POWER LP3308 1.4mhzfixed-frequency pwm operation Datasheet

Preliminary Datasheet
LP3308
1.4MHz,30V/1.3A High Performance, Boost Converter
Features
General Description
The LP3308 is a 1.4MHz PWM boost switching
regulator designed for constant-voltage boost
applications. The LP3308 can drive a string of up to
30V. The LP3308 implements a constant frequency
1.4MHz PWM control scheme. The high frequency
PWM operation also saves board space by reducing
external component sizes. To improve efficiency, the
feedback voltage is set to 1230 mV, which reduces
the power dissipation in the voltage setting resistor.
Highly integration and internal compensation
network minimizes as 5 external component counts.
Optimized operation frequency can meet the
requirement of small LC filters value and low
operation current with high efficiency.
High Efficiency: 90% 
1.4MHzFixed-Frequency PWM Operation
Maximum Output Voltage up to 30V
Guaranteed 13V/200mA Output with 5V input
Operating Range : 2.7V to 5.5V
Shutdown Supply Current:<1uA 
Programmable Soft-star
Available in TSOT23-6/SOT23-5 Package 
Minimize the External Component
RoHS Compliant and 100% Lead (Pb)-Free
Applications
Panel Bais Voltage supply
OLED Backlight driver
Notebook Computers
Portable Applications
MID/PTV
Ordering Information
LP3308
Typical Application Circuit
Vin
F: Pb-Free
Pin Configurations
6
1
D1
SS0520
LX
LP3308
FB
SHDN
SS
R1
860K
3
5
R2
100K
C4
33nF
2
4
C2
4.7uF
C3/NC
100pF
Vin
GND
Package:
B5: SOT23-5
B6: TSOT23-6
10uH
C1
4.7uF
Marking information
(TSOT23-6)
Please view website.
(SOT23-5)
LP3308– 00 Version1.0 Datasheet
Feb.-2010
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Preliminary Datasheet
LP3308
Functional pin description
SOT-23-5
SOT-23-6
Pin Name
Pin Function
1
1
LX
Switch Pin. Connect this Pin to inductor and catch diode. Minimize the track
area to reduce EMI.
2
2
GND
Ground Pin
3
3
FB
Feedback Reference Voltage Pin. Series connect a resistor between Vout and
ground as a voltage sense. The feedback voltage is 1230mV.
4
/SHDN
Chip Enable (Active High). Voltage sensing input to trigger the function of
over voltage protection. Note that this pin is high impedance. There should
be a pull low 100kΩ resistor connected to GND when the control signal is
floating.
5
SS
Softstar pin. Leave SS open to disable the soft-star function.
6
Vin
Supply Input Voltage Pin. Bypass 1uF capacitor to GND to reduce the input
noise.
4
5
Function Block Diagram
LP3308– 00 Version1.0 Datasheet
Feb.-2010
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Page 2 of 9
Preliminary Datasheet
LP3308
Absolute Maximum Ratings
Supply Input Voltage---------------------------------------------------------------------------------------------------−0.3V to 6.0V
LX Input Voltage --------------------------------------------------------------------------------------------------------−0.3V to 33V
The Other Pins ----------------------------------------------------------------------------------------------------------−0.3V to 5.5V
Power Dissipation, PD @ TA = 25°C TSOT-23-5/6-----------------------------------------------------------------------0.455W
Lead Temperature (Soldering, 10 sec.) -------------------------------------------------------------------------------- 260°C
Operation Temperature Range ---------------------------------------------------------------------------------−40°C to 80°C
Storage Temperature Range ----------------------------------------------------------------------------------------−65°C to 150°C
Electrical Characteristics
Parameter
Symbol
Test Condition
Min
Typ.
Max
Units
6
V
System Supply Input
Operation voltage Range
VDD
2.7
Under Voltage Lock Out
VDD
2.2
Supply Current
IDD
FB=0.2V, Switch
430
550
uA
Shut Down Current
IDD
VEN < 0.4V
0.1
1
uA
Line Regulation
VIN : 3.0~4.3V
2.4
2.6
V
2
%
1.4
MHz
Oscillator
Operation Frequency
FOSC
Maximum Duty Cycle
Feedback Voltage
93
LP3308
1.21
%
1.23
1.255
V
MOSFET
On Resistance of MOSFET
RDS(ON)
0.7
Ω
SW Current Limit
ILM
1.4
A
Protection
Shut Down Voltage
VEN
Enable on Voltage
VEN
LP3308– 00 Version1.0 Datasheet
Feb.-2010
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V
1.0
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V
Page 3 of 9
Preliminary Datasheet
LP3308
Typical Operating Characteristics
LP3308– 00 Version1.0 Datasheet
Feb.-2010
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Preliminary Datasheet
LP3308– 00 Version1.0 Datasheet
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LP3308
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LP3308– 00 Version1.0 Datasheet
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LP3308
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Preliminary Datasheet
LP3308
Applications Information
Inductor Selection
The recommended value of inductor for 30V applications are 4.7 to 22µH. Small size and better efficiency
are the major concerns for portable device, such as LP3308 used for mobile phone. The inductor should have
low core loss at 1.4MHz and low DCR for better efficiency. To avoid inductor saturation current rating
should be considered.
LP3308– 00 Version1.0 Datasheet
Feb.-2010
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Preliminary Datasheet
LP3308
Packing information
LP3308– 00 Version1.0 Datasheet
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Preliminary Datasheet
LP3308– 00 Version1.0 Datasheet
Feb.-2010
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LP3308
Page 9 of 9
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