LT3467A

FEATURES n n n n n n n n n n n n n n n LT3467/LT3467A 1.1A Step-Up DC/DC Converter with Integrated Soft-Start DESCRIPTION The LT®3467/LT3467A switching regulators combine a 42V, 1.1A switch with a soft-start function. Pin compatible with the LT1930, its low VCESAT bipolar switch enables the device to deliver high current outputs in a small footprint. The LT3467 switches at 1.3MHz, allowing the use of tiny, low cost and low height inductors and capacitors. The LT3467A switches at 2.1MHz, allowing the use of even smaller components. High inrush current at start-up is eliminated using the programmable soft-start function. A single external capacitor sets the current ramp rate. A constant frequency current mode PWM architecture results in low, predictable output noise that is easy to filter. The high voltage switch on the LT3467/LT3467A is rated at 42V, making the devices ideal for boost converters up to 40V as well as SEPIC and flyback designs. The LT3467 can generate 5V at up to 540mA from a 3.3V supply or 5V at 450mA from four alkaline cells in a SEPIC design. The LT3467A can generate 5V at up to 430mA from a 3.3V supply or 15V at 135mA from a 3.3V supply. The LT3467/ LT3467A are available in a low profile (1mm) 6-lead SOT-23 package and tiny 3mm × 2mm DFN package. L, LT, LTC and LTM are registered trademarks of Linear Technology Corporation. ThinSOT is a trademark of Linear Technology Corporation. All other trademarks are the property of their respective owners. 1.3MHz Switching Frequency (LT3467) 2.1MHz Switching Frequency (LT3467A) Low VCESAT Switch: 330mV at 1.1A High Output Voltage: Up to 40V Wide Input Range: 2.4V to 16V Dedicated Soft-Start Pin 5V at 540mA from 3.3V Input (LT3467) 5V at 430mA from 3.3V Input (LT3467A) 12V at 270mA from 5V Input (LT3467) 12V at 260mA from 5V Input (LT3467A) Uses Small Surface Mount Components Low Shutdown Current: Phase Lead Zero : Z 4 = gmp VOUT CPL RESR COUT R1 RL VC RC CC RO + gma 1.255V REFERENCE 1 2 • π • R1 • CPL 1 Phase Lead Pole : P4 = R1 • R2 2 • π • CPL • R1+ R2 The current mode zero is a right-half plane zero which can be an issue in feedback control design, but is manageable with proper external component selection. CC: COMPENSATION CAPACITOR COUT: OUTPUT CAPACITOR CPL: PHASE LEAD CAPACITOR gma: TRANSCONDUCTANCE AMPLIFIER INSIDE IC gmp: POWER STAGE TRANSCONDUCTANCE AMPLIFIER RC: COMPENSATION RESISTOR RL: OUTPUT RESISTANCE DEFINED AS VOUT