Step-Up Converter Series White LEDs Driver Features Input Voltage
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APW7071
Step-Up Converter Series White LEDs Driver Features
Input Voltage Range 400mA Internal Switch Current 1MHz Switching Frequency 70µA Typical Load Quiescent Current 0.1µA Typical Shutdown Current Internal Soft-start efficiency Operating Output Capacitor down 0.1µF Over Voltage Protection included Lead Free Available (RoHS Compliant)
General Description
APW7071 high frequency step-up DC/DC converter small 6-lead SOT23 package specially designed drive white LEDs with constant current. device drive LEDs series from Li-Ion cell. APW7071 ideal panels requiring current high efficiency well white applications cellular phone back-lighting.
Configuration
Applications
Cellar Phones White Back Light PDAs, Handheld Computers Digital Still Cameras Players Receivers
SOT23-6 (Top View)
Ordering Marking Information
APW7071 Lead Free Code Handling Code Temperature Range Package Code Package Code SOT23-6 Operating Ambient Temperature Range 85°C Handling Code Tape Reel Plastic Lead Free Code Lead Free Device Blank Original Device Date Code
APW7071C
W71X
Notes 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 soldering operations. ANPEC leadfree products meet exceed lead-free requirements IPC/JEDEC STD-020C classification lead-free peak reflow temperature. 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. Mar., 2007 www.anpec.com.tw
APW7071
Absolute Maximum Ratings
Symbol Input Supply voltage Voltage pins SHDN VOVP TSTG TSDR VESD Voltage Switch Voltage Junction Temperature Range Storage Temperature Range Maximum Soldering Temperature, Seconds Minimum Rating (Human Body Mode) (Note Parameter Rating -0.3 -0.3 VIN+0.3 -0.3 -0.3 ~150 Unit
Note Absolute Maximum Ratings those values beyond which life device impaired. Exposure absolute maximum rating conditions extended periods affect device reliability. Note device sensitive. Handling precautions recommended.
Thermal Characteristics
Symbol Parameter Junction-to-Ambient Resistance free (Note Value Unit °C/W
Note measured with component mounted high effective thermal conductivity test board free air.
Recommended Operating Conditions (Note
Value Symbol VOUT COUT Input supply voltage Switch voltage Output Voltage Inductor Input capacitor Output capacitor Operating ambient temperature Operating junction temperature Parameter Min. Typ. -Max. Unit
Note Please refer Typical Application Circuit
Copyright ANPEC Electronics Corp. Rev. Mar., 2007
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APW7071
Electrical Characteristics
VIN=3.3V, SHDN=VIN, -40°C +85°C, typical values TA=+25°C (unless otherwise noted).
APW7071 Symbol Parameter Test Condition Min. Supply Voltage Current (Cont.) IQ_SD UVLO Input Voltage Range Operating quiescent current Shutdown current Under-Voltage Lockout threshold Under-Voltage Lockout hysteresis ENABLE SHDN high level input voltage SHDN level input voltage SHDN input leakage current SHDN=GND IOUT=0, switching, VFB=0.3V SHDN=GND Typ. Max. Unit
Power Switch Current limit toff Rdson Maximum switching voltage Minimum off-time Maximum on-time MOSFET on-resistance MOSFET leakage current ILIM OUTPUT VOUT VREF Adjustable output voltage range Feedback input bias current Feedback trip point voltage threshold hysteresis IOVP input current Leakage current VOVP=15V SHDN=GND, VOVP=6V VFB=1.3V 2.5VIN6.0V 0.237 0.25 0.263 18.5 MOSFET current limit VIN=2.5V, =200mA =19V 1000
Copyright ANPEC Electronics Corp. Rev. Mar., 2007
www.anpec.com.tw
APW7071
Typical Operating Characteristics
(Circuit Figure 3.3V, ILED 20mA, 4.7µH, 4.7µF, COUT 0.1µF,4 LEDs, +25°C, unless otherwise noted.) Efficiency Current
VIN=4.2V VIN=3.6V
Efficiency Supply Voltage
Efficiency(%)
Efficiency(%)
VIN=2.7V
ILED=15mA
Current(mA)
Supply Voltage
Switch Resistance Supply Voltage
Switch Resistance Junction Temperature
Swiitch Resistaance
Switch Resistance
VIN=3.3V
Supply Voltage
Junction Temperature (°C)
No-Switching Quiescent Current Supply Voltage
Current Supply Voltage
No-Switching Quiescent Current (µA)
Current (mA)
L=4.7µH COUT=0.1µF LEDs
Supply Voltage Copyright ANPEC Electronics Corp. Rev. Mar., 2007
Supply Voltage www.anpec.com.tw
APW7071
Operating Waveforms
(Circuit Figure 3.3V, ILED 20mA, 4.7µH, 4.7µF, COUT 0.1µF,4 LEDs, +25°C, unless otherwise noted.) Start-up Waveform
VSHDN
Waveform
VOUT
VOUT
CH1: VSHDN, 2V/Div, CH2: VOUT, 5V/Div, CH3: IIN, 100mA/Div, Time: 1ms/Div
CH1: VOUT, 5V/Div, Time: 20ms/Div
Operation
Pulse Burst Operation
CH1: VOUT, 200mV/Div, CH2: VSW, 10V/Div, CH3: VFB, 100mA/Div, Time: 1µs/Div
CH1: VOUT, 200mV/Div, CH2: VSW, 10V/Div, CH3: VFB, 100mA/Div, Time: 2µs/Div
Copyright ANPEC Electronics Corp. Rev. Mar., 2007
www.anpec.com.tw
APW7071
Descriptions
Name SHDN Function Switch Pin. Connect this inductor/diode here. Ground Pin. Feedback Pin. Reference voltage 0.25V. Connect this cathode lowest resistor (RFB). Calculate resistor value according 0.25V/lLED Shutdown Pin. Pulling this ground forces device into shutdown mode reducing supply current less than 1µA. This should left floating. Over voltage protection sense pin. Connect this output capacitor. Left unconnected disable function. Supply voltage Pin.
