Step-Up DC-DC Converter Features Start-up Voltage 0.9V Fixed

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Step-Up DC-DC Converter Features Start-up Voltage 0.9V Fixed

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APW7077/A
Step-Up DC-DC Converter
Features
Start-up Voltage 0.9V Fixed 300kHZ Operating Frequency Built-In Internal Soft Start Circuit Operating Current 3.3V (±2.5%) Fixed (APW7077) Adjustable Output Voltage (APW7077A) High Efficiency 400mA Output Current High Output Current Compact Package: SOT-23-5 Lead Free Available (RoHS Compliant)
General Description
APW7077/A series multi- function step-up DC-DC converter with adaptive voltage mode controller higher efficiency application from four cells battery packs. APW7077/A series operating mode, voltage-mode follow portable application. built-in driver pin, pin, connecting external transistor MOSFET during light load, device will automatically skip switching cycles maintain high efficiency. APW7077/A series consists controller, reference voltage, phase compensation, oscillator, soft-start, driver block. will provide operate suitable voltage without external compensation circuit. APW7077/A series have fixed voltage adjustable voltage version from wide input voltage ranges 0.7V 5.5V step-up DC-DC converter. start-up guaranteed device operating down 0.7V. providing 300mA loading current. Besides, quiescent current (switch-off) guaranteed.
Applications
Cellular Portable Phones Portable Audio Camcorders Digital Still Camera Hand-held Instrument PDAs
Pinouts
VOUT
SOT-23-5 (Top View) APW7077
SOT-23-5 (Top View) APW7077A
ANPEC reserves right make changes improve reliability manufacturability without notice, advise customers obtain latest version relevant information verify before placing orders. Copyright ANPEC Electronics Corp. Rev. Jun., 2006 www.anpec.com.tw
APW7077/A
Ordering Marking Information
APW7077/A Lead Free Code Handling Code Temp. Range Package Code Voltage Code APW7077 APW7077 77RX 77ZX Date Code, 3.3V Date Code, 5.0V Package Code SOT-23-5 Temp. Range Handling Code Plastic Tape Reel Voltage Code 3.3V 5.0V Lead Free Code Lead Free Device Blank Original Device APW7077A A77X Date Code
Note: ANPEC lead-free products contain molding compounds/die attach materials 100% matte plate termination finish; which fully compliant with RoHS compatible with both SnPb lead-free soldiering operations. ANPEC lead-free products meet exceed lead-free requirements IPC/JEDEC STD-020C classification lead-free peak reflow temperature.
Block Diagram
VOUT
Phase Compensation
Error Amp. Vref=1.0V RAMP GEN.
Controller Comp. Oscillator Driver
Voltage Reference
Soft-Start
APW7077
Phase Compensation
Controller Driver
Error Amp. RAMP GEN. Voltage Reference
Comp. Oscillator
Soft-Start
APW7077A
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APW7077/A
Absolute Maximum Ratings
Symbol TSTG VESD Supply voltage Input output pins (CE, EXT) Operating Ambient Temperature Range Junction Temperature Range Storage Temperature Range Soldering Temperature Minimum Rating Parameter Value -0.3 -0.3 +150 300, seconds Unit
Descripition
Number APW7077 APW7077A Name VOUT Function Description Chip enable input. High operating mode; shutdown mode External MOSFET transistor drive pin. Ground pins circuit. Supply voltage. Internal 1.0V reference voltage. resistor divider output voltage from VOUT internal connection pin. VOUT Provides bootstrap power
VFB.
