DESCRIPTIO from Single Li-Ion Cell 800mA SEPIC Mode from Four NiC

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DESCRIPTIO from Single Li-Ion Cell 800mA SEPIC Mode from Four NiC

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LT1308A/LT1308B High Current, Micropower Single Cell, 600kHz DC/DC Converters
DESCRIPTIO
from Single Li-Ion Cell 800mA SEPIC Mode from Four NiCd Cells Fixed Frequency Operation: 600kHz Boost Converter Outputs Starts into Heavy Loads Automatic Burst ModeOperation Light Load (LT1308A) Continuous Switching Light Loads (LT1308B) VCESAT Switch: 300mV Pin-for-Pin Upgrade Compatible with LT1308 Lower Quiescent Current Shutdown: (Max) Improved Accuracy Low-Battery Detector Reference: 200mV Available 8-Lead 14-Lead TSSOP Packages
®1308A/LT1308B micropower, fixed frequency step-up DC/DC converters that operate over input voltage range. They improved versions LT1308 recommended designs. LT1308A features automatic shifting power saving Burst Mode operation light loads consumes just 140A load. LT1308B features continuous switching light loads operates quiescent current 2.5mA. Both devices consume less than shutdown. Low-battery detector accuracy significantly tighter than LT1308. 200mV reference specified room over temperature. shutdown enables device when tied higher source does need tied LT1308. internal clamp results improved transient response switch voltage rating been increased 36V, enabling higher output voltage applications. LT1308A/LT1308B available 8-lead 14-lead TSSOP packages.
Lare registered trademarks Linear Technology Corporation. Burst Mode registered trademark Linear Technology Corporation. other trademarks property their respective owners.
APPLICATIO
GSM/CDMA Phones Digital Cameras Bias Supplies Answer-Back Pagers Receivers Battery Backup Supplies Handheld Computers
TYPICAL APPLICATIO
4.7H
Converter Efficiency
3.6V 4.2V
Li-Ion CELL
SHUTDOWN LT1308B SHDN 100pF
100k
EFFICIENCY
309k
1.5V
220F
TAJC476M010 TPSD227M006 10BQ015
MURATA LQH6C4R7 *R1: 887k VOUT
1308A/B F01a
LOAD CURRENT (mA) 1000
1308A/B F01b
Figure LT1308B Single Li-Ion Cell 5V/1A DC/DC Converter
2.5V
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LT1308A/LT1308B ABSOLUTE RATI (Note
Operating Temperature Range Commercial 70°C Extended Commerial (Note 40°C 85°C Industrial 40°C 85°C Storage Temperature Range 65°C 150°C Lead Temperature (Soldering, sec). 300°C VIN, SHDN, Voltage Voltage 0.4V Voltage Voltage Voltage 0.1V Current into ±1mA
FIGURATIO
VIEW SHDN
PACKAGE 8-LEAD PLASTIC TJMAX 125°C, 190°C/W
ORDER ATIO
LEAD FREE FINISH LT1308ACS8#PBF LT1308AIS8#PBF LT1308BCS8#PBF LT1308BIS8#PBF LT1308ACF#PBF LT1308BCF#PBF LEAD BASED FINISH LT1308ACS8 LT1308AIS8 LT1308BCS8 LT1308BIS8 LT1308ACF LT1308BCF TAPE REEL
LT1308ACS8#TRPBF LT1308AIS8#TRPBF LT1308BCS8#TRPBF LT1308BIS8#TRPBF LT1308ACF#TRPBF LT1308BCF#TRPBF TAPE REEL LT1308ACS8#TR LT1308AIS8#TR LT1308BCS8#TR LT1308BIS8#TR LT1308ACF#TR LT1308BCF#TR
Consult Marketing parts specified with wider operating temperature ranges. more information lead free part marking, http://www.linear.com/leadfree/ more information tape reel specifications,
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VIEW SHDN
PACKAGE 14-LEAD PLASTIC TSSOP (Note TJMAX 125°C, 80°C/W
RECOMMENDED DESIGNS
Contact Linear Technology Potential Replacement
PART MARKING 1308A 1308AI 1308B 1308BI LT1308ACF LT1308BCF PART MARKING 1308A 1308AI 1308B 1308BI LT1308ACF LT1308BCF
PACKAGE DESCRIPTION 8-Lead Plastic 8-Lead Plastic 8-Lead Plastic 8-Lead Plastic 14-Lead Plastic TSSOP 14-Lead Plastic TSSOP PACKAGE DESCRIPTION 8-Lead Plastic 8-Lead Plastic 8-Lead Plastic 8-Lead Plastic 14-Lead Plastic TSSOP 14-Lead Plastic TSSOP
TEMPERATURE RANGE 70°C -40°C 85°C 70°C -40°C 85°C 70°C 70°C TEMPERATURE RANGE 70°C -40°C 85°C 70°C -40°C 85°C 70°C 70°C
LT1308A/LT1308B
ELECTRICAL CHARACTERISTICS
SYMBOL PARAMETER Quiescent Current
denotes specifications which apply over full operating temperature range, otherwise specifications 25°C. Commercial Grade 70°C. 1.1V, VSHDN VIN, unless otherwise noted.
