LT3472 Boost and Inverting DC/DC Converter for CCD Bias DESCRIPTIO U FEATURES ■ ■ ■ ■ ■ ■ ■ ■ ■ Generates 15V at 20mA, –8V at 50mA from a Li-Ion Cell Internal Schottky Diodes VIN Range: 2.2V to 16V Output Voltages Up to ±34V Capacitor-Programmable Soft-Start Sequencing: Positive Output Reaches 88% of Final Value Before Negative Output Begins Requires Only One Resistor to Set Output Voltage Constant Switching Frequency Ensures Low Noise Outputs Available in a 10-Lead (3mm × 3mm) DFN Package U APPLICATIO S ■ ■ ■ ■ CCD Bias TFT LCD Bias OLED Bias ± Rail Generation for Op Amps The LT®3472 dual channel switching regulator generates positive and negative outputs for biasing CCD imagers. The device delivers up to –8V at 50mA and 15V at 20mA from a lithium-ion cell, providing bias for many popular CCD imagers. Switching at 1.1MHz, the LT3472 uses tiny, low profile capacitors and inductors and generates low noise outputs that are easy to filter. Schottky diodes are internal and the output voltages are set with one resistor per channel, reducing external component count. The entire solution is less than 1mm profile and occupies just 50mm2. Internal sequencing circuitry disables the negative channel until the positive channel has reached 88% of its final value, ensuring that the sum of the two outputs is always positive. Separate soft-start capacitors for each output allow the ramp of each output to be independently controlled. The LT3472 is available in a low profile (0.75mm) 10-pin 3mm × 3mm DFN package. , LTC and LT are registered trademarks of Linear Technology Corporation. U TYPICAL APPLICATIO Li-Ion CCD Bias Supply VIN 3V TO 4.2V Conversion Efficiency 2.2µF 22µH 85 1µF 47µH 80 POS CHANNEL VPOS 15V 20mA SWP VIN VPOS SWN DN 550k 47µH LT3472 FBP 4.7pF 320k FBN 10pF SHDN 70 NEG CHANNEL 65 60 55 50 SHDN SSP 2.2µF VNEG –8V 50mA EFFICIENCY (%) 75 GND 100nF 45 SSN 100nF 2.2µF 3472 TA01a 40 0 10 30 20 LOAD CURRENT (mA) 40 50 3472 TA01b 3472f 1 LT3472 U W W W ABSOLUTE AXI U RATI GS U W U PACKAGE/ORDER I FOR ATIO (Note 1) VIN, SHDN Voltage ................................................... 16V SWP, SWN, VPOS Voltage ....................................... 36V DN Voltage ............................................................ –36V FBP, FBN, SSP, SSN Voltage ................................... 10V Maximum Junction Temperature .......................... 125°C Operating Temperature Range Extended Commercial ......................... –40°C to 85°C Storage Temperature Range ................. – 65°C to 125°C ORDER PART NUMBER TOP VIEW 10 VPOS 9 SSP SWP 1 VIN 2 SHDN 3 SWN 4 7 SSN DN 5 6 FBN 11 LT3472EDD 8 FBP DFN PART MARKING DD PACKAGE 10-LEAD (3mm × 3mm) PLASTIC DFN TJMAX = 125°C, θJA = 43°C/W, θJC = 3°C/W EXPOSED PAD IS GND (PIN 11) MUST BE SOLDERED TO PCB LBGC Consult LTC Marketing for parts specified with wider operating temperature ranges. ELECTRICAL CHARACTERISTICS The ● denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VIN = 3V, SHDN = 3V unless otherwise noted. PARAMETER CONDITIONS MIN Minimum Operation Voltage TYP 2.2 SHDN = 3V, Not Switching SHDN = 0V 16 V 1 mA µA 0.8 V ● SHDN Voltage Low SHDN Pin Bias Current 2.8 0.1 ● SHDN Voltage High 0.3 SHDN = 3V 35 Positive Feedback Voltage ● 1.2 Negative Feedback Voltage ● –5 UNITS V Maximum Operation Voltage Supply Current MAX V µA 1.25 1.3 