LT®3460/LT3460-1 general purpose step-up converters. LT3460/LT3460-1 s

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LT®3460/LT3460-1 general purpose step-up converters. LT3460/LT3460-1 s

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LT3460/LT3460-1 MHz/650kHz Step-Up DC/DC Converter SC70, ThinSOT DESCRIPTION
LT®3460/LT3460-1 general purpose step-up converters. LT3460/LT3460-1 switch 1.3MHz/ 650kHz, allowing tiny, cost height capacitors inductors. constant frequency results low, predictable output noise that easy filter. high voltage switches LT3460/LT3460-1 rated 38V, making device ideal boost converters 36V. LT3460 generate 70mA from supply. quiescent current 650kHz switching frequency LT3460-1 make ideal lower current applications. LT3460 available SC70 SOT-23 packages. LT3460-1 available SC70 packages.
Lare registered trademarks Linear Technology Corporation. ThinSOT trademark Linear Technology Corporation. other trademarks property their respective owners.
1.3MHz (LT3460) Switching Frequency 650kHz (LT3460-1) Switching Frequency High Output Voltage: 300mA Integrated Switch (LT3460) 180mA Integrated Switch (LT3460-1) Wide Input Range: 2.5V Uses Small Surface Mount Components Shutdown Current: Profile (1mm) SC70 (LT3460 LT3460-1), SOT-23 (ThinSOTTM) (LT3460) (LT3460-1) Packages
APPLICATIONS
Digital Cameras Bias Supply XDSL Power Supply TFT-LCD Bias Supply Local Supply Medical Diagnostic Equipment Battery Backup
TYPICAL APPLICATION
EFFICIENCY
Efficiency
12V, 70mA Step-Up DC/DC Converter
4.7F LT3460 SHDN VOUT 70mA 130k 22pF
LOAD CURRENT (mA)
3460 F01a
Switching Waveforms
3460
5V/DIV
100mA/DIV
0.2s/DIV
3460 F01b
3460fb
LT3460/LT3460-1 ABSOLUTE MAXIMUM RATINGS
Input Voltage (VIN) .16V Voltage .38V Voltage SHDN Voltage .16V
(Note
Operating Ambient Temperature Range (Note 40°C 85°C Maximum Junction Temperature. 125°C Storage Temperature Range. -65°C 150°C Lead Temperature (Soldering, sec) 300°C
CONFIGURATION
VIEW SHDN VIEW SHDN
PACKAGE 5-LEAD PLASTIC TSOT-23 TJMAX 125°C, 256°C/W FREE 120°C BOARD OVER GROUND PLANE VIEW SHDN
PACKAGE 6-LEAD PLASTIC SC70 TJMAX 125°C, 400°C/W FREE 270°C/W BOARD OVER GROUND PLANE
PACKAGE 6-LEAD (2mm 2mm) PLASTIC TJMAX 125°C, 102°C/W EXPOSED (PIN GND, MUST SOLDERED
ORDER INFORMATION
LEAD FREE FINISH LT3460ES5#PBF LT3460ESC6#PBF LT3460ESC6-1#PBF LT3460EDC-1#PBF TAPE REEL LT3460ES5#TRPBF LT3460ESC6#TRPBF LT3460ESC6-1#TRPBF LT3460EDC-1#TRPBF PART MARKING LTB1 LAAF LDJV LDNB PACKAGE DESCRIPTION 5-Lead Plastic TSOT-23 6-Lead Plastic SC70 6-Lead Plastic SC70 6-Lead (2mm 2mm) Plastic TEMPERATURE RANGE -40°C 85°C -40°C 85°C -40°C 85°C -40°C 85°C
Consult Marketing parts specified with wider operating temperature ranges. Consult Marketing information non-standard lead based finish parts. more information lead free part marking, http://www.linear.com/leadfree/ more information tape reel specifications,
3460fb
LT3460/LT3460-1 ELECTRICAL CHARACTERISTICS
PARAMETER Minimum Operating Voltage Maximum Operating Voltage Feedback Voltage Feedback Line Regulation Bias Current Supply Current Switching Frequency Maximum Duty Cycle Switch Current Limit Switch VCESAT Switch Leakage Current SHDN Voltage High SHDN Voltage SHDN Bias Current Note Stresses beyond those listed under Absolute Maximum Ratings cause permanent damage device. Exposure Absolute Maximum Rating condition extended periods affect device reliability lifetime. 250mA (LT3460), 100mA (LT3460-1) SHDN 2.5V
denotes specifications which apply over full operating temperature range, otherwise specifications 25°C, VSHDN unless otherwise noted. LT3460 LT3460-1
CONDITIONS 1.235 1.225 1.255 0.015 0.01 0.35 1.275 1.280 1.235 1.225 1.255 0.015 0.65 0.01 1.275 1.280 UNITS
Note LT3460E/LT3460-1E guaranteed meet specifications from 70°C. Specifications over -40°C 85°C operating temperature range assured design, characterization correlation with statistical process controls.