CONDITIONS Switching, LT1308A Switching, LT1308B VSHDN (LT1308A/LT1308B)
0.01
1.24
UNITS mhos
Feedback Voltage Bias Current Reference Line Regulation Minimum Input Voltage (Note 1.1V 1.2V Duty Cyle (Note (25°C, 0°C), 1.5V (70°C), 1.5V 2.5V, Circuit Figure VSHDN 1.1V VSHDN VSHDN
1.20
1.22 0.03 0.01 0.92
fOSC
Error Transconductance Error Voltage Gain Switching Frequency Maximum Duty Cycle Switch Current Limit Switch VCESAT Burst Mode Operation Switch Current Limit (LT1308A) Shutdown Current
0.01 0.01 3000
0.25
Threshold Voltage Output Leakage Current Input Bias Current (Note Low-Battery Detector Gain Switch Leakage Current
ISINK VLBI 250mV, VLBO VLBI 150mV
0.01
denotes specifications which apply over full operating temperature range, otherwise specifications 25°C. Industrial Grade 40°C 85°C. 1.2V, VSHDN VIN, unless otherwise noted.
SYMBOL PARAMETER Quiescent Current CONDITIONS Switching, LT1308A Switching, LT1308B VSHDN (LT1308A/LT1308B) (Note 1.1V
0.01
1.25
UNITS mhos
Feedback Voltage Bias Current Reference Line Regulation Minimum Input Voltage
1.19
1.22 0.05 0.01 0.92
Error Transconductance Error Voltage Gain
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LT1308A/LT1308B
ELECTRICAL CHARACTERISTICS
SYMBOL PARAMETER fOSC Switching Frequency Maximum Duty Cycle Switch Current Limit Switch VCESAT Burst Mode Operation Switch Current Limit (LT1308A) Shutdown Current
denotes specifications which apply over full operating temperature range, otherwise specifications 25°C. Industrial Grade 40°C 85°C. 1.2V, VSHDN VIN, unless otherwise noted.
CONDITIONS
UNITS
Duty Cyle (Note (25°C, 40°C), 1.5V (85°C), 1.5V 2.5V, Circuit Figure VSHDN 1.1V VSHDN VSHDN
0.01 0.01 3000
0.25
Threshold Voltage
Output Leakage Current Input Bias Current (Note Low-Battery Detector Gain Switch Leakage Current
ISINK VLBI 250mV, VLBO VLBI 150mV
0.01
Note Stresses beyond those listed under Absolute Maximum Ratings cause permanent damage device. Exposure Absolute Maximum Rating condition extended periods affect device reliability lifetime. Note LT1308ACS8, LT1308ACF, LT1308BCS8 LT1308BCF designed, characterized expected meet industrial temperature limits, tested 40°C 85°C. grade devices guaranteed over -40°C 85°C operating temperature range. Note Bias current flows into pin.
Note Switch current limit guaranteed design and/or correlation static tests. Duty cycle affects current limit ramp generator (see Block Diagram). Note Bias current flows pin. Note Connect four pins (Pins 4-7) together device. Similarly, connect three pins (Pins 8-10) together pins (Pins together device.