DIVIDED BY ILOAD(MAX) RO: OUTPUT RESISTANCE OF gma R1, R2: FEEDBACK RESISTOR DIVIDER NETWORK RESR: OUTPUT CAPACITOR ESR Figure 6. Boost Converter Equivalent Model 10 + – R2 3467 F06 3467afd LT3467/LT3467A APPLICATIONS INFORMATION Using the circuit of Figure 2 as an example, the following table shows the parameters used to generate the Bode plot shown in Figure 7. 50 40 30 20 GAIN (dB) 10 0 –10 –20 –30 –40 –50 100 GAIN PHASE 1k 10k 100k FREQUENCY (Hz) 0 –45 –90 –135 PHASE (DEG) –180 –225 –270 –315 –360 –405 –450 1M 3467 F07 Table 3. Bode Plot Parameters PARAMETER RL COUT RESR RO CC CPL RC R1 R2 VOUT VIN gma gmp L fS VALUE 10.4 15 10 0.4 60 3.3 100 402 133 5 3.3 35 7.5 2.7 1.3* UNITS Ω μF mΩ MΩ pF pF kΩ kΩ kΩ V V μmho mho μH MHz COMMENT Application Specific Application Specific Application Specific Not Adjustable Not Adjustable Adjustable Not Adjustable Adjustable Adjustable Application Specific Application Specific Not Adjustable Not Adjustable Application Specific Not Adjustable Figure 7. Bode Plot of 3.3V to 5V Application *2.1MHz for LT3467A From Figure 7, the phase is –138° when the gain reaches 0dB giving a phase margin of 42°. This is more than adequate. The crossover frequency is 37kHz. TYPICAL APPLICATIONS Lithium-Ion to 6V Step-Up DC/DC Converter L1 2.2μH D1 R1 501k C3 1.8pF FB R2 133k C2 15μF VOUT 6V 275mA AT VIN = 2.7V 490mA AT VIN = 3.8V 590mA AT VIN = 4.2V 95 90 85 EFFICIENCY (%) 80 75 70 65 60 C1, C2: X5R OR X7R, 6.3V D1: ON SEMICONDUCTOR MBRM120 L1: SUMIDA CR43-2R2 3467 TA02 Li-Ion to 6V VIN 2.7V TO 4.2V VIN C1 2.2μF SHDN VIN = 4.2V VIN = 3.8V VIN = 2.7V SW SHDN LT3467 SS GND C4 0.047μF 55 50 50 100 200 300 400 IOUT (mA) 500 600 700 3467 TA02b 3467afd 11 LT3467/LT3467A TYPICAL APPLICATIONS 4-Cell to 5V SEPIC Converter L1 10μH C1 2.2μF SHDN 4-CELL BATTERY C4 0.047μF C1, C3: X5R or X7R, 10V C2: X5R or X7R, 6.3V C3 1μF D1 VOUT 5V 325mA AT VIN = 4V 400mA AT VIN = 5V 450mA AT VIN = 6.5V L2 10μH 84.5k C2 10μF 4V TO 6.5V VIN SW SHDN LT3467 FB SS GND 255k C5 4.7pF D1: PHILIPS PMEG 2010 L1, L2: MURATA LQH32CN100K33L 3467 TA03 5V to 40V Boost Converter L1 2.7μH C1 4.7μF SHDN D1 VOUT 40V 20mA R1 412k C2 1μF R2 13.3k VIN 5V VIN SHDN LT3467 SS GND SW FB C3 0.1μF C1: X5R or X7R, 6.3V C2: X5R or X7R, 50V D1: ON SEMICONDUCTOR, MBRM140 L1: SUMIDA CD43-2R7 3467 TA04a ±15V Dual Output Converter with Output Disconnect L1 10μH C1 2.2μF OFF ON C4 1μF D1 15V 100mA VIN 5V VIN SHDN LT3467 SS SW C5 1μF R3 