0 5 V mV Positive Feedback Voltage Line Regulation 0.01 %/V Negative Feedback Voltage Line Regulation 0.008 mV/V FBP Current FBP = VFBP ● 24.5 25 25.3 µA FBN Current FBN = VFBN ● 24.5 25 25.3 µA 1.02 1.1 1.18 V 1.4 MHz FBP to Start Negative Channel Switching Frequency 0.9 1.1 Maximum Duty Cycle (Both Channels) ● 88 92 % Positive Channel Switch Current Limit ● 250 350 mA ● 300 Negative Channel Switch Current Limit 400 mA Positive Channel Switch VCESAT ISWP = 200mA 245 mV Negative Channel Switch VCESAT ISWN = 200mA 400 mV Switch Leakage Current (Both Channels) VSW = 5V 0.01 5 µA Schottky DP Forward Drop IDP = 150mA 700 950 mV Schottky DN Forward Drop IDN = 150mA 750 1000 mV Schottky Leakage Current (Both Channels) VR = 36V 4 µA Note 1: Absolute Maximum Ratings are those values beyond which the life of a device may be impaired. Note 2: The LT3472E is guaranteed to meet specified performance from 0°C to 70°C. Specifications over the –40°C to 85°C operating range are assured by design, characterization and correlation with statistical process controls. 3472f 2 LT3472 U W TYPICAL PERFOR A CE CHARACTERISTICS Minimum FBP Voltage to Enable Inverter Quiescent Current 3.1 1.30 1.12 3.0 1.28 2.9 FBP VOLTAGE (V) 1.11 1.10 VFB1 (V) QUIESCENT CURRENT (mA) FBP Voltage 1.13 2.8 1.09 1.08 2.7 1.26 1.24 1.07 1.22 2.6 1.06 2.5 –50 50 0 TEMPERATURE (°C) 1.05 –50 100 50 0 TEMPERATURE (°C) 1.20 100 –50 50 0 100 TEMPERATURE (°C) 3472 G01 3472 G02 FBN Voltage FBP BIAS CURRENT (µA) 0 –5 50 0 TEMPERATURE (°C) 100 26.0 FBN BIAS CURRENT (µA) 26.0 5 25.5 25.0 24.5 24.0 –50 50 0 TEMPERATURE (°C) 100 25.5 25.0 24.5 24.0 –50 50 0 100 TEMPERATURE (°C) 3472 G04 3472 G05 SHDN Pin Bias Current POSITIVE SWITCH SATURATION VOLTAGE (mV) 250 200 150 100 50 0 0 5 10 15 SHDN VOLTAGE (V) 3472 G06 Positive Channel Switch VCESAT 300 SHDN CURRENT (µA) FBN VOLTAGE (mV) FBN Bias Current FBP Bias Current 10 –10 –50 3472 G03 20 3472 G07 350 90°C 300 25°C 250 –45°C 200 150 100 50 0 0 50 100 150 200 250 SWITCH CURRENT (mA) 300 3472 G08 3472f 3 LT3472 U W TYPICAL PERFOR A CE CHARACTERISTICS 25°C 90°C 300 –45°C 250 200 150 100 50 0 0 0.2 0.4 0.8 0.6 SCHOTTKY FORWARD DROP (V) 1.0 3472 G09 NEGATIVE SCHOTTKY FORWARD CURRENT (mA) 400 350 Negative Channel Schottky I-V Characteristic Negative Channel Switch VCESAT NEGATIVE SWITCH SATURATION VOLTAGE (mV) POSITIVE SCHOTTKY FORWARD CURRENT (mA) Positive Channel Schottky I-V Characteristic 600 500 90°C 25°C 400 –45°C 300 200 100 0 0 50 100 150 200 SWITCH CURRENT (mA) 250 3472 G10 350 25°C 300 250 90°C 200 –45°C 150 100 50 0 0 0.2 0.4 0.8 0.6 SCHOTTKY FORWARD DROP (V) 1.0 3472 G11 3472f 4 LT3472 U U U PI FU CTIO S SWP (Pin 1): Switch Pin for Positive (Boost) Channel. Connect boost inductor here. VIN (Pin 2): Input Supply Pin. Must be locally bypassed with a X5R or X7R type ceramic capacitor. SHDN (Pin 3): Shutdown Pin. Connect to 0.8V or higher to enable device, 0.3V or less to disable device. SWN (Pin 4): Switch Pin for Negative (Inverter) Channel. Connect inverter input inductor and flying capacitor here. DN (Pin 5): Anode of Internal Schottky for Inverter. Connect inverter output inductor and flying capacitor here. FBN (Pin 6): Feedback Pin for Inverter. Connect feedback resistor R2 from this pin to VO2. Choose R2 according to VO2 = 1.25 • R2/50k. Pin voltage = 0V when regulated. SSN (Pin 7): Soft