Thermal Characteristics
Symbol Parameter Thermal Resistance Junction Ambient SOT-23-5 Value Unit °C/W
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APW7077/A
Electrical Characteristics
(for values 25°C, VOUT 3.3V, unless otherwise noted)
APW7077A
Symbol Step-Up Section
Parameter
Test Condition
Unit
Minimum Operating Input Voltage Operating Voltage Start-up Voltage
Io<10mA, VOUT (<5.5V) 12V, Io<10mA, 3.3V, 0.5V 2.0V<VDD<5.5V 0.5V
±1.2 ±0.5 -110 -150
Operating Frequency Oscillator Frequency Line Regulation
DMAX
Maximum Duty Cycle
Maximum Duty Line Regulation 2.0V<VDD<5.5V Power MOSFET ISOURCE Output Source Current ISINK Output Sink Current Control Section Output Voltage Range Feedback Voltage Feedback Voltage Line Regulation Feedback Input Current Soft-start Time Soft-start Threshold Voltage Soft-start Hysteresis Voltage IOFF Operating Current Stand-by Current Switch-off Current Logic Logic HIGH(VIH Input Current 3.3V 3.3V, 0.5V 3.3V, 1.1V 3.3V, 1.3V 3.3V, Duty External Divider ILOAD 2.0V<VDD <5.5V 1.4V 0.98 Duty -0.4V Duty 0.4V
±0.1 0.03 1.65 1.02 0.07
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APW7077/A
Electrical Characteristics (Cont.)
(for values 25°C, VOUT 3.3V, unless otherwise noted)
Symbol
Parameter
Test Condition
APW7077
Unit
Step-Up Section Minimum Operating Input Voltage Operating Voltage APW7077_33, Io<10mA Start-up Voltage APW7077_33, 10mA<Io<100mA APW7077_50, Io<10mA APW7077_50, 10mA<Io<100mA VHOLD DMAX Hold Voltage Operating Frequency Maximum Duty Cycle ILOAD 10mA VOUT 3.3VX96% VOUT 3.3VX96%
3.218 4.875 -110 1.65 VOUT, VOUT 0.96VOUT VOUT, VOUT 1.04VOUT VOUT, VOUT 1.3VOUT 2.0V 0.07 -150 3.383 5.125
Power MOSFET ISOURCE Output Source Current Duty5%, 2.9V ISINK VOUT Output Sink Current APW7077-33 APW7077-50 Soft-start Time Soft-start Threshold Voltage Duty Soft-start Hysteresis Voltage IOFF Operating Current Stand-by Current Switch-off Current Logic (VIL) Logic HIGH (VIH) Input Current Duty5%, 0.4V Control Section
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APW7077/A
Application Circuit
Application Circuit 7077
10uH/1.5A SS12 VOUT=3.3V(APW7077-33) VOUT=5V(APW7077-50) 100uF VOUT
7077
APM2300A
100uF
10uF
Application Circuit APW7077A
2.5~5.2V 4.7uF
7077A
10uH/1.5A
SS12
9~12V/50mA
10uF
=(1+R2/R1)*1.0V
0.1uF
APM2300A
820K/620K
R1/75K
/1000pF
Application Circuit APW7077A
10uH/1.5A SS12 3~5V
100uF
7077A
=(1+R2/R1)*1.0V APM2300A 10uF
100uF
R2/300K R1/75K /33pF
100K recommended
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APW7077/A
Typical Characteristics
Start-up/Hold Voltage Output Current
Start-up/Hold Voltage Output Current
Input Voltage
VSTART-up
Input Voltage
VSTART-up
Vhold
Vhold
VOUT=3.3V
VOUT=5.0V
Output Current (mA)
Output Current (mA)
Efficiency Output Current
Efficiency Output Current
DD=3V DD=2V
Efficiency(%)
DD=5V
Efficiency(%)
VOUT=12V L=10µF
VDD=3.3V
VOUT=5V L=10µH
1000
Output Current (mA)
Output Current (mA)
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APW7077/A
Typical Characteristics (Cont.)
Output Voltage Output Current
Output Voltage Output Current
3.315
Output Voltage
3.305
Output Voltage
VIN=2.5V
VIN=3.0V
3.295
VIN=1.2V
VIN=2.0V
VIN=1.2V
VIN=2.0V VOUT=5.0V
3.285
VOUT=3.3V
Output Current (mA)
Output Current (mA)
Output Voltage Temperature
Oscillation Frequency Temperature
Oscillation Frequency (kHz)
Output Voltage
Temperature (°C)
Temperature (°C)
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APW7077/A
Typical Characteristics (Cont.)