1Ω D2 R1 147k C2 2.2μF R2 13.3k C3 2.2μF 3467 TA05 FB GND C6 0.047μF C1: X5R or X7R, 6.3V C2 TO C5: X5R or X7R, 16V D1 TO D4: PHILIPS PMEG 2005 L1: SUMIDA CR43-100 D3 R4 1Ω D4 –15V 100mA 3467afd 12 LT3467/LT3467A TYPICAL APPLICATIONS 9V, 18V, –9V Triple Output TFT-LCD Bias Supply with Soft-Start D1 D2 C3 0.1μF VIN 3.3V C1 2.2μF VSHDN VIN SHDN LT3467 SS 3.3V 0V C7 0.1μF C1: X5R OR X7R, 6.3V C2,C3, C5, C6: X5R OR X7R, 10V C4: X5R OR X7R, 25V D1 TO D4: PHILIPS BAT54S OR EQUIVALENT D5: PHILIPS PMEG 2005 L1: PANASONIC ELT5KT4R7M GND C2 0.1μF D4 D3 C6 1μF FB R2 20k L1 4.7μH D5 9V 220mA SW R1 124k C5 10μF 9V OUTPUT 5V/DIV –9V OUTPUT 5V/DIV C4 1μF 18V 10mA Start-Up Waveforms 18V OUTPUT 10V/DIV IL1 0.5A/DIV 2ms/DIV 3467 TA06b –9V 10mA 3467 TA06a 8V, 23V, –8V Triple Output TFT-LCD Bias Supply with Soft-Start D1 D2 C3 0.1μF D3 C4 0.1μF D4 C5 0.1μF 23V 10mA C6 1μF Start-Up Waveforms 8V OUTPUT 5V/DIV –8V OUTPUT 5V/DIV VIN 3.3V C1 2.2μF VSHDN VIN L1 4.7μH D7 8V 270mA SW R1 113k C7 10μF R2 21k 23V OUTPUT 10V/DIV SHDN LT3467 SS GND C9 0.1μF FB 3.3V 0V C2 0.1μF D5 D6 C1: X5R OR X7R, 6.3V C2 TO C4, C7, C8: X5R OR X7R, 10V C5: X5R OR X7R, 16V C6: X5R OR X7R, 25V D1 TO D6: PHILIPS BAT54S OR EQUIVALENT D7: PHILIPS PMEG 2005 L1: PANASONIC ELT5KT4R7M IL1 0.5A/DIV C8 1μF 3467 TA07a 2ms/DIV 3467 TA07b –8V 10mA 3467afd 13 LT3467/LT3467A TYPICAL APPLICATIONS Single Li-Ion Cell to 5V Boost Converter VIN 2.6V TO 4.2V C1 4.7μF VIN OFF ON L1 0.9μH D1 R1 8.06k C4* 75pF VOUT 5V 600mA AT VIN = 4.2V 360mA AT VIN = 3.3V 250mA AT VIN = 2.6V 95 90 85 EFFICIENCY (%) 80 75 70 65 60 3467 TA09a Efficiency SW SHDN LT3467A SS FB GND R2 2.67k VIN = 3.3V VIN = 2.6V VIN = 4.2V C3 0.047μF C2* 22μF C1, C2: X5R OR X7R, 6.3V D1: PHILIPS PMEG 2010 L1: FDK MIPW3226D0R9M *C2 CAN BE 10μF IN A 1210 OR LARGER PACKAGE WITH THE ADDITION OF C4, OTHERWISE C4 IS OPTIONAL 55 50 50 100 150 200 250 300 350 400 450 500 IOUT (mA) 3467 TA09b 2.6V-3.3V to 5V Boost Converter L1 1.5μH D1 R1 8.06k C4 56pF C2 10μF VOUT 5V 430mA AT VIN = 3.3V 270mA AT VIN = 2.6V 90 85 80 EFFICIENCY (%) 75 70 65 60 C1, C2: X5R OR X7R, 6.3V D1: PHILIPS PMEG 2010 L1: FDK MIP3226D1R5M 3467 TA08a Efficiency VIN 2.6V TO 3.3V C1 4.7μF VIN OFF ON SW SHDN LT3467A SS FB GND R2 2.67k VIN = 2.6V VIN = 3.3V C3 0.047μF 55 50 50 100 150 200 250 300 350 400 450 500 IOUT (mA) 3467 TA08b 3.3V to 15V, 135mA Step-Up Converter L1 6.8μH D1 R1 16.5k C4 68pF R2 1.5k C2 2.2μF 90 VOUT 15V 135mA EFFICIENCY (%) 