Block Diagram
Under Voltage Lockout 400ns Min. off-time SHDN Comparator
Error Comparator
VREF=0.25V
Control Logic
Gate Driver
N-MOSFET
Max. on-time
Current Limit RSENSE
SHDN
Soft start
Copyright ANPEC Electronics Corp. Rev. Mar., 2007
www.anpec.com.tw
APW7071
Typical Application Circuit
2.7V~6V 4.7µF
4.7µH
MSCD052
VOUT
0.1µF
SHDN
Fig.1 Typical LEDs application Using more output capacitors with larger capacitance like reduce ripple current well improve line regulation.
Copyright ANPEC Electronics Corp. Rev. Mar., 2007
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APW7071
Function Descriptions
Operation APW7071 operates pulse frequency modulation (PFM) scheme with constant peak current control. operation understood referring Block Diagram. converter keeps monitoring output voltage through resistor-divider connected with VOUT. When feedback voltage falls below reference voltage (typical 0.25V), internal switch turns inductor current ramps switch turns inductor current reaches internal peak current limit (400mA typical). second criterion that turns switch maximum on-time control. switch off, external Schottky diode forwards bias, that current delivered output. switch remains minimum (typical), wouldn' turned again until feedback voltage drops below reference voltage. This regulation scheme allows wider selection range inductor output capacitor. Shutdown Driving SHDN ground places shutdown. When shutdown, internal power MOSFET turns off, internal circuitry shuts down quiescent supply current reduces <0.1µA (typical). Soft Start APW7071 limits this inrush current increasing current limit start-up. Under Voltage Lockout Transients cuase system damage failure when powering undergoing instantaneous glitches supply voltage. Then, undervoltage lockout circuit turns main switch prevent malfunction input voltage. Over Voltage Protection driving applications, feedback voltage falls down LEDs, series, failed. Meanwhile, converter unceasingly boosts output voltage like open-loop operation. Therefore, overvoltage protection (OVP), monitoring output voltage pin, integrated into chip prevent output voltages from exceeding their maximum voltage ratings. When voltage rises above threshold (17V typical), converter stops switching prevents output voltage from rising. converter work again when voltage falls below voltage threshold.
Copyright ANPEC Electronics Corp. Rev. Mar., 2007
www.anpec.com.tw
APW7071
Application Information
Setting LEDs Current fig. converter regulates voltage pin, connected with cathod lowest current-sense resistor 0.25V(typical). Therefore current (ILED), flowing LEDs calculated following equation:
ILED 0.25V
Using signal apply SHDN external signal applied SHDN cyclically turns converter. average current through LEDs will increase proportionally duty cycle signal. soft start duration, signal with frequency from 100Hz 300Hz recommended.
2.7V~6V 4.7µF 4.7µH 0.1µF 100Hz~300Hz brightness control MSCD052 VOUT
Brightness Control brightness LEDs controlled adjusting current. There three following recommended methods adjust brightness LEDs Using adjustable voltage applied shown fig. additional network connected between junction cathode adjustable voltage (VADJ connected with injects constant current (I1, I1=(VADJ-0.25V)/R3) into node when voltage regulated 0.25V. Therefore voltage across reduced offset voltage (I1xR2), reducing current brightness. current calculated following equation: 0.25V VADJ 0.25
SHDN
Duty=100%, LED=20mA Duty=0%,
Fig. Brightness Control applying signal SHDN Using filtered signal fig. brightness control achieved applying signal filter generate filtered signal instead VADJ. signal with frequency above 5KHz recommended.