TYPICAL PERFORMANCE CHARACTERISTICS
Quiescent Current
-50°C 100°C (mA) LT3460-1 LT3460 SWITCHING FREQUENCY (MHz) SHDN BIAS CURRENT
3460
Switching Frequency
LT3460
SHDN Bias Current
SHDN (LT3460)
25°C
LT3460-1
SHDN (LT3460-1) SHDN (LT3460-1) SHDN (LT3460) TEMPERATURE (°C)
3460
TEMPERATURE (°C)
3460
3460fb
LT3460/LT3460-1 TYPICAL PERFORMANCE CHARACTERISTICS
Feedback Bias Current
FEEDBACK BIAS CURRENT (nA) 1.255 1.245 1.240 1.250 1.260
Feedback Voltage
TEMPERATURE (°C)
3460
TEMPERATURE (°C)
3460
Switch Saturation Voltage (VCESAT)
VCESAT (mV) TEMPERATURE (°C)
3460
Current Limit Duty Cycle
CURRENT LIMIT (mA) LT3460
250mA 200mA
(LT3460) (LT3460)
DUTY CYCLE
50mA
(LT3460-1) (LT3460)
100mA
LT3460-1
3460
FUNCTIONS (ThinSOT/SC70/DFN Packages)
(Pin 1/Pin 1/Pin Switch Pin. Connect inductor/diode here. Minimize trace this reduce EMI. (Pin 2/Pins 5/Exposed Ground Pin. directly local ground plane. (Pin 3/Pin 3/Pin Feedback Pin. Reference voltage 1.255V. Connect resistor divider here. Minimize trace area VOUT according VOUT 1.255V R1/R2). SHDN (Pin 4/Pin 4/Pin Shutdown Pin. 1.5V higher enable device; 0.4V less disable device. Also functions soft-start. filter (47k, 47nF typ) shown Figure (Pin 5/Pin 6/Pin Input Supply Pin. Must locally bypassed. (NA/NA/Pins No-Connects. These pins connected internal circuitry. They should tied ground improve thermal electrical performance.
3460fb
LT3460/LT3460-1 BLOCK DIAGRAM
VOUT (EXTERNAL) (EXTERNAL) 1.255V REFERENCE
COMPARATOR
DRIVER
SHUTDOWN (EXTERNAL) SHDN (EXTERNAL) OPTIONAL SOFT-START COMPONENTS 1.3MHz OSCILLATOR
3460
RAMP GENERATOR
Figure Block Diagram, LT3460
OPERATION
LT3460/LT3460-1 uses constant frequency, current mode control scheme provide excellent line load regulation. Operation best understood referring block diagram Figure start each oscillator cycle, latch set, which turns power switch voltage proportional switch current added stabilizing ramp resulting into positive terminal comparator When this voltage exceeds level negative input latch reset turning power switch. level negative input error amplifier simply amplified version difference between feedback voltage reference voltage 1.255V. this manner, error amplifier sets correct peak current level keep output regulation. error amplifier's output increases, more current delivered output; decreases, less current delivered. Feedback Loop Compensation LT3460/LT3460-1 internal feedback compensation network shown Figure CC). However, because small signal characteristics boost converter change with operation conditions, internal compensation network cannot satisfy applications. properly designed external feed forward capacitor from VOUT Figure will correct loop compensation most applications. LT3460/LT3460-1 uses peak current mode control. current feedback makes inductor very similar current source medium frequency range. power stage transfer function medium frequency range approximated GP(s)
where output capacitance, constant based operating point converter. continuous current mode, increases duty cycle decreases. internal compensation network approximated follows medium frequency range: GC(s) zero
about 70kHz.