80 70 60 50 40 30 Efficiency VIN 3.3V C1 4.7μF VIN OFF ON SW SHDN LT3467A SS FB GND C3 0.047μF C1: X5R OR X7R, 6.3V C2: X5R OR X7R, 16V D1: PHILIPS PMEG 2010 L1: SUMIDA CMD4D13-6R8MC 3467 TA10a 20 40 60 80 100 IOUT (mA) 120 140 160 3467 TA10b 3467afd 14 LT3467/LT3467A PACKAGE DESCRIPTION DDB Package 8-Lead Plastic DFN (3mm × 2mm) (Reference LTC DWG # 05-08-1702 Rev B) 0.61 0.05 (2 SIDES) 0.70 0.05 2.55 0.05 1.15 0.05 PACKAGE OUTLINE 0.25 0.05 0.50 BSC 2.20 0.05 (2 SIDES) RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS NOTE: 1. DRAWING CONFORMS TO VERSION (WECD-1) IN JEDEC PACKAGE OUTLINE M0-229 2. DRAWING NOT TO SCALE 3. ALL DIMENSIONS ARE IN MILLIMETERS 4. DIMENSIONS OF EXPOSED PAD ON BOTTOM OF PACKAGE DO NOT INCLUDE MOLD FLASH. MOLD FLASH, IF PRESENT, SHALL NOT EXCEED 0.15mm ON ANY SIDE 5. EXPOSED PAD SHALL BE SOLDER PLATED 6. SHADED AREA IS ONLY A REFERENCE FOR PIN 1 LOCATION ON THE TOP AND BOTTOM OF PACKAGE PIN 1 BAR TOP MARK (SEE NOTE 6) 2.00 0.10 (2 SIDES) 0.56 0.05 (2 SIDES) 0.75 0.05 0.25 PIN 1 R = 0.20 OR 0.25 45 CHAMFER (DDB8) DFN 0905 REV B 3.00 0.10 (2 SIDES) R = 0.05 TYP R = 0.115 TYP 5 0.40 8 0.10 0.200 REF 4 0.05 2.15 0.05 (2 SIDES) 1 0.50 BSC 0 – 0.05 BOTTOM VIEW—EXPOSED PAD S6 Package 6-Lead Plastic TSOT-23 (Reference LTC DWG # 05-08-1636) 0.62 MAX 0.95 REF 2.90 BSC (NOTE 4) 1.22 REF 3.85 MAX 2.62 REF 1.4 MIN 2.80 BSC 1.50 – 1.75 (NOTE 4) PIN ONE ID RECOMMENDED SOLDER PAD LAYOUT PER IPC CALCULATOR 0.95 BSC 0.30 – 0.45 6 PLCS (NOTE 3) 0.80 – 0.90 0.20 BSC 1.00 MAX DATUM ‘A’ 0.01 – 0.10 0.30 – 0.50 REF NOTE: 1. DIMENSIONS ARE IN MILLIMETERS 2. DRAWING NOT TO SCALE 3. DIMENSIONS ARE INCLUSIVE OF PLATING 4. DIMENSIONS ARE EXCLUSIVE OF MOLD FLASH AND METAL BURR 5. MOLD FLASH SHALL NOT EXCEED 0.254mm 6. JEDEC PACKAGE REFERENCE IS MO-193 0.09 – 0.20 (NOTE 3) 1.90 BSC S6 TSOT-23 1005 3467afd Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use. Linear Technology Corporation makes no representation that the interconnection of its circuits as described herein will not infringe on existing patent rights. 15 LT3467/LT3467A TYPICAL APPLICATIONS VIN 5V L1 4.7μH C1 2.2μF SHDN D1 R1 115k Efficiency VOUT 12V 270mA C4* 22pF 90 85 80 EFFICIENCY (%) C2 10μF 75 70 65 60 55 50 50 100 150 200 250 IOUT (mA) 300 350 VIN SHDN LT3467 SS GND SW FB R2 13.3k C3 0.047μF C1: X5R OR X7R, 6.3V C2: X5R OR X7R, 16V D1: PHILIPS PMEG 2010 L1: SUMIDA CR43-4R7 *OPTIONAL 3467 F08a Figure 8. 