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MP4350DQ-LF-P

P1-P3P4-P6P7-P9P10-P12P13-P14
MP4350
2.5A, 4MHz, 20V
Step-Down Converter
MP4350 Rev. 1.0 www.MonolithicPower.com 1
5/26/2008 MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited.
© 2008 MPS. All Rights Reserved.
The Future of Analog IC Technology
DESCRIPTION
The MP4350 is a high frequency step-down
switching regulator with an integrated internal
high-side high voltage power MOSFET. It
provides 2.5A output with current mode control
for fast loop response and easy compensation.
The wide 4.5V to 20V input range
accommodates a variety of step-down
applications, including those in an automotive
input environment. A 100µA operational
quiescent current allows use in battery-powered
applications.
High power conversion efficiency over a wide
load range is achieved by scaling down the
switching frequency at light load condition to
reduce the switching and gate driving losses.
The frequency foldback helps prevent inductor
current runaway during startup and thermal
shutdown provides reliable, fault tolerant
operation.
By switching at 4MHz, the MP4350 is able to
prevent switching related EMI (Electromagnetic
Interference) noise problems, such as those
found in AM radio and ADSL applications.
The MP4350 is available in a small 3mm x 3mm
10-pin QFN package.
FEATURES
• 100µA Quiescent Current
• Wide 4.5V to 20V Operating Input Range
• 150m Internal Power MOSFET
• Up to 4MHz Programmable Switching
Frequency
• Ceramic Capacitor Stable
• Internal Soft-Start
• Internal Set Current Limit without a Current
Sensing Resistor
• Up to 95% Efficiency
• Output Adjustable from 0.8V to 16V
• Available in a 10-Pin QFN (3mm x 3mm) Package
APPLICATIONS
• DSL Power
• Set Top Boxes
• Battery Powered Systems
“MPS” and “The Future of Analog IC Technology” are Registered Trademarks of
Monolithic Power Systems, Inc.
TYPICAL APPLICATION
C3
220pF
C6
NS
C4
100nF
D1
V
OUT
3.3V
V
IN
VIN
EN
FREQ
GND
BST
5
10
1,2
5
4
8,9
3
7
SW
FB
COMP
MP4350
EN
Efficiency vs
Load Current
100
90
80
70
60
50
40
30
EFFICIENCY (%)
0 0.5 1.0 1.5 2.0 2.5
LOAD CURRENT (A)
V
OUT
=3.3V
V
IN
=12V
V
IN
=5V
MP4350 – 2.5A, 4MHz, 20V STEP-DOWN CONVERTER
MP4350 Rev. 1.0 www.MonolithicPower.com 2
5/26/2008 MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited.
© 2008 MPS. All Rights Reserved.
PACKAGE REFERENCE
Part Number* Package Temperature
MP4350DQ QFN10 (3x3)
–40°C to +85°C
*
For Tape & Reel, add suffix –Z (eg. MP4350DQ–Z)
For RoHS compliant packaging, add suffix –LF
(eg. MP4350DQ–LF–Z)
ABSOLUTE MAXIMUM RATINGS
(1)
Supply Voltage (V
IN
) .................... –0.3V to +22V
Switch Voltage (V
SW
) ........... –0.3V to V
IN
+ 0.3V
BST to SW..................................... –0.3V to +6V
All Other Pins................................. –0.3V to +6V
Junction Temperature...............................150°C
Lead Temperature ....................................260°C
Storage Temperature ..............–65°C to +150°C
Recommended Operating Conditions
(2)
Supply Voltage V
IN
........................... 4.5V to 20V
Output Voltage V
OUT
...................... +0.8V to 16V
Operating Temperature .............–40°C to +85°C
Thermal Resistance
(3)
θ
JA
θ
JC
QFN10 (3mm x 3mm) ............. 50 ...... 12... °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.
ELECTRICAL CHARACTERISTICS
V
IN
= 12V, V
EN
= 2.5V, V
COMP
= 1.4V, T
A
= +25°C, unless otherwise noted.
Parameter Symbol Condition Min Typ Max Units
Feedback Voltage V
FB
4.5V < V
IN
< 20V 0.776 0.8 0.824 V