Load Transient Waveform
Load Transient Waveform
VIN=3.3V, VOUT=12V, IOUT=5mA->50mA->5mA L=10µH, COUT=4.7µF+0.1µF, Cff=560pF CH1:VOUT, 100mV/DIV, Time=1ms/DIV CH4:IOUT, 20mA/DIV
VIN=3.3V, VOUT=5V, IOUT=10mA->300mA->10mA L=10µH, COUT=22µF+22µF+0.1µF, Cff=33pF CH1:VOUT, 100mV/DIV, Time=1ms/DIV CH4:IOUT, 200mA/DIV
Driving Current Supply Voltage
Rds,on Supply Voltage
Sink/Source Current (mA)
ISINK (EXT=0.4V) ISOURCE (EXT=VDD-0.4V)
Rds,on resistance
Supply Voltage
Supply Voltage
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APW7077/A
Typical Characteristics (Cont.)
Supply Current Supply Voltage
Feedback Voltage Supply Voltage
Switching Mode
Feedback Voltage
Supply Current (µA)
Switching Mode
Supply Voltage
Supply Voltage
Oscillation Frequency Supply Voltage
Maximum Duty Supply Voltage
Oscillation Frequency (kHz)
Maximum Duty
Supply Voltage
Supply Voltage
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APW7077/A
Typical Characteristics (Cont.)
Feedback Voltage Temperature
1.020
1.015
Feedback Voltage
1.010
1.005
1.000
0.995
0.990
0.985
0.980
Temperature (°C)
Function Description
Operation APW7077/A series noise fixed frequency voltage-mode DC-DC controllers, consist start-up circuit, reference voltage, oscillator, loop compensation network, control circuit, resistance driver. APW7077 provide on-chip feedback resistor loop compensation network, system designer regulated fixed output voltage 3.3V 5.0V with small number external components, optimized battery powered portable products where large output current required. APW7077A provide internal reference voltage 1.0V output voltage setting external resistance higher voltage requirement. quiescent current typically 120uA (VOUT 3.3V, 300kHz), further reduced about 1.0uA when chip disabled (VCE 0.7V).
Copyright ANPEC Electronics Corp. Rev. Jun., 2006
APW7077/A operation best understood referring block diagram. error amplifier monitors output voltage feedback resistor divider comparing feedback voltage with reference voltage. When feedback voltage lower than reference voltage, error amplifier output will decrease. error amplifier output then compared with oscillator ramp voltage controller. When feedback voltage higher than reference voltage, error amplifier output increases duty cycle decreases. When external power switch current ramps inductor, storing energy magnetic field. When external power switch off, energy stored magnetic field transferred output filter capacitor load. output filter capacitor stores charge while
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APW7077/A
Function Description (Cont.)
