General Description AS1322A AS1322B synchronous, fixed frequency,
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AS1322
General Description
AS1322A AS1322B synchronous, fixed frequency, very high-efficiency DC-DC boost converters capable supplying 3.3V 150mA from single AAsupply. Compact size minimum external parts requirements make these devices perfect modern portable devices. High-speed switching frequency (1.2MHz) internally compensated current mode design provide highlyreliable DC-DC conversion, especially when driving white LEDs. converters available standard products listed Table Table Standard Products Model AS1322A AS1322B Light Load Switching Automatic Powersave Operation Continuous Switching
Features
Efficiency Single-Cell Operation Delivers 150mA 3.3V (from Single Cell) Delivers 500mA 3.3V (from Cells) Start-Up Voltage: 0.85V High-Speed Fixed-Frequency: 1.2MHz Internal PMOS Synchronous Rectifier Automatic Powersave Operation (AS1322A) Continuous Switching Light Loads (AS1322B) Anti-Ringing Control Minimizes Logic Controlled Shutdown 1µA) Output Range: 5.0V 6-pin TSOT-23 Package
devices contain internal MOSFET switches: NMOS switch PMOS synchronous rectifier. Anti-ringing control circuitry reduces damping inductor discontinuous mode, devices exhibit extremely quiescent current 1µA) shutdown. AS1322 available 6-pin TSOT-23 package.
Applications
AS1322 ideal low-power applications where ultra-small size critical medical diagnostic equipment, hand-held instruments, pagers, digital cameras, remote wireless transmitters, players, bias supplies, cordless phones, receivers, cards.
Figure Typical Application Diagram Single Cell 3.3V Synchronous Boost Converter
10µH
Battery 10µF
VOUT
AS1322
1.02M
10µF
VOUT 3.3V 150mA
SHDNN
604k
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AS1322 Data Sheet
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Descriptions
Assignments
Figure Assignments (Top View)
AS1322
VOUT
SHDNN
Descriptions
Table Descriptions Name Number Description Switch Pin. Connect inductor between this VIN. Keep trace lengths short wide practical reduce voltage overshoot. inductor current falls zero, SHDNN low, internal anti-ringing switch connected from this minimize EMI. Note: optional Schottky diode connected between this VOUT. Signal Power Ground. Provide short, direct path between this negative side output capacitor(s). Feedback Pin. Feedback input error amplifier. Connect resistor divider this pin. output voltage adjusted from VOUT 1.23V[1 (R1/R2)] Shutdown Pin. Logic controlled shutdown input. Normal operation, 1.2MHz typical operating frequency. Shutdown; quiescent current <1µA. SHDNN undefined, ring. Note: typical application, SHDNN should connected through pull-up resistor. Output Voltage Sense Input Drain Internal PMOS Synchronous Rectifier. Bias derived from VOUT when VOUT exceeds VIN. trace length from VOUT output filter capacitor(s) should short wide practical. protection diode internal PMOS synchronous rectifier, VOUT held 0.6V during shutdown. Input Voltage. AS1322 gets start-up bias from unless VOUT exceeds VIN, which case bias derived from VOUT. Thus, once started, operation completely independent from VIN. Operation only limited output power level internal series resistance supply.
SHDNN
VOUT
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AS1322 Data Sheet
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Descriptions
Absolute Maximum Ratings
Stresses beyond those listed Table cause permanent damage device. These stress ratings only, functional operation device these other conditions beyond those indicated Section Electrical Characteristics page implied. Exposure absolute maximum rating conditions extended periods affect device reliability. Table Absolute Maximum Ratings Parameter SHDNN, VOUT Operating Temperature Range Storage Temperature Range -0.3 -0.3 -0.3 -0.3 +125 Units reflow peak soldering temperature (body temperature) specified accordance with IPC/JEDEC J-STD020C "Moisture/Reflow Sensitivity Classification Non-Hermetic Solid State Surface Mount Devices". lead finish Pb-free leaded packages matte (100% Sn). Notes
Package Body Temperature
+260
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AS1322 Data Sheet
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Descriptions
Electrical Characteristics
TAMB +1.2V, VOUT +3.3, VSHDNN +1.2V (unless otherwise specified). values TAMB Table Electrical Characteristics Symbol Parameter Minimum Start-Up Voltage Minimum Operating Voltage Output Voltage Adjust Range IQPWS IQSHDNN INMOSSWL IPMOSSWL RONNMOS Feedback Voltage Feedback Input Current Quiescent Current (Powersave Operation) Quiescent Current (Shutdown) Quiescent Current (Active) NMOS Switch Leakage PMOS Switch Leakage NMOS Switch Resistance Conditions ILOAD SHDNN TAMB TAMB TMIN TMAX 1.25V
0.85 0.66
0.85
Units
1.192 1.23 0.01 0.35 0.20 0.45 0.30
1.268
1.4V AS1322A only VSHDNN 1.4V AS1322B only VOUT 3.3V VOUT VOUT 3.3V VOUT 2.5V AS1322A only
RONPMOS INMOS
PMOS Switch Resistance NMOS Current Limit Powersave Operation Current Threshold Duty Cycle
0.95 0.85 0.35
TAMB TMIN TMAX TAMB TAMB TMIN TMAX
VSHDNNH VSHDNNL ISHDNN
Switching Frequency SHDNN Input High SHDNN Input SHDNN Input Current
VSHDNN 5.0V
0.01
Minimum operation after start-up only limited battery's ability provide necessary power enters deeply discharged state. Specification guaranteed design 100% production tested. IQPWS measured VOUT. Multiply this value VOUT/VIN equivalent input (battery) current.