TYPICAL PERFORMANCE CHARACTERISTICS
LT1308B 3.3V Output Efficiency
EFFICIENCY
1.8V
2.5V
EFFICIENCY
1.2V
EFFICIENCY
LOAD CURRENT (mA)
1308A/B
LT1308A 3.3V Output Efficiency
1000 LOAD CURRENT (mA) 1000
1308A/B
LT1308A Output Efficiency
4.2V 3.6V
1.8V
2.5V
1.2V
1.5V
2.5V
LOAD CURRENT (mA)
1000
1308A/B
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LT1308A/LT1308B TYPICAL PERFORMANCE CHARACTERISTICS
LT1308B Output Efficiency
SWITCH VCESAT (mV)
CURRENT LIMIT
3.3V
EFFICIENCY
LOAD CURRENT (mA) 1000
1308A/B
SHDN Bias Current Voltage
SHDN CURRENT
BIAS CURRENT (nA)
25°C 85°C
VREF (mV)
SHDN VOLTAGE
1308
Oscillator Frequency Temperature
QUIESCENT CURRENT
FREQUENCY (kHz)
-2.5 TEMPERATURE (°C)
TEMPERATURE (°C)
1308
40°C
1308
Switch Current Limit Duty Cycle
Switch Saturation Voltage Current
85°C 25°C -40°C
DUTY CYCLE
1308
SWITCH CURRENT
1308
Bias Current Temperature
TEMPERATURE (°C)
1308
Battery Detector Reference Temperature
TEMPERATURE (°C)
1308
LT1308A Quiescent Current Temperature
Feedback Voltage Temperature
1.25 1.24 1.23 1.22 1.21 1.20 1.19 1.18
TEMPERATURE (°C)
1308
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LT1308A/LT1308B
FUNCTIONS
(Pin 1/Pin Compensation Error Amplifier. Connect series from this ground. Typical values 100pF. Minimize trace area (Pin 2/Pin Feedback Pin. Reference voltage 1.22V. Connect resistive divider here. Minimize trace area VOUT according VOUT 1.22V(1 R1/R2). SHDN (Pin 3/Pin Shutdown. Ground this turn switcher. enable, more. SHDN does need enable device. (Pin 4/Pins Ground. Connect directly local ground plane. Ground plane should enclose components associated with LT1308. copper connected these pins also functions heat sink. TSSOP package, connect pins ground copper best heat transfer. This keeps chip heating minimum.
(SO/TSSOP)
(Pin 5/Pins 10): Switch Pins. Connect inductor/ diode here. Minimize trace area these pins keep down. TSSOP package, connect pins together package. (Pin 6/Pins 12): Supply Pins. Must have local bypass capacitor right pins, connected directly ground. TSSOP package, connect both pins together package. (Pin 7/Pin 13): Low-Battery Detector Input. 200mV reference. Voltage must stay between -100mV Low-battery detector does function with SHDN grounded. Float used. (Pin 8/Pin 14): Low-Battery Detector Output. Open collector, sink 50A. 220k pull-up recommended. high impedance when SHDN grounded.
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LT1308A/LT1308B
BLOCK DIAGRA
2VBE SHDN
VOUT (EXTERNAL) (EXTERNAL)
140k
RAMP GENERATOR
600kHz OSCILLATOR *HYSTERESIS LT1308A ONLY
Figure LT1308A/LT1308B Block Diagram (SO-8 Package)
2VBE SHDN
ERROR AMPLIFIER BIAS
VOUT (EXTERNAL) (EXTERNAL)
140k RAMP GENERATOR
ENABLE 200mV
COMPARATOR DRIVER
600kHz OSCILLATOR *HYSTERESIS LT1308A ONLY
Figure LT1308A/LT1308B Block Diagram (TSSOP Package)
ERROR AMPLIFIER BIAS
SHUTDOWN
ENABLE 200mV
COMPARATOR
DRIVER
0.03
1308 BD2a
SHUTDOWN
0.03
1308 BD2b
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LT1308A/LT1308B
APPLICATIONS INFORMATION
OPERATION LT1308A combines current mode, fixed frequency architecture with Burst Mode micropower operation maintain high efficiency light loads. Operation best understood referring block diagram Figure form bandgap reference core whose loop closed around output converter. When feedback voltage 1.22V, along with 80mV drop across forward biases Q2's base collector junctions 300mV. Because this enough saturate either transistor, higher voltage than VIN. When there load, rises slightly above 1.22V, causing (the error amplifier's output) decrease. When reaches bias voltage hysteretic comparator A1's output goes low, turning circuitry except input stage, error amplifier lowbattery detector. Total current consumption this state 140A. output loading causes voltage decrease, A1's output goes high, enabling rest Switch current limited approximately 400mA initially after A1's output goes high. load light, output voltage (and voltage) will increase until A1's output goes low, turning rest LT1308A. frequency ripple voltage appears output. ripple frequency dependent load current output capacitance. This Burst Mode operation keeps output regulated reduces average current into resulting high efficiency even load currents less. output load increases sufficiently, A1's output remains high, resulting continuous operation. When LT1308A running continuously, peak switch current controlled