Operation (Cont.) inductor current higher than output current, then sustains output voltage until next switching cycle. load current decreased, switch transistor turns shorter duty cycle. Under light load condition, controller will skip switching cycles reduce power consumption, that high efficiency maintained light loads. Fixed Output Voltage (for APW7077 only) APW7077 VOUT integrate feedback resistor network. This trimmed selected voltage with accuracy +/-2.5%. Setting Output Voltage (for APW7077A only) APW7077A, output voltage adjustable. output voltage using resistor divider connected output shown typical operating circuit. internal reference voltage 1.0V with variation, ratio feedback resistors sets output voltage according following equation:
1.0V
ramp output voltage reach setting voltage without over shooting issue whenever heavy load light load condition. soft start time 25ms setting internal circuit. Oscillator oscillator frequency internally accuracy +/-10% with temperature coefficient 3.3%/°C. Enable/Disable Operation APW7077/A series offer shutdown mode chip enable pin) reduce current consumption. When voltage greater than chip will enabled, which means controller normal operation. When voltage less than chip disabled, which means shutdown quiescent current become 1uA. pull high VDD(or VOUT) internal resistor, this resistance greater than this chip will enable normally when floating. Important: apply voltage between 0.7V this pin' hysteresis voltage range. Clearly defined output states only obtained applying voltage this range. Compensation device designed operate continuous conduction mode. internal compensation circuit designed guarantee stability over full input/output voltage full output load range. Step-up Converter Operating Mode step-up DC-DC controller designed operate continuous conduction mode (CCM) discontinuous conduction mode (DCM). step converter CCM, duty cycle
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avoid thermal noise from feedback resistor, (R1+R2) resistance smaller than variation recommended. Soft Start There soft start function integration APW7077/A series avoid over shooting when power When power applied device, soft start circuit first pumps output voltage VDD(or VOUT) approximately 1.65V fixed duty cycle 50%. This voltage level which controller operate normally. When supply voltage more than 1.65V internal reference voltage will
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APW7077/A
Function Description (Cont.)
Step-up Converter Operating Mode (Cont.) given
higher output voltage small output current
inductor peak current calculated
NOTES:
On-time duty cycle Average inductor current Peak inductor current Desired output current Nominal operating input voltage VOUT Desired output voltage Equivalent series resistance output capacitor Inductor Selection APW7077/A series designed work well with 12uH inductors most applications 10uH sufficiently value allow small surface mount coil, large enough maintain ripple. Lower inductance values supply higher output current, also increase ripple reduce efficiency. Higher inductor values reduce ripple improve efficiency, also limit output current. inductor should have small DCR, usually less than 0.2, minimize loss. necessary choose inductor with saturation current greater than peak current which inductor will encounter application. inductor ripple current important reasons. reason because peak switch current will average inductor current (IL) plus side note, discontinuous operation occurs when inductor current falls zero during switching cycle, greater than average inductor current. Therefore, continuous conduction mode occurs
application, step-up DC-DC controller operated discontinuous conduction mode almost. step-up converter DCM, duty cycle given
LOAD
External components values calculated from these equations, however, optimized value should obtained through experimental results. Critical Inductance Value minimum value inductor maintain continuous conduction mode determined following equation.
Ratio
system designed operate continuous mode load currents above certain level usually (Ratio define 0.2~0.5) full load minimum input voltage. When smaller than (IO*Ratio), controller system will into DCM. ripple current flowing through inductor, which affects output voltage ripple core losses. Based 20%(Ratio=0.2) current ripple, VOUT=5V, IO=1A =1.8V system, inductance value calculated 6.9uH 6.8uH inductor used. inductor current ripple expression
(max) (min)
maximum input current calculated
(max)
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APW7077/A
Function Description (Cont.)
Inductor Selection (Cont.) when less than average inductor current. Care must taken make sure that switch will reach current limit during normal operation. inductor must also sized accordingly. should have saturation current rating higher than peak inductor current expected. output voltage ripple also affected total ripple current. Output Capacitor output capacitor used sustaining output voltage when external MOSFET bipolar transistor switched smoothing ripple voltage. output capacitance needed calculated equations. regulator will loaded uniformly, with very little load changes, lower current outputs, input capacitor size often reduced. size also reduced input regulator very close source output. size will generally need larger applications where regulator supplying nearly maximum rated output large load steps expected. minimum value 10µF should used less stressful conditions while 22µF 47µF capacitor required higher power dynamic loads. Small Tantalum ceramic capacitor should suitable total input ripple voltage calculated
Design Example supposed that step-up DC-DC controller with output delivering maximum 1000 output current with output ripple voltage powering from input designed. Design parameters: VOUT VOUT fsw= Ratio (typical small output ripple voltage) Assume diode forward voltage transistor saturation voltage both 0.3V. Determine maximum steady state duty cycle D=0.273 Calculate maximum inductance value which generate desired current output preferred delta inductor current average inductor current ratio: L=10uH
COUT (min)
IO(max) VOUT
also important because determines peak peak output voltage ripple according approximate equation:
VOUT
With output voltage ripple, capacitor should used reduce output ripple voltage. general, 100uF 220uF (0.10 0.30) Tantalum capacitor should appropriate. choice output capacitors also somewhat arbitrary depends design requirements output voltage ripple. minimum value 10µF recommended increased larger value. Input Capacitor input capacitor stabilize input voltage minimize peak current ripple from source. size used dependant application board layout.