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AS1322 Data Sheet
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Descriptions
Typical Operating Characteristics
Figure Powersave mode threshold VIN, VOUT 3.0V
Figure Efficiency Output Current, VOUT 3.3V
2.4V 1.5V
Output Current (mA)
0.75 1.25 1.75 2.25
Efficiency
1.0V
1000
Battery Voltage
Output Current (mA)
Figure Output Voltage Temperature; VOUT 3.3V, IOUT 10mA
3.36 3.34
Figure Output Voltage Battery Voltage; VOUT 3.3V, IOUT 10mA
Output Voltage
Output Voltage
3.32 3.28 3.26 3.24
Temperature (°C)
Battery Voltage
Figure Startup Voltage Output Current; VOUT 3.3V
Figure Output Current Battery Voltage; VOUT 3.3V, Tolerance
Startup Voltage
Output Current (mA)
Output Current (mA)
Battery Voltage
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AS1322 Data Sheet
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Descriptions
Figure Output Current Battery Voltage; VOUT 5.0V, Tolerance
Figure Load Battery Current VBATT VOUT 3.3V, TAMB
1000
Output Current (mA)
Battery Current (µA)
Battery Voltage
Battery Voltage
Figure Antiringing Operation 1.3V, VOUT 3.3V, 10µH, 10µF, IOUT
Figure Fixed Frequency Continuous Current 1.3V, VOUT 3.3V, 10µH, 10µF, IOUT 100mA
1V/Div
100ns/Div
100ns/Div
Figure VOUT Transient Response. 1.3V, VOUT 3.3V, 10µH, 10µF
Figure Fixed Frequency Powersave Operation 1.3V, VOUT 3.3V, 10µH, 10µF
100mV/Div
100mA
100µs/Div
40mA
10ms/Div
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IOUT
IOUT
60mA 100mV/Div
VOUT(AC)
VOUT(AC)
1V/Div
AS1322 Data Sheet
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Detailed Description
AS1322/AS1322B operate from single-cell input voltage (VIN) below feature fixed frequency (1.2MHz) current mode control exceptional line- load-regulation. With RDS(ON) gate charge internal NMOS PMOS switches, devices maintain high-efficiency from light heavy loads. Modern portable devices frequently spend extended time low-power standby modes, switching high powerdrain only when certain functions enabled. AS1322A AS1322B ideal portable devices since they maintain high-power conversion efficiency over wide output power range, thus increasing battery life these types devices. addition high-efficiency moderate heavy loads, AS1322A includes automatic powersave mode that improves efficiency power converter light loads. powersave mode initiated output load current falls below factory programmed threshold (see Figure page Note: AS1322B does support powersave mode provides continuous operation light loads, eliminating low-frequency VOUT ripple expense light load efficiency. Figure Block Diagram
4.7µH 1.5V Single Cell
Start
VOUT Good 2.3V VOUT 3.3V Output
Control Sync Drive Control 1.2MHz Ramp Generator Comp Shutdown Control Slope Compensator
0.35 Current Sense
0.45 CFF* 1.02M COUT 4.7µF
AS1322
Error
SHDNN
Shutdown
Powersave Operation Control
150pF
2.5pF
1.23V
Powersave
640k
Optional
Low-Voltage Start-Up
AS1322 requires only 0.85V (typ) higher start low-voltage start-up circuitry controls internal NMOS switch maximum peak inductor current 850mA (typ), with 1.5ms (approx.) off-time during start-up, allowing devices start into output load. With VOUT 2.3V, start-up circuitry disabled normal fixed-frequency operation initiated. this mode, AS1322 operates independent VIN, allowing extended operating time battery drop several tenths volt without affecting output regulation. limiting factor application ability battery supply sufficient energy output.