regulate output voltage. switch turned beginning each switch cycle. When summation signal representing switch current ramp generator (introduced avoid subharmonic oscillations duty factors greater than 50%) exceeds signal, comparator changes state, resetting flip-flop turning switch. Output voltage increases switch current increased. output, attenuated resistor divider, appears pin, closing overall loop. Frequency compensation provided external series network connected between ground. Low-battery detector A4's open-collector output (LBO) pulls when voltage drops below 200mV. There hysteresis allowing used amplifier some applications. entire device disabled when SHDN brought low. enable converter, SHDN must greater. need tied LT1308. LT1308B differs from LT1308A that there hysteresis comparator Also, bias point lower than LT1308B that switching occur inductor current less than 100mA. Because hysteresis, there Burst Mode operation light loads device continues switching constant frequency. This results absence frequency output voltage ripple expense efficiency. difference between devices clearly illustrated Figure traces Figure shows LT1308A/LT1308B circuit, using components indicated Figure output. Input voltage Load current stepped from 50mA 800mA both circuits. frequency Burst Mode operation voltage ripple observed Trace while none observed Trace light loads, LT1308B will begin skip alternate cycles. load point which this occurs decreased increasing inductor value. However, output ripple will continue significantly less than LT1308A output ripple. Further, LT1308B forced into micropower mode, where falls from 200A sinking more pin. This stops switching causing A1's output low.
TRACE LT1308A VOUT, 100mV/DIV COUPLED TRACE LT1308B VOUT, 100mV/DIV COUPLED 800mA ILOAD 50mA 200s/DIV (CIRCUIT FIGURE
1308
Figure LT1308A Exhibits Burst Mode Operation Output Voltage Ripple 50mA Load, LT1308B Does
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LT1308A/LT1308B
APPLICATIONS INFORMATION
Waveforms LT1308B boost converter using ceramic output capacitor pictured Figures Figure converter operating continuous mode, delivering load current approximately 500mA. trace output. voltage increases inductor current dumped into output capacitor during switch time, voltage decreases when switch Ripple voltage this case capacitance, ceramic capacitor little ESR. middle trace switch voltage. This voltage alternates between VCESAT VOUT plus diode drop. lower trace switch current. beginning switch cycle, current 1.2A. switch time, current increased which point switch turns inductor current flows into output capacitor through diode. Figure depicts converter waveforms light load. Here converter operates discontinuous mode. inductor current reaches zero during switch time, resulting some ringing switch node. ring frequency switch capacitance, diode capacitance inductance. This ringing little energy, sinusoidal shape suggests free from harmonics. Minimizing copper area switch node will prevent this from causing interference problems.
VOUT 100mV/DIV 10V/DIV MULTIPLE VIAs 1A/DIV 500ns/DIV VOUT
Figure Boost Converter Waveforms Continuous Mode. Ceramic Capacitor Used Output
VOUT 20mV/DIV
10V/DIV 500mA/DIV 500ns/DIV
Figure Converter Waveforms Discontinuous Mode
LAYOUT HINTS LT1308A/LT1308B switch current high speed, mandating careful attention layout proper performance. will advertised performance with careless layout. Figure shows recommended component placement SO-8 package boost (step-up) converter. Follow this closely your layout. Note direct path switching loops. Input capacitor must placed close 5mm) package. little 10mm wire trace from will cause problems such inability regulate oscillation. negative terminal output capacitor should close ground pin(s) LT1308A/LT1308B. Doing this reduces dI/dt ground copper which keeps high frequency spikes minimum. DC/DC converter ground should board ground plane place only, avoid introducing dI/dt ground plane.
GROUND PLANE
SHUTDOWN
LT1308A LT1308B
1308
Figure Recommended Component Placement SO-8 Package Boost Converter. Note Direct High Current Paths Using Wide Traces. Minimize Trace Area (VC) (FB). Multiple Vias Copper Ground Plane. Vias Location Only Avoid Introducing Switching Currents into Ground Plane
Figure shows recommended component placement boost converter using TSSOP package. Placement similar SO-8 package layout.