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Function Description (Cont.)
Design Example(Cont.) Determine average inductor current peak inductor current: IL=1.38A IL=0.218A Ipk=1.45A Therefore, inductor with saturation current larger than 1.73 selected initial trial. Determine output capacitance value desired output ripple voltage: COUT=33uF output capacitor 0.05. Therefore, Tantalum capacitor with value 47uF 0.05 used output capacitor. However, according experimental result, 220uF output capacitor gives better overall operational stability smaller ripple voltage.
Component Selection
Diode Selection output diode boost regulator must chosen correctly depending output voltage output current. diode must rated reverse voltage equal greater than output voltage used. average current rating must greater than maximum load current expected, peak current rating must greater than peak inductor current. During short circuit testing, short circuit conditions possible application, diode current rating must exceed switch current limit. diode largest source loss DC-DC converters. most importance parameters which affect their efficiency forward voltage drop, reverse recovery time, trr. forward voltage drop creates loss just having voltage across device while current flowing through reverse recovery time generates loss when diode reverse biased, current appears actually flow backwards through diode minority carriers being swept from junction. Using Schottky diodes with lower forward voltage drop will decrease power dissipation increase efficiency. External Switch Transistor APW7077/A drive 110mA gate drive current. N-channel MOSFET with relatively threshold voltage, gate charge RDS(ON) required optimize overall circuit performance. APW7077/A Evaluation Board uses APM2300A. This NMOS device chosen because demonstrates RDS_ON 45mO total gate charge 12nC (typ.).
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Layout Considerations
Ground Plane point grounding should used output power return ground, input power return ground, device switch ground reduce noise. input ground output ground traces must thick enough current flow through reducing ground bounce. Power Signal Traces resistance conducting paths should used power carrying traces reduce power loss improve efficiency (short thick traces connecting inductor also reduce stray inductance). Trace connections made inductor schottky diode should minimized reduce power dissipation increase overall efficiency. Output Capacitor output capacitor should placed close output terminals obtain better smoothing effect output ripple. output capacitor, COUT, should also placed close diode. copper trace connections COUT capacitor increase series resistance, which directly effects output voltage ripple Surface mount board layout critical portion efficiency. Switching Noise Decoupling Capacitor APW7077 fixed voltage application, 0.1µF ceramic capacitor should placed close VOUT chip filter switching spikes output voltage monitored VOUT pin. Feedback Network APW7077A application, feedback networks should connected directly dedicated analog ground plane this ground plane must connect pin. analog ground plane available
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then this ground must directly pin. feedback network, resistors should kept close pin, away from inductor, minimize copper trace connections that inject noise into system.Prevent connect feedback network output decoupling MLCC. Input Capacitor APW7077A high output voltage application circuit, input voltage (VIN) tied chip supply (VDD). input capacitor must placed close This will reduce copper trace resistance which effects input voltage ripple additional input voltage filtering, capacitor placed parallel with CIN, close pin, shunt high frequency noise ground.
Inductor
minimize copper trace connections that inject noise into system, inductor, switch Schottky diode should placed close possible minimize noise coupling into other circuits. MINIMUM RECOMMENDED FOOTPRINT SURFACE MOUNTED APPLICATIONS
total design. footprint semiconductor packages must correct size insure proper solder connection interface between board package. With correct geometry, packages will self align when subjected solder reflow process.