3460fb
LT3460/LT3460-1 OPERATION
4.7F LT3460 SHDN TAIYO YUDEN JMK212BJ475KG TAIYO YUDEN EMK316BJ105 CENTRAL SEMICONDUCTOR CMDSH2-3 MURATA LQH32CN-220 EQUIVALENT 130k
VOUT 70mA
GAIN PHASE (DEG) PHASE -135 -180 -225 -270 -315 FREQUENCY (kHz) -360 1000
3460
GAIN (dB)
22pF
3460
Figure Step-Up Converter
GAIN (dB)
feedback loop gain T(s) GP(s) GC(s). crosses over before phase margin will small. Figure Bode plot feedback loop gain measured from converter shown Figure without feedforward capacitor result agrees with previous discussion: Phase margin about insufficient. order improve phase margin, feed-forward capacitor Figure used. Without feed-forward capacitor, transfer function from VOUT VOUT With feed-forward capacitor transfer function becomes: VOUT
Figure
FREQUENCY (kHz) PHASE GAIN PHASE (DEG) -135 -180 -225 -270 -315 -360 1000
3460
Figure
feed-forward capacitor increases gain high frequency. feedback loop therefore needs have enough attenuation switching frequency reject switching noise. Additional internal compensation components have taken this into consideration. most applications LT3460/LT3460-1, output capacitor zero very high frequency ignored. frequency zero exists, example, when high-ESR Tantalum capacitor used output, phase margin enough even without feed-forward capacitor. these cases, feed-forward capacitor should added because cause feedback loop have enough attenuation switching frequency.
feed-forward capacitor generates zero pole. zero always appears before pole. frequency distance between zero pole determined only ratio between VOUT give maximum phase margin, should chosen that midpoint frequency between zero pole cross over frequency. With 20pF feedback loop Bode plot reshaped shown Figure phase margin about 60°.
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LT3460/LT3460-1 OPERATION
Layout Hints high speed operation LT3460/LT3460-1 demands careful attention board layout. will advertised performance with careless layout. Figure shows recommended component placement.
VOUT
VOUT SHUTDOWN
(SC70 PACKAGE)
3460 F05b
SHUTDOWN
SHDN
(SOT-23 PACKAGE)
3460 F05a
VOUT
(6-LEAD PACKAGE)
3460 F05c
Figure
TYPICAL APPLICATIONS
Step-Up Converter
4.7F SHDN LT3460 SHDN TAIYO YUDEN JMK212BJ475 TAIYO YUDEN EMK212BJ105 CENTRAL SEMICONDUCTOR CMDSH2-3 MURATA LQH32CN-220 EQUIVALENT 130k 22pF VOUT 70mA EFFICIENCY
3460 TA01
Efficiency
LOAD CURRENT (mA)
3460 TA01a
3460fb
LT3460/LT3460-1 TYPICAL APPLICATIONS
Load Step Response
VOUT 100mV/DIV
ILOAD
58mA 34mA
100s/DIV
3460 TA01b
with Soft-Start Circuit
4.7F CONTROL SIGNAL SHDN 47nF LT3460 130k 22pF VOUT 70mA
Input Current Output Voltage
100mA/DIV
5V/DIV CONTROL SIGNAL 2V/DIV
TAIYO YUDEN JMK212BJ475 TAIYO YUDEN EMK212BJ105 CENTRAL SEMICONDUCTOR CMDSH2-3 MURATA LQH32CN-220 EQUIVALENT
3460 TA02
500s/DIV
3460 TA02b
Step-Up Converter