5V to 12V, 270mA Step-Up Converter L1 3.3μH D1 R1 115k C4 12pF R2 13.3k C2 10μF VOUT 12V 260mA 3467 F08b Efficiency 95 90 85 EFFICIENCY (%) 80 75 70 65 60 55 50 50 100 150 200 IOUT (mA) 250 300 3467 F09b VIN 5V C1 4.7μF VIN OFF ON SW SHDN LT3467A SS FB GND C3 0.047μF C1: X5R OR X7R, 6.3V C2: X5R OR X7R, 16V D1: PHILIPS PMEG 2010 L1: SUMIDA CDRH4D18-3R3 3467 F09a Figure 9. 5V to 12V, 260mA Step-Up Converter RELATED PARTS PART NUMBER LT1615/LT1615-1 LT1618 LTC1700 LTC1871 LT1930/LT1930A LT1946/LT1946A LT1961 LTC3400/ LTC3400B LTC3401 LTC3402 LT3464 DESCRIPTION 300mA/80mA (ISW), High Efficiency Step-Up DC/DC Converter 1.5A (ISW), 1.25MHz, High Efficiency Step-Up DC/DC Converter No RSENSE™, 530kHz, Synchronous Step-Up DC/DC Controller Wide Input Range, 1MHz, No RSENSE Current Mode Boost, Flyback and SEPIC Controller 1A (ISW), 1.2MHz/2.2MHz, High Efficiency Step-Up DC/DC Converter 1.5A (ISW), 1.2MHz/2.7MHz, High Efficiency Step-Up DC/DC Converter with Soft-Start 1.5A (ISW), 1.25MHz, High Efficiency Step-Up DC/DC Converter 600mA (ISW), 1.2MHz, Synchronous Step-Up DC/DC Converter 1A (ISW), 3MHz, Synchronous Step-Up DC/DC Converter 2A (ISW), 3MHz, Synchronous Step-Up DC/DC Converter COMMENTS VIN: 1V to 15V, VOUT(MAX) = 34V, IQ = 20μA, ISD < 1μA, ThinSOT Package 90% Efficiency, VIN: 1.6V to 18V, VOUT(MAX) = 35V, IQ = 1.8mA, ISD < 1μA, MS Package 95% Efficiency, VIN: 0.9V to 5V, IQ = 200μA, ISD < 10μA, MS Package 92% Efficiency, VIN: 2.5V to 36V, IQ = 250μA, ISD < 10μA, MS Package High Efficiency, VIN: 2.6V to 16V, VOUT(MAX) = 34V, IQ = 4.2mA/5.5mA, ISD < 1μA, ThinSOT Package High Efficiency, VIN: 2.45V to 16V, VOUT(MAX) = 34V, IQ = 3.2mA, ISD < 1μA, MS8 Package 90% Efficiency, VIN: 3V to 25V, VOUT(MAX) = 35V, IQ = 0.9mA, ISD < 6μA, MS8E Package 92% Efficiency, VIN: 0.85V to 5V, VOUT(MAX) = 5V, IQ = 19μA/300μA, ISD < 1μA, ThinSOT Package 97% Efficiency, VIN: 0.5V to 5V, VOUT(MAX) = 5.5V, IQ = 38μA, ISD < 1μA, MS Package 97% Efficiency, VIN: 0.5V to 5V, VOUT(MAX) = 5.5V, IQ = 38μA, ISD < 1μA, MS Package VIN: 2.3V to 10V, VOUT(MAX) = 34V, IQ = 25μA, ISD < 1μA, ThinSOT Package 3467afd 85mA (ISW), High Efficiency Step-Up DC/DC Converter with Integrated Schottky and PNP Disconnect No RSENSE is a trademark of Linear Technology Corporation. 16 Linear Technology Corporation (408) 432-1900 ● FAX: (408) 434-0507 ● LT 1208 REV D • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 www.linear.com © LINEAR TECHNOLOGY CORPORATION 2003