APW7077/A
Layout Considerations (Cont.)
MINIMUM RECOMMENDED FOOTPRINT SURFACE MOUNTED APPLICATIONS (Cont.)
Bottom Layer
Demo Board Circuit Layout
1600
Layer
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1300mil
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APW7077/A
Packaging Information
SOT-23-5
Millimeters Min. 0.95 0.05 0.90 0.35 0.95 1.90 0.35 0.20 0.020 0.55 0.014 Max. 1.45 0.15 1.30 0.55 3.00 3.00 1.70 Min. 0.037 0.002 0.035 0.0138 0.110 0.102 0.059
Inches Max. 0.057 0.006 0.051 0.0217 0.118 0.118 0.067 0.037 0.075 0.022 0.008 0.028
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APW7077/A
Physical Specifications
Terminal Material Lead Solderability Solder-Plated Copper (Solder Material 90/10 63/37 SnPb), 100%Sn Meets Specification RSI86-91, ANSI/J-STD-002 Category
Reflow Condition
(IR/Convection Reflow)
Ramp-up
Critical Zone
Temperature
Tsmax
Tsmin Ramp-down Preheat
Peak
Classificatin Reflow Profiles
Profile Feature Average ramp-up rate Preheat Temperature (Tsmin) Temperature (Tsmax) Time (min max) (ts) Time maintained above: Temperature (TL) Time (tL) Peak/Classificatioon Temperature (Tp) Time within actual Peak Temperature (tp) Ramp-down Rate Sn-Pb Eutectic Assembly 3°C/second max. 100°C 150°C 60-120 seconds 183°C 60-150 seconds table 10-30 seconds Pb-Free Assembly 3°C/second max. 150°C 200°C 60-180 seconds 217°C 60-150 seconds table 20-40 seconds
6°C/second max. 6°C/second max. minutes max. minutes max. Time 25°C Peak Temperature Notes: temperatures refer topside package .Measured body surface.
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APW7077/A
Classificatin Reflow Profiles(Cont.)
Table SnPb Entectic Process Package Peak Reflow Temperatures Package Thickness Volum Volume <350 <2.5 +0/-5°C +0/-5°C +0/-5°C +0/-5°C Table Pb-free Process Package Classification Reflow Temperatures Package Thickness Volume Volume Volume <350 350-2000 >2000 <1.6 +0°C* +0°C* +0°C* +0°C* +0°C* +0°C* +0°C* +0°C* +0°C* *Tolerance: device manufacturer/supplier shall assure process compatibility including stated classification temperature (this means Peak reflow temperature +0°C. example 260°C+0°C) rated level.
Reliability test program
Test item SOLDERABILITY HOLT Latch-Up Method MIL-STD-883D-2003 MIL-STD-883D-1005.7 JESD-22-B,A102 MIL-STD-883D-1011.9 MIL-STD-883D-3015.7 JESD Description 245°C, 1000 Bias @125°C Hrs, 100%RH, 121°C -65°C~150°C, Cycles VHBM 2KV, 200V 10ms, 100mA
Carrier Tape Reel Dimensions
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APW7077/A
Carrier Tape Reel Dimensions(Cont.)
Application
178±1
1.5±
8.0±0.3
1.4±
1.75± 0.2±0.03
13.0 0.15 +0.1
SOT-23-5
0.05 +0.1
3.15 3.2±
(mm)
Cover Tape Dimensions
Application SOT-23-5 Carrier Width Cover Tape Width Devices Reel 3000
Customer Service
Anpec Electronics Corp. Head Office No.6, Dusing Road, SBIP, Hsin-Chu, Taiwan, R.O.C. 886-3-5642000 886-3-5642050 Taipei Branch 137, Lane 235, Chiao Rd., Hsin Tien City, Taipei Hsien, Taiwan, 886-2-89191368 886-2-89191369
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Step-Up DC-DC Converter Features Start-up Voltage 0.9V Fixed

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