3.3V 4.7F VOUT 40mA 130k 22pF TAIYO YUDEN JMK212BJ475 TAIYO YUDEN EMK212BJ105 CENTRAL SEMICONDUCTOR CMDSH2-3 MURATA LQH32CN-220 EQUIVALENT
3460 TA03
Efficiency
EFFICIENCY
LT3460 SHDN
LOAD CURRENT (mA)
3460 TA03a
3460fb
LT3460/LT3460-1 TYPICAL APPLICATIONS
Step-Up Converter
2.7V 4.2V VOUT EFFICIENCY TAIYO YUDEN JMK212BJ475 TAIYO YUDEN JMK212BJ475 PHILIPS PMEG2010 MURATA LQH32CN-100 EQUIVALENT
3460 TA07
Efficiency
4.2V
4.7F
LT3460 SHDN
39.2k
50pF 4.7F 6.3V
3.6V 2.7V
LOAD CURRENT (mA)
3460 TA07a
Step-Up Converter
VOUT 278k 22pF 0.22F
Load Step Response
LT3460 SHDN
VOUT 100mV/DIV
ILOAD
TAIYO YUDEN EMK212BJ105 TAIYO YUDEN UMK212BJ224 CENTRAL SEMICONDUCTOR CMOD4448 TAIYO YUDEN LB2012
3460 TA04
100s/DIV
3460 TA04a
Step-Up Converter
6.3V VOUT 278k 22pF 0.22F
Load Step Response
LT3460 SHDN
VOUT 100mV/DIV
ILOAD
TAIYO YUDEN JMK107BJ105 TAIYO YUDEN UMK212BJ224 CENTRAL SEMICONDUCTOR CMOD4448 TAIYO YUDEN LB2012
3460 TA05
100s/DIV
3460 TA05a
3460fb
LT3460/LT3460-1 APPLICATIONS INFORMATION
Li-Ion Step-Up Converter
2.7V 4.2V 6.3V VOUT 200A 1.6M 124k
LT3460-1 SHDN
TAIYO YUDEN JMK107BJ105 TAIYO YUDEN GMK107BJ105 CENTRAL SEMICONDUCTOR CMDSH-3 MURATA LQH31CN-220
3460 TA08
PACKAGE DESCRIPTION
Package 5-Lead Plastic TSOT-23
(Reference 05-08-1635)
0.62 0.95
2.90 (NOTE
1.22
3.85 2.62
2.80
1.50 1.75 (NOTE
RECOMMENDED SOLDER LAYOUT CALCULATOR 0.30 0.45 PLCS (NOTE
0.95
0.80 0.90 0.20 1.00 DATUM 0.01 0.10
0.30 0.50 0.09 0.20 (NOTE NOTE: DIMENSIONS MILLIMETERS DRAWING SCALE DIMENSIONS INCLUSIVE PLATING DIMENSIONS EXCLUSIVE MOLD FLASH METAL BURR MOLD FLASH SHALL EXCEED 0.254mm JEDEC PACKAGE REFERENCE MO-193
1.90
TSOT-23 0302
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LT3460/LT3460-1 PACKAGE DESCRIPTION
Package 6-Lead Plastic SC70
(Reference 05-08-1638)
0.47 0.65 1.80 2.20 (NOTE
1.16
3.26
0.96
1.80 2.40 1.15 1.35 (NOTE
INDEX AREA (NOTE
RECOMMENDED SOLDER LAYOUT CALCULATOR 0.10 0.40
0.65
0.15 0.30 PLCS (NOTE
0.80 1.00 0.00 0.10 1.00
0.10 0.30 0.10 0.18 (NOTE NOTE: DIMENSIONS MILLIMETERS DRAWING SCALE DIMENSIONS INCLUSIVE PLATING DIMENSIONS EXCLUSIVE MOLD FLASH METAL BURR MOLD FLASH SHALL EXCEED 0.254mm DETAILS INDENTIFIER OPTIONAL, MUST LOCATED WITHIN INDEX AREA EIAJ PACKAGE REFERENCE EIAJ SC-70
SC70 0802
Package 6-Lead Plastic (2mm 2mm)
(Reference 05-08-1703)
0.115 0.56 0.05 SIDES) 2.00 ±0.10 SIDES) 0.38 0.05
0.675 ±0.05 2.50 ±0.05 1.15 ±0.05 0.61 ±0.05 SIDES)
PACKAGE MARK OUTLINE (SEE NOTE 0.25 0.05 0.50 1.42 ±0.05 SIDES)
CHAMFER EXPOSED
(DC6) 1103
0.200
0.75 ±0.05
0.25 0.05 0.50 1.37 ±0.05 SIDES)
RECOMMENDED SOLDER PITCH DIMENSIONS NOTE: DRAWING MADE JEDEC PACKAGE OUTLINE M0-229 VARIATION (WCCD-2) DRAWING SCALE DIMENSIONS MILLIMETERS DIMENSIONS EXPOSED BOTTOM PACKAGE INCLUDE MOLD FLASH. MOLD FLASH, PRESENT, SHALL EXCEED 0.15mm SIDE EXPOSED SHALL SOLDER PLATED SHADED AREA ONLY REFERENCE LOCATION BOTTOM PACKAGE
0.00 0.05
BOTTOM VIEW-EXPOSED
3460fb
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.