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LT1308A/LT1308B
APPLICATIONS INFORMATION
GROUND PLANE
SHUTDOWN
LT1308A LT1308B
MULTIPLE VIAs
VOUT
Figure Recommended Component Placement TSSOP Boost Converter. Placement Similar Figure
GROUND PLANE
SHUTDOWN
LT1308A LT1308B
MULTIPLE VIAs
Figure Recommended Component Placement SEPIC
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SEPIC (Single-Ended Primary Inductance Converter) schematic shown Figure This converter topology produces regulated output over input voltage range that spans (i.e., higher lower than) output. Recommended component placement SO-8 package SEPIC shown Figure
CTX10-2 4.7F CERAMIC
SHUTDOWN LT1308B SHDN 680pF
309k 100k VOUT 500mA
220F 6.3V
TAJC476M016 TAIYO YUDEN EMK325BJ475(X5R) TPSD227M006
1308
10BQ015 COILTRONICS CTX10-2
1308A/B
Figure SEPIC (Single-Ended Primary Inductance Converter) Converts Input 5V/500mA Regulated Output
VOUT
1308
LT1308A/LT1308B
APPLICATIONS INFORMATION
SHDN LT1308A/LT1308B SHDN improved over LT1308. does require tying enable device, needs only logic level signal. voltage SHDN vary from independent VIN. Further, floating this same effect grounding, which shut device down, reducing current drain less. LOW-BATTERY DETECTOR low-battery detector LT1308A/LT1308B features improved accuracy drive capability compared LT1308. 200mV reference accuracy open-collector output sink 50A. LT1308A/ LT1308B low-battery detector simple input gain stage with open-collector output. negative input gain stage tied internally 200mV reference. positive input pin. Arrangement low-battery detector straightforward. Figure details hookup. need only enough value that bias current doesn't cause large errors. 100k adequate. 200mV reference also accessed shown Figure
100k LT1308A LT1308B
VLBI (mV)
1308
200mV INTERNAL REFERENCE
100k PROCESSOR
VBAT
200mV
1308
Figure Setting Low-Battery Detector Trip Point
200k 2N3906 VBAT VREF 200mV
LT1308A LT1308B
1308
Figure Accessing 200mV Reference
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cross plot low-battery detector shown Figure swept with input which varies from 195mV 205mV, (with 100k pull-up resistor) displayed.
VLBO 1V/DIV
Figure Low-Battery Detector Input/Output Characteristic
START-UP LT1308A/LT1308B start into heavy loads, unlike many CMOS DC/DC converters that derive operating voltage from output technique known "bootstrapping"). Figure details start-up waveforms Figure circuit with load 1.5V. Inductor current rises 3.5A output capacitor charged. After output reaches inductor current about Figure load input voltage Output voltage reaches 500s after device enabled. Figure shows start-up behavior Figure SEPIC circuit, driven from input with load. output reaches about after device enabled.
VOUT 2V/DIV
1A/DIV VSHDN 5V/DIV 1ms/DIV
1308
Figure Boost Converter Figure Start-Up from 1.5V Input into Load
LT1308A/LT1308B
APPLICATIONS INFORMATION
VOUT 1V/DIV
2A/DIV VSHDN 5V/DIV 500s/DIV
1308
Figure Boost Converter Figure Start-Up from Input into Load
VOUT 2V/DIV
2A/DIV VSHDN 5V/DIV 500s/DIV
1308
Figure SEPIC Start-Up from Input into Load
Soft-Start some cases undesirable LT1308A/ LT1308B operate current limit during start-up, e.g.,
SHUTDOWN
33nF 11.3k 100pF
SOFT-START COMPONENTS TAJ476M010 TAIYO YUDEN TMK432BJ106MM 10BQ015 MURATA LQH6C4R7 2N3904
Figure Boost Converter with Soft-Start Components
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when operating from battery composed alkaline cells. inrush current cause sufficiency internal voltage drop trigger low-battery indicator. programmable soft-start implemented with discrete components. boost converter using LT1308B detailed Figure differentiates VOUT, causing current flow into VOUT increases. When this current exceeds 0.7V/33k, 21A, current flows into base Q1's collector then pulls current pin, creating feedback loop where slope VOUT limited follows: VOUT 0.7V With 33nF, VOUT/t limited 640mV/ms. Start-up waveforms Figure 16's circuit pictured Figure Without soft-start circuit implemented, inrush current reaches circuit reaches final output voltage approximately 250s. Adding soft-start components reduces inductor current less than detailed Figure while time required reach final output voltage increases about 15ms. adjusted achieve output slew rate desired.