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AS1322 Data Sheet
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Low-Noise Fixed-Frequency Operation
Oscillator
AS1322 switching frequency internally fixed 1.2MHz allowing very small external components.
Error Amplifier
integrated error amplifier internally compensated trans-conductance (gm) type (current output). internal 1.23V reference voltage compared voltage generate error signal output error amplifier. voltage divider from VOUT programs output voltage from VOUT 1.23V(1 (R1/R2))
Current Sensing
signal representing internal NMOS-switch current summed with slope compensator. summed signal compared error amplifier output provide peak current control command PWM. Peak switch current limited approximately 850mA independent VOUT.
Zero Current Comparator
zero current comparator monitors inductor current output shuts PMOS synchronous rectifier once this current drops 20mA (approx.). This prevents inductor current from reversing polarity results improved converter efficiency light loads.
Anti-Ringing Control
Anti-ringing control circuitry prevents high-frequency ringing inductor current approaches zero. This accomplished damping resonant circuit formed inductor capacitance (CSW).
Powersave Operation (AS1322A)
light load conditions, integrated powersave feature removes power from circuitry required monitor VOUT. When VOUT dropped approximately from nominal, AS1322A powers begins normal operation. COUT (see Figure page recharges, causing AS1322A re-enter powersave mode long output load remains below powersave threshold. frequency this intermittent proportional load current; i.e., load current drops further below powersave threshold, AS1322A turns less frequently. When load current increases above powersave threshold, AS1322A will resume continuous, seamless operation. Notes: optional capacitor (CFF) between pins VOUT some applications reduce VOUTp-p ripple input quiescent current during powersave mode. Typical values range from 220pF. powersave mode AS1322A draws only 30µA from output capacitor(s), greatly improving converter efficiency.
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AS1322 Data Sheet
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Powersave Operation (AS1322A)
Application Information
AS1322 perfectly suited matrix displays, bar-graph displays, instrument-panel meters, matrix displays, set-top boxes, white goods, professional audio equipment, medical equipment, industrial controllers name applications. Along with Figure page Figures 16-19 depict many applications which AS1322 converters perfectly suited. Figure Single Cell 3.3V Synchronous Boost Converter with Load Disconnect Shutdown
4.7µH
VOUT
Battery
4.7µF
VOUT 3.3V, 150mA 510k 1.02M
AS1322
4.7µF
SHDNN
604k
510k
Figure Single Lithium Cell 250mA
Optional Snubber
100nF 4.7µH
VOUT
Lithium Battery
4.7µF
AS1322
4.7µF
1.02M
100pF
SHDNN
332k
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AS1322 Data Sheet
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Powersave Operation (AS1322A)
Figure Single Cell Synchronous Boost Converter
4.7µH
VOUT
Battery
4.7µF
VOUT1 90mA 1.02M 4.7µF
AS1322
SHDNN
750k
10µF VOUT2 -3V, 10mA
Figure Single Cell 2.5V Synchronous Boost Converter
10µH
VOUT
Battery
10µF
VOUT 2.5V, 230mA 1.02M 10µF
AS1322
SHDNN
1.02M
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AS1322 Data Sheet
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External Component Selection
External Component Selection
Inductor Selection
fast switching frequency (1.2MHz) AS1322 allows small surface mount chip inductor external inductor (see Figure page required minimum values external inductor are:
3.3µH applications 3.6V 4.7µH applications 3.6V
Larger inductor values allow greater output current capability reducing inductor ripple current. Increasing inductance above 10µH will increase size while providing negligible improvement output current capability. approximate output current capability AS1322 versus inductor value given IOUTMAX Where: estimated efficiency; peak current limit value (0.6A); input voltage; steady-state duty ratio (VOUT VIN)/VOUT; switching frequency (1.2MHz typ); inductor value. inductor current ripple typically maximum inductor current (IP). High-frequency ferrite core inductor materials reduce frequency dependent power losses compared less expensive powdered iron types, which result improved converter efficiency. inductor should have reduce power losses, must able handle peak inductor current without saturating. Molded chokes some chip inductors normally have enough core support peak inductor currents AS1322 (850mA typ). minimize radiated noise, toroid, core, shielded bobbin inductor.
