 2007 MPS. All Rights Reserved.
2
MP1517 – 3A, 25V, 1.1MHz STEP-UP CONVERTER
ELECTRICAL CHARACTERISTICS
(continued)
V
IN
= 5.0V, T
A
= +25°C, unless otherwise noted.
Parameter
SW On Resistance
(4)
SW Current Limit
(4)
SW Leakage Current
Thermal Shutdown
(4)
Open Load Shutdown Threshold
Note:
4) Guaranteed by design.
Symbol Condition
V
IN
= 5V
V
IN
= 3V
V
SW
= 25V
Measured at OLS Pin
Min
3.0
Typ
150
225
4.0
0.5
160
27
Max
Units
mΩ
mΩ
A
µA
°C
V
TYPICAL PERFORMANCE CHARACTERISTICS
Efficiency vs
Load Current
100
FEEDBACK VOLTAGE (mV)
95
90
EFFICIENCY (%)
85
80
75
70
65
60
55
50
1
V
IN
= 12V
10
100
1000
LOAD CURRENT (mA)
10000
MP1517-EC01
Feedback Voltage vs
Temperature
715
710
705
700
695
690
685
-50
50
100
0
TEMPERATURE (°C)
150
V
OUT
= 18V
V
OUT
= 22V
MP1517-TPC01
Frequency vs
Temperature
1.15
91.8
91.7
FREQUENCY (MHz)
DUTY CYCLE (%)
1.10
91.6
91.5
91.4
91.3
91.2
1.00
-50
0
50
100
TEMPERATURE (°C)
150
Maximum Duty Cycle vs
Temperature
1.05
91.1
-50
0
50
100
TEMPERATURE (°C)
150
MP1517-TPC02
MP1517-TPC03
MP1517 Rev. 1.4
9/21/2007
www.MonolithicPower.com
MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited.
© 2007 MPS. All Rights Reserved.
3
MP1517 – 3A, 25V, 1.1MHz STEP-UP CONVERTER
TYPICAL PERFORMANCE CHARACTERISTICS
(continued)
Operating Supply
Current vs Temperature
940
920
900
880
860
840
820
-50
0
50
100
TEMPERATURE (°C)
150
2.43
2.42
BP Voltage vs
Temperature
4.8
4.6
4.4
4.2
4.0
3.8
3.6
3.4
3.2
0
50
100
TEMPERATURE (°C)
150
Current Limit vs
Temperature
BP VOLTAGE (V)
2.41
2.40
2.39
2.38
2.37
2.36
-50
CURRENT LIMIT (A)
3.0
-50
0
50
100
TEMPERATURE (°C)
150
MP1517-TPC04
MP1517-TPC05
MP1517-TPC06
PIN FUNCTIONS
Pin #
1
2, 6, 14
3
4
5, 13
7
Name
COMP
NC
BP
EN
SGND
OLS
Description
Compensation: Error Amplifier Output. Connect to a series RC network to compensate
the regulator control loop.
No Connect
Output of the Internal 2.4V Low Dropout Regulator. Connect a 10nF bypass capacitor
between BP and SGND. Do not apply an external load to BP.
Regulator On/Off Control Input. A logic high input (V
EN
> 1.5V) turns on the regulator, a
logic low puts it into low current shutdown mode.
The EN pin cannot be left floating.
Signal Ground
Open Load Shutdown Pin. OLS senses regulator output voltage to protect IC during
open load operation. When this pin’s voltage exceeds 27V, the output switch is shut off.
The device then restarts in soft-start mode until it is disabled.
Input Supply Pin. This pin can be connected to the regulator’s input supply or to the
output for boot-strapped operation.
Output Switch Node. SW is the drain of the internal N-Channel MOSFET. Connect the
inductor and rectifier to SW to complete the step-up converter.
Power Ground
Soft-Start Input. Connect a 10nF to 22nF capacitor from SS to SGND to set the soft-start
time. SS sources 2µA to an external soft-start capacitor during startup. As the voltage at
SS increases to 0.55V, the voltage at COMP is clamped to 0.7V above the voltage at SS
limiting the startup current. The external capacitor at SS is discharged to ground when
under voltage lockout, thermal shutdown occurs or open load shutdown occurs.
Regulation Feedback Input. The regulation threshold is 0.7V.
8
9, 10
11, 12
IN
SW
PGND
15
SS
16
FB
MP1517 Rev. 1.4
9/21/2007
www.MonolithicPower.com
MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited.
© 2007 MPS. All Rights Reserved.
4
MP1517 – 3A, 25V, 1.1MHz STEP-UP CONVERTER
OPERATION
The MP1517 uses a 1.1MHz fixed-frequency,
current-mode regulation architecture to regulate
the output. The operation of the MP1517 can be
understood by referring to the block diagram of
Figure 1. At the beginning of each cycle, the
N-Channel MOSFET switch is turned on,
forcing the inductor current to rise. The current
at the source of the switch is internally
measured and converted to a voltage by the
current sense amplifier. That voltage is
compared to the error voltage at COMP. The
voltage at the output of the error amplifier is an
amplified version of the difference between the
IN
8
BP
EN
OLS
3
4
7
16V
9, 10 SW
PWM
CONTROL
LOGIC
OSCILLATOR
2.4V
LDO
700mV reference voltage and the feedback
voltage. When these two voltages are equal,
the PWM comparator turns off the switch
forcing the inductor current to the output
capacitor through the external rectifier. This
causes the inductor current to decrease. The
peak inductor current is controlled by the
voltage at COMP, which in turn is controlled by
the output voltage. Thus the output voltage
controls the inductor current to satisfy the load.
The use of current-mode regulation improves
transient response and control loop stability.
+
0.9V
--
+
2.4V
--
CURRENT
SENSE
AMP
+
--
SS 15
--
SOFT-START
GM
+
0.7V
11, 12 PGND
16 FB
1
COMP
5, 13
SGND
MP1517_BD01
Figure 1—Functional Block Diagram
MP1517 Rev. 1.4
9/21/2007
www.MonolithicPower.com
MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited.
© 2007 MPS. All Rights Reserved.
5
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