4.7H
VOUT 500mA
SHDN LT1308B
100k
330pF
1308
LT1308A/LT1308B
APPLICATIONS INFORMATION
VOUT 5V/DIV
1A/DIV VSHDN 10V/DIV 50s/DIV
1308
Figure Start-Up Waveforms Figure 16's Circuit without Soft-Start Components
VOUT
1A/DIV VSHDN 10V/DIV 5ms/DIV
1308
Figure Start-Up Waveforms Figure 16's Circuit with Soft-Start Components Added
COMPONENT SELECTION Diodes have found Semiconductor MBRS130 International Rectifier 10BQ015 perform well. applications where VOUT exceeds 30V, diodes such MBRS140 10BQ040. Height limited applications benefit from MBRM120. This component only tall offers performance similar MBRS130. Inductors Suitable inductors with LT1308A/LT1308B must fulfill requirements. First, inductor must able handle current steady-state, well support transient start-up current over without inductance decreasing more than 60%. Second, inductor should have DCR, under 0.05
that copper loss minimized. Acceptable inductance values range between 20H, with 4.7H best most applications. Lower value inductors physically smaller than higher value inductors same current capability. Table lists some inductors have found perform well LT1308A/LT1308B application circuits. This exclusive list.
Table
VENDOR Murata Sumida Coiltronics Coilcraft PART LQH6C4R7 CDRH734R7 CTX5-1 LPO2506IB-472 VALUE 4.7H 4.7H 4.7H PHONE 770-436-1300 847-956-0666 561-241-7876 847-639-6400
Capacitors Equivalent Series Resistance (ESR) main issue regarding selection capacitors, especially output capacitors. output capacitors specified with LT1308A/ LT1308B circuits have specifically designed power supply applications. Output voltage ripple boost converter equal multiplied switch current. performance TPSD227M006 220F tantalum evaluated referring Figure When load 800mA, peak switch current approximately Output voltage ripple about 60mVPP, output capacitor 60mV/2A 0.03. Ripple further reduced paralleling ceramic units. Table lists some capacitors have found perform well LT1308A/LT1308B application circuits. This exclusive list.
Table
VENDOR Taiyo Yuden Taiyo Yuden SERIES PART TPSD227M006 TPSD107M010 LMK432BJ226 TMK432BJ106 VALUE 220F, PHONE 803-448-9411
100F, 803-448-9411 22F, 10F, 408-573-4150 408-573-4150
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LT1308A/LT1308B
APPLICATIONS INFORMATION
Ceramic Capacitors Multilayer ceramic capacitors have become popular, their small size, cost, near-zero ESR. Ceramic capacitors used successfully LT1308A/LT1308B designs provided loop stability considered. tantalum capacitor some this causes "ESR zero" regulator loop. This zero beneficial loop stability. Ceramics have appreciable ESR, zero lost when they used. However, LT1308A/LT1308B have external compensation (VC) component values adjusted achieve stability. phase lead capacitor also used tune load step response optimum levels, detailed following paragraphs. Figure details boost converter using either tantalum ceramic capacitor input capacitor little effect loop stability, long minimum capacitance requirements met. phase lead capacitor parallels feedback resistor Figure shows load step response 50mA 500mA load step using tantalum capacitor output. Without phase lead capacitor, there some ringing, suggesting phase margin low. then added, response same load step pictured Figure Some phase margin restored, improving response. Next, replaced 10F, dielectric, ceramic capacitor.
4.7H VOUT 500mA
SHDN LT1308B
330pF
100k
100pF
11.3k
TAJC476M010 TPSD476M016 (47F) TAIYO YUDEN TMK432BJ106MM (10F) 10BQ015 MURATA LQH6C4R7
1308
Figure Boost Converter
Without CPL, load step response pictured Figure Although output settles faster than tantalum case, there appreciable ringing, again suggesting phase margin low. Figure depicts load step response using ceramic output capacitor CPL. Response clean ringing evident. Ceramic capacitors have added benefit lowering ripple switching frequency their very ESR. applying tandem with series pin, loop response tailored optimize response using ceramic output capacitors.