(VIND))
((2fL)(1-D))
Output Capacitor Selection
capacitors should used minimize VOUT ripple. Multi-layer ceramic capacitors recommended since they have extremely available small footprints. 10µF output capacitor sufficient most applications. Larger values 22µF used obtain extremely output voltage ripple improve transient response. additional phase lead capacitor required with output capacitors larger than 10µF maintain acceptable phase margin. dielectric materials recommended their ability maintain capacitance over wide voltage temperature ranges.
Input Capacitor Selection
input capacitors reduce input switching noise reduce peak current drawn from battery. Ceramic capacitors recommended input decoupling should located close device practical. 4.7µF input capacitor sufficient most applications. Larger values used without limitations.
Diode Selection
Schottky diode should used carry output current time takes PMOS synchronous rectifier switch VOUT 4.5V Schottky diode optional, although using will increase device efficiency Note: ordinary rectifier diodes, since slow recovery times will compromise efficiency.
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AS1322 Data Sheet
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Layout Guidelines
high-speed operation AS1322 requires proper layout optimum performance. Figure shows recommended component layout.
large ground copper area will help lower device temperature. multi-layer board with separate ground plane recommended. Traces carrying large currents should direct. Trace area should small practical. lead-length battery should short practical.
Figure Recommended Single-Layer Component Placement
Optional
AS1322
VOUT SHDNN
SHDNN
COUT VOUT
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AS1322 Data Sheet
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Package Drawings Markings
device available 6-pin TSOT-23 package. Figure 6-pin TSOT-23 Package
Notes: Dimensioning tolerancing conform ASME Y14.5M 1994. Dimensions millimeters. Dimension does include mold flash, protrusions, gate burrs. Mold flash, protrusions, gate burrs shall exceed 0.15mm end. Dimension does include interlead flash protrusion. Interlead flash protrusion shall exceed 0.15mm side. Dimensions determined datum package smaller than package bottom. Dimensions determined outermost extremes plastic body exclusive mold flash, burrs, gate burrs, interlead flash, include mistmatches between package body bottom. determined datum Datums determined datum
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AS1322 Data Sheet
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These dimensions apply flat section lead between 0.08 0.15mm from lead tip. Dimension does include dambar protrusion. Allowable dambar protrusion shall 0.08mm total excess dimension maximum material condition. dambar cannot located lower radius foot. Minimum space between protrusion adjacent lead shall less than 0.77mm. Symbol 0.01 0.84 0.30 0.31 0.12 0.08 0.05 0.87 0.35 0.15 0.13 2.90BSC 2.80BSC 1.60BSC 0.95BSC 1.90BSC 0.40 0.60REF 0.25BSC 1.00 0.10 0.90 0.45 0.39 0.20 0.16 Notes
0.30
0.50
0.10 0.10
0.25
Tolerances Form Position 0.15 0.25 0.10 0.20
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AS1322 Data Sheet
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Ordering Information
device available standard products listed Table Table Ordering Information Model AS1322A-BTTT AS1322B-BTTT Marking ASKQ ASKZ Descriptiom Voltage, Micropower, DC-DC Step-Up Converter with Automatic Powersave Operation Voltage, Micropower, DC-DC Step-Up Converter with Continuous Switching Delivery Form Tape Reel Tape Reel Package 6-pin TSOT-23 6-pin TSOT-23
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AS1322 Data Sheet
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Layout Guidelines
Copyrights
Copyright 1997-2006, austriamicrosystems Schloss Premstaetten, 8141 Unterpremstaetten, Austria-Europe. Trademarks Registered rights reserved. material herein reproduced, adapted, merged, translated, stored, used without prior written consent copyright owner. products companies mentioned trademarks registered trademarks their respective companies.
Disclaimer
Devices sold austriamicrosystems covered warranty patent indemnification provisions appearing Term Sale. austriamicrosystems makes warranty, express, statutory, implied, description regarding information forth herein regarding freedom described devices from patent infringement. austriamicrosystems reserves right change specifications prices time without notice. Therefore, prior designing this product into system, necessary check with austriamicrosystems current information. This product intended normal commercial applications. Applications requiring extended temperature range, unusual environmental requirements, high reliability applications, such military, medical life-support lifesustaining equipment specifically recommended without additional processing austriamicrosystems each application. shipments less than parts manufacturing flow might show deviations from standard production flow, such test flow test location. information furnished here austriamicrosystems believed correct accurate. However, austriamicrosystems shall liable recipient third party damages, including limited personal injury, property damage, loss profits, loss use, interruption business indirect, special, incidental consequential damages, kind, connection with arising furnishing, performance technical data herein. obligation liability recipient third party shall arise flow austriamicrosystems rendering technical other services.
Contact Information
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Sales Offices, Distributors Representatives, please visit:
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