Upper Switch On Resistance R
DS(ON)
V
BST
– V
SW
= 5V 150 m
Upper Switch Leakage V
EN
= 0V, V
SW
= 0V, V
IN
= 36V 1 µA
Current Limit Duty Cycle = 50% 2.9 3.5 A
Error Amp Voltage Gain
(4)
200 V/V
Error Amp Transconductance I
COMP
= ±3µA 40 60 80 µA/V
Error Amp Min Source current V
FB
= 0.7V 5 µA
Error Amp Min Sink current V
FB
= 0.9V –5 µA
VIN UVLO Threshold 2.7 3.0 3.3 V
VIN UVLO Hysteresis 0.35 V
Soft-Start Time
(4)
0V < V
FB
< 0.8V 1.5 ms
R
FREQ
= 45k 1.6 2 2.4 MHz
Oscillator Frequency
R
FREQ
= 18k 3.2 4 4.8 MHz
Shutdown Supply Current V
EN
= 0V 12 18 µA
Quiescent Supply Current No load, V
FB
= 0.9V 100 125 µA
Thermal Shutdown 150
°C
Thermal Shutdown Hysteresis 15
°C
Minimum Off Time
(4)
100 ns
Minimum On Time
(4)
100 ns
EN Up Threshold 1.35 1.5 1.65 V
EN Down Threshold 1.15 1.2 1.25 V
Note:
4) Guaranteed by design.
TOP VIEW
SW
SW
EN
COMP
FB
1
2
3
4
5
BST
VIN
VIN
FREQ
GND
10
9
8
7
6
EXPOSED PAD
ON BACKSIDE
MP4350 – 2.5A, 4MHz, 20V STEP-DOWN CONVERTER
MP4350 Rev. 1.0 www.MonolithicPower.com 3
5/26/2008 MPS Proprietary Information. Unauthorized Photocopy and Duplication Prohibited.
© 2008 MPS. All Rights Reserved.
PIN FUNCTIONS
Pin # Name Description
1, 2 SW
Switch Node. This is the output from the high-side switch. A low forward drop Schottky diode to
ground is required. The diode must be close to the SW pins to reduce switching spikes.
3 EN
Enable Input. Pulling this pin below the specified threshold shuts the chip down. Pulling it up
above the specified threshold or leaving it floating enables the chip.
4 COMP
Compensation. This node is the output of the error amplifier. Control loop frequency
compensation is applied to this pin.
5 FB
Feedback. This is the input to the error amplifier. An external resistive divider connected
between the output and GND which scales down V
OUT
equal to the internal +0.8V reference.
6 GND
Ground. It should be connected as close as possible to the output capacitor to shorten the high
current switch paths.
7 FREQ
Switching Frequency Program Input. Connect a resistor from this pin to ground to set the
switching frequency.
8, 9 VIN
Input Supply. This supplies power to all the internal control circuitry, including the bootstrap
regulator and the high-side switch. A decoupling capacitor to ground must be placed close to
this pin to minimize switching spikes.
10 BST
Bootstrap. This is the positive power supply for the internal floating high-side MOSFET driver.
Connect a bypass capacitor between this pin and SW pin.
TYPICAL PERFORMANCE CHARACTERISTICS
V
IN
= 12V, C1 = 10µF, C2 = 22µF, L = 10µH and T
A
= +25°C, unless otherwise noted.
Efficiency vs
Load Current
100
90
80
70
60
50
40
EFFICIENCY (%)
0 0.5 1.0 1.5 2.0 2.5
LOAD CURRENT (A)
V
OUT
=2.5V
V
IN
=12V
V
IN
=5V
V
SW
10V/div.
V
OUT
AC Coupled
10mV/div.
I
L
1A/div.
V
SW
10V/div.
V
OUT
AC Coupled
20mV/div.
I
L
1A/div.
Steady State
I
OUT
= 0.1A
Steady State
I
OUT
= 1A
Efficiency vs
Load Current
100
90
80
70
60
50
40
EFFICIENCY (%)
0 0.5 1.0 1.5 2.0 2.5
LOAD CURRENT (A)
V
OUT
=5V
V
IN
=12V
Steady State
I
OUT
= 2A
V
SW
10V/div.
V
OUT
AC Coupled
10mV/div.
I
L
1A/div.
Oscillating Frequency
vs R
freq
4000
3500
3000
2500
2000
1500
1000
500
0
OSCILLATIONG EFFICIENCY (KHz)
10 100 1000
P1-P3P4-P6P7-P9P10-P12P13-P14

MP4350DQ-LF-P

Mfr. #:
Buy MP4350DQ-LF-P
Manufacturer:
Monolithic Power Systems (MPS)
Description:
Switching Voltage Regulators 2.5A, 4MHz, 20V Nonsync Step-Down
Lifecycle:
New from this manufacturer.
Delivery:
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