VOUT 500mV/DIV
1A/DIV LOAD CURRENT 500mA 50mA 200s/DIV
1308
Figure Load Step Response LT1308B Boost Converter with Tantalum Output Capacitor
VOUT 500mV/DIV
1A/DIV LOAD CURRENT 500mA 50mA 200s/DIV
1308
Figure Load Step Response with Tantalum Output Capacitor Phase Lead Capacitor
VOUT 1V/DIV
1A/DIV LOAD CURRENT 500mA 50mA 200s/DIV
1308
Figure Load Step Response with Ceramic Output Capacitor
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LT1308A/LT1308B
APPLICATIONS INFORMATION
VOUT 500mV/DIV VOUT 4.2V VOUT 3.6V 1A/DIV LOAD CURRENT 500mA 50mA 200s/DIV
1308
Figure Load Step Response with Ceramic Output Capacitor
CDMA PHONES LT1308A/LT1308B suitable converting single Li-Ion cell powering power stages CDMA phones. Improvements LT1308A/LT1308B error amplifiers allow external compensation values reduced, resulting faster transient response compared LT1308. circuit Figure (same Figure printed again convenience) provides output from Li-Ion cell. Figure details transient response LT1308A operating 4.2V, 3.6V Ripple voltage Burst Mode operation seen 10mA load. Figure shows transient response LT1308B under same conditions. Note lack Burst Mode ripple 10mA load.
4.7H LT1308B SHDN 100pF TAJC476M010 TPSD227M006 10BQ015 MURATA LQH6N4R7 100k 309k
VOUT 4.2V VOUT 3.6V VOUT ILOAD 10mA
Li-Ion CELL
SHUTDOWN
Figure Li-Ion Boost Converter Delivers
VOUT ILOAD 10mA VOUT TRACES 200mV/DIV 200s/DIV
1308
Figure LT1308A Li-Ion Boost Converter Transient Response Load Step
VOUT TRACES 200mV/DIV
100s/DIV
1308
Figure LT1308B Li-Ion Boost Converter Transient Response Load Step
220F
1308A/B
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LT1308A/LT1308B
TYPICAL APPLICATIO
Triple Output TFTLCD Bias Supply
0.22F 0.22F VOFF 10mA 0.22F 15mA
4.7F 220k 100pF
C1:TAIYO-YUDEN JMK212BJ475MG C3:TAIYO-YUDEN LMK325BJ106MN C6:TAIYO-YUDEN EMK212BJ105MG MBRM120 D2,D3,D4: BAT54S TOKO 817FY-4R7M
ILOAD
4.7H SHDN LT1308B
AVDD 500mA 76.8k
10.7k
1308 TA02
TFTLCD Bias Supply Transient Response
AVDD 500mV/DIV
500mV/DIV VOFF 500mV/DIV 800mA 200mA 100s/DIV
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LT1308A/LT1308B
TYPICAL APPLICATIO
40nF Panel Driver
1:12
3.3V REGULATED 100k 150k
3.3k
TAJC476M010 VITRAMON VJ225Y105KXCAT BAT54 BAV21
High Voltage Supply 350V 1.2mA
10nF 250V 10nF 250V VOUT 350V 1.2mA
2.7V
1:12
10nF 250V
SHUTDOWN SHDN LT1308A
100pF 10nF BAV21 200mA, 250V MBR0540 MIDCOM 31105R 1.5H
34.8k
VBAT
324k 22nF 49.9k 100pF 47pF SHDN SHUTDOWN 400V LT1308A 200V PANEL 40nF 4.3M
1308 TA03
MMBT3906 ZETEX FCX458 MIDCOM 31105
SEPIC Converts Input 5V/500mA Regulated Output
CTX10-2
4.7F CERAMIC
SHUTDOWN LT1308B SHDN
309k 100k VOUT 500mA
680pF TAJC476M016 TAIYO YUDEN EMK325BJ475(X5R) TPSD227M006
1308 TA04
220F 6.3V
10BQ015 COILTRONICS CTX10-2
1308A/B TA05
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LT1308A/LT1308B
PACKAGE DESCRIPTION
Package 8-Lead Plastic Small Outline (Narrow .150 Inch)
(Reference 05-08-1610)
.189 .197 (4.801 5.004) NOTE
.050
.245
.030 ±.005 RECOMMENDED SOLDER LAYOUT
.010 .020 (0.254 0.508) .008 .010 (0.203 0.254)