2.7V~6V 4.7µF 4.7µH 0.1µF MSCD052 VOUT
ILED
With VADJ from 3.3V, current controlled from 20mA.
2.7V~6V 4.7µF 4.7µH 0.1µF MSCD052 VOUT
SHDN
120K
0.1uF
3.3V brightness control Duty=100%, Duty=0%, LED=20mA
SHDN
120K
Fig. Brightness Control filtered signal
Inductor Selection inductor together with load current (IOUT), internal peak current (IPK), input (VIN) output voltage (VOUT) application determines switching frequency
VADJ=3.3V, VADJ=0V, LED=20mA
Fig. Brightness Control adjustable voltage
Copyright ANPEC Electronics Corp. Rev. Mar., 2007
www.anpec.com.tw
APW7071
Application Information (Cont.)
Inductor Selection (Cont.) converter. switching frequency calculated
IOUT (VOUT
Recommended inductors
Part LQH31CN2R2M03L LQH32CN4R7M23L SH30184R7YSB LQH32CN100K53L SH3018100YSB Value (µH) Vendor Murata Murata Murata
where foward voltage Schottky diode.
Output capacitor selection smaller inductor gets higher switching frequency lower efficiency. operate under discontinuous conduction mode, inductor selected below:
TOFF,MIN (VOUT
better output voltage filtering, output capacitor like ceramic capacitors recommended. selection output capacitance directly influences output voltage ripple converter. output voltage ripple calculated
VOUT IOUT VOUT
white applications, inductor values between recommended. inductor also affects maximum output power. maximum output current calculated
IOUT ,MAX TOFF IIN,AVG VOUT VOUT
white applications, output ripple proportional current. proper output capacitor from 0.1µF recommended limit maximum current ripple current. Recommended output capacitor
where
TOFF
VOUT
Part GRM188R61E105KA12
Value 1.0µF/X5R/0603/25V 0.22µF 0.1µF
Vender Murata
OFF,
0.4µs (typical)
understood following figure.
Input capacitor selection good input voltage filtering, ceramic capacitors recommended. 4.7µF ceramic input capacitor sufficient most applications. better-input voltage filtering capacitor value increased. Recommended input capacitor
Part Value 4.7µF/X5R/0603/6.3V 10µF/X5R/0805/6.3V Vender Murata Murata GRM188R60J475KE19D GRM219R60J106KE19D
Toff Toff,min
Fig.5 Discontinuous Conduction Mode Operation Waveform efficiency estimated section "Typical Operating Characteristics".
Diode selection achieve high efficiency, Schottky diode must used. current rating diode must meet peak current rating converter.
Copyright ANPEC Electronics Corp. Rev. Mar., 2007
www.anpec.com.tw
APW7071
Application Information (Cont.)
Diode selection (Cont.) Recommended diode
Part MSCD052 Reverse Voltage Vender Zowie
Layout considerations switching power supplies especially with high peak currents switching frequency, layout important step design. layout carefully done, regulator show noise problems duty cycle jitter. 1.The input capacitor must placed close device, which reduce copper trace resistance effect input ripple 2.The inductor diode should placed close possible switch minimize switching noise. 3.The feedback feedback network should away from inductor shielded ground plane trace minimize noise.
Copyright ANPEC Electronics Corp. Rev. Mar., 2007
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APW7071
Package Information
SOT23-6
VIEW
0.25 GAUGE PLANE SEATING PLANE VIEW
SOT23-6 MILLIMETERS MIN. MAX. 1.45 0.00 0.90 0.30 0.08 2.90 2.80 1.60 0.95 1.90 0.30 0.60 0.012 0.15 1.30 0.50 0.22 0.000 0.035 0.012 0.003 0.114 0.110 0.063 0.037 0.075 0.024 MIN. INCHES MAX. 0.057 0.006 0.051 0.020 0.009
Copyright ANPEC Electronics Corp. Rev. Mar., 2007
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APW7071
Carrier Tape Reel Dimensions
Application
1.5±
3.2±
1.4±
1.75± 0.2±0.033 (mm)
13.0 0.15 1.5±
SOT23-6
0.05
3.15
Cover Tape Dimensions
Application SOT23-6
Carrier Width
Cover Tape Width
Devices Reel 3000
Copyright ANPEC Electronics Corp. Rev. Mar., 2007
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APW7071
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
Classification 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/Classification 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.
Copyright ANPEC Electronics Corp. Rev. Mar., 2007 www.anpec.com.tw
APW7071
Classification Reflow Profiles (Cont.)
Table SnPb Entectic Process Package Peak Reflow Temperatures Package Thickness Volum Volum <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 Volum Volum Volum <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 exam 260°C+0 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
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
Copyright ANPEC Electronics Corp. Rev. Mar., 2007
www.anpec.com.tw
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