LT3460/LT3460-1 TYPICAL APPLICATIONS
SEPIC
0.22F VOUT 50mA 50pF TAIYO YUDEN LMK107BJ105 TAIYO YUDEN LMK107BJ224 SEMICONDUCTOR MBR0520 MURATA LQH32CN-220 EQUIVALENT
3460 TA06
Efficiency
6.5V EFFICIENCY
LT3460 SHDN
LOAD CURRENT (mA)
3460 TA06a
RELATED PARTS
PART NUMBER LT1613 LT1615/LT1615-1 LT1944/LT1944-1 LT1945 LT1961 LTC3400/LTC3400B LTC3401/LTC3402 LT3461/LT3461A LT3464 LT3465/LT3465A DESCRIPTION 550mA (ISW), 1.4MHz, High Efficiency Step-Up DC/DC Converter 300mA/80mA (ISW), Constant Off-Time, High Efficiency StepUp DC/DC Converter Dual Output 350mA/100mA (ISW), Constant Off-Time, High Efficiency Step-Up DC/DC Converter Dual Output, Pos/Neg, 350mA (ISW), Constant Off-Time, High Efficiency Step-Up DC/DC Converter 1.5A (ISW), 1.25MHz, High Efficiency Step-Up DC/DC Converter COMMENTS VIN: 0.9V 10V, VOUT(MAX) 34V, 3mA, ISD<1A, ThinSOT Package VIN: 1.2V 15V, VOUT(MAX) 34V, 20A, ISD<1A, ThinSOT Package VIN: 1.2V 15V, VOUT(MAX) 34V, 20A, ISD<1A, Package VIN: 1.2V 15V, VOUT(MAX) ±34V, 20A, ISD<1A, Package VIN: 25V, VOUT(MAX) 35V, 0.9mA, ISD<6A, MS8E Package
600mA (ISW), 1.2MHz, Synchronous Step-Up DC/DC Converter VIN: 0.85V VOUT(MAX) 19A/300A, ISD<1A, ThinSOT Package 1A/2A (ISW), 3MHz, Synchronous Step-Up DC/DC Converter 0.3A (ISW), 1.3MHz/3MHz, High Efficiency Step-Up DC/DC Converter with Integrated Schottky 0.08A (ISW), High Efficiency Step-Up DC/DC Converter with Integrated Schottky, Output Disconnect Constant Current, 1.2MHz/2.7MHz, High Efficiency White Boost Regulator with Integrated Schottky Diode VIN: 0.5V VOUT(MAX) 38A, ISD<1A, Package VIN: 2.5V 16V, VOUT(MAX) 38V, 2.8mA, ISD<1A, SC70, ThinSOT Packages VIN: 2.3V 10V, VOUT(MAX) 34V, 25A, ISD<1A, ThinSOT Package VIN: 2.7V 16V, VOUT(MAX) 30V, 1.9mA, ISD<1A, ThinSOT Package
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Linear Technology Corporation
(408) 432-1900 FAX: (408) 434-0507
0208 PRINTED
1630 McCarthy Blvd., Milpitas, 95035-7417
www.linear.com
LINEAR TECHNOLOGY CORPORATION 2007

LT®3460/LT3460-1 general purpose step-up converters. LT3460/LT3460-1 s

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