.016 .050 (0.406 1.270) NOTE: DIMENSIONS
INCHES (MILLIMETERS) DRAWING SCALE THESE DIMENSIONS INCLUDE MOLD FLASH PROTRUSIONS. MOLD FLASH PROTRUSIONS SHALL EXCEED .006" (0.15mm)
.045 ±.005
.160 ±.005
.228 .244 (5.791 6.197)
.150 .157 (3.810 3.988) NOTE
.053 .069 (1.346 1.752)
.004 .010 (0.101 0.254)
.014 .019 (0.355 0.483)
.050 (1.270)
0303
1308abfa
LT1308A/LT1308B
PACKAGE DESCRIPTION
Package 14-Lead Plastic TSSOP (4.4mm)
(Reference 05-08-1650)
4.90 5.10* (.193 .201) 1.05 ±0.10
6.60 ±0.10
0.45 0.05
RECOMMENDED SOLDER LAYOUT 4.30 4.50** (.169 .177)
0.09 0.20 (.0035 .0079)
0.50 0.75 (.020 .030)
NOTE: CONTROLLING DIMENSION: MILLIMETERS MILLIMETERS DIMENSIONS (INCHES)
DRAWING SCALE *DIMENSIONS INCLUDE MOLD FLASH. MOLD FLASH SHALL EXCEED .152mm (.006") SIDE **DIMENSIONS INCLUDE INTERLEAD FLASH. INTERLEAD FLASH SHALL EXCEED .254mm (.010") SIDE
Information furnished Linear Technology Corporation believed accurate reliable. However, responsibility assumed use. Linear Technology Corporation makes representation that interconnection circuits described herein will infringe existing patent rights.
4.50 ±0.10
6.40 (.252)
0.65 1.10 (.0433)
0.25
0.65 (.0256) 0.19 0.30 (.0075 .0118)
0.05 0.15 (.002 .006)
TSSOP 0204
1308abfa
LT1308A/LT1308B
TYPICAL APPLICATIO
2.7V 4.2V SHUTDOWN
TAJC476M010 TPSD107M016 10BQ015
RELATED PARTS
PART NUMBER LT1302 LT1304 LT1316 LTC®1474 LTC1516 LTC1522 LT1610 LT1611 LT1613 LT1615 LT1617 LTC1682 LT1949 LT1949-1 DESCRIPTION High Output Current Micropower DC/DC Converter 2-Cell Micropower DC/DC Converter Burst Mode Operation DC/DC with Programmable Current Limit Micropower Step-Down DC/DC Converter 2-Cell Regulated Charge Pump Micropower, Charge Pump DC/DC Converter Single-Cell Micropower DC/DC Converter Inverting 1.4MHz Switching Regulator 5-Lead SOT-23 1.4MHz Switching Regulator 5-Lead SOT-23 Micropower Step-Up DC/DC 5-Lead SOT-23 Micropower Inverting DC/DC Converter SOT-23 Doubler Charge Pump with Noise 600kHz, Switch DC/DC Converter 1.1MHz, Switch DC/DC Converter COMMENTS 5V/600mA from Internal Switch, 200A 5V/200mA, Low-Battery Detector Active Shutdown 3.3V 75mA from Cell, MSOP Package 1.5V Minimum, Precise Control Peak Current Limit 100A Operate with 1.5V Efficiency, 250mA Inudctors, 50mA from Input Regulated Output, 20mA from Input 30mA from 1.7MHz Fixed Frequency 150mA from Input, Tiny SOT-23 package 200mA from 4.4V Input, Tiny SOT-23 package 36V, 350mA Switch 15V; VOUT -34V Adjustable Fixed 3.3V, Outputs, 60VRMS Output Noise 1.1A, 0.5, Internal Switch, 1.5V 1.1MHz Version LT1949
LT1307/LT1307B Single Cell, Micropower, 600kHz DC/DC Converters LT1317/LT1317B Micropower, 600kHz DC/DC Converters
Linear Technology Corporation
1630 McCarthy Blvd., Milpitas, 95035-7417
(408)432-1900 FAX: (408) 434-0507 www.linear-tech.com
Li-Ion 12V/300mA Step-Up DC/DC Converter
4.7H 300mA LT1308B SHDN 330pF MURATA LQH6C4R7
1308A/B TA01
Li-Ion CELL
887k 100k
100F
1308abfa 0807 PRINTED
LINEAR TECHNOLOGY CORPORATION 1999

DESCRIPTIO from Single Li-Ion Cell 800mA SEPIC Mode from Four NiC

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