Start-Up Pin for Inverter. Connect a cap here for soft start-up. Leave open for quick start-up. This pin is connected to 1.25V with a 50k resistor internally. FBP (Pin 8): Feedback Pin for Boost. Connect boost feedback resistor R1 from this Pin to VO1. Choose R1 according to VO1 = 1.25 • (1 + R1/50k). Pin voltage = 1.25V when regulated. SSP (Pin 9): Soft Start-Up Pin for Boost. Connect a cap here for soft start-up. Leave open for quick start-up. This pin is connected to 1.25V with a 50k resistor internally. VPOS (Pin 10): Output Pin for Boost. Connect boost output capacitor here. GND (Exposed Pad) (Pin 11): GND Pin. Tie directly to ground plane through multiple vias under the package for optimum thermal performance. W BLOCK DIAGRA SWP 1 COMPARATOR – FBP 8 – A1 50k + DP X1 A2 10 VPOS DRIVER 1 R Q1 Q S + – VIN 2 ∑ + VREF 1.25V 50k RAMP GENERATOR 11 GND 1.2MHz OSCILLATOR 3 SHDN 4 SWN 5 DN COMPARATOR + FBN 6 – SSN DRIVER 2 X2 – A3 A4 R S + 7 – 50k ∑ 1.25V 50k SSP 9 Q2 Q + RAMP GENERATOR DN 3472 BD Figure 1. LT3472 Block Diagram 3472f 5 LT3472 U W U U APPLICATIO S I FOR ATIO Operation Inductor Selection The LT3472 uses a constant frequency, current mode control scheme to provide excellent line and load regulation. Operation can be best understood by referring to the block diagram in Figure 1. At the start of each oscillator cycle, the SR latch X1 is set, which turns on the power switch Q1. A voltage proportional to the switch current is added to a stabilizing ramp and the resulting sum is fed into the positive terminal of the PWM comparator A2. When this voltage exceeds the level at the negative input of A2, the SR latch X1 is reset turning off the power switch Q1. The level at the negative input of A2 is set by the error amplifier A1, and is simply an amplified version of the difference between the feedback voltage and the reference voltage of 1.25V. In this manner, the error amplifier sets the correct peak current level to keep the output in regulation. If the error amplifier’s output increases, more current is delivered to the output; if it decreases, less current is delivered. The second channel is an inverting converter. The basic operation is the same as the positive channel. The SR latch X2 is also set at the start of each oscillator cycle. The power switch Q2 is turned on at the same time as Q1. The turn off of Q2 is determined by its own feedback loop, which consists of error amplifier A3 and PWM comparator A4. The reference voltage of this negative channel is ground. A 22µH inductor is recommended for LT3472 step-up channel. The inverter channel can use a 22µH or 47µH inductor. 47µH inductors will provide slightly more current. Small size and high efficiency are the major concerns for most LT3472 applications. Inductors with low core losses and small DCR (copper wire resistance) at 1.1MHz are good choices for LT3472 applications. Some inductors in this category with small size are listed in Table 1. The efficiency comparison of different inductors is shown in Figure 3. 85 LQH32CN220 EFFICIENCY (%) 80 LQH2MCN220 70 60 0 85 BOOST LOAD = 20mA TOKO 1067FB-220M 75 LQH2MCN220 70 ISWN 100mA/DIV 60 0 Figure 2. Switching Waveforms 3472 FO4 30 LQH32CN220 65 500ns/DIV 10 15 20 25 LOAD CURRENT IO1 (mA) 80 VSWN 20V/DIV VIN = 3.6V VPOS = 15V, 20mA VNEG = –7.5V, 30mA 5 3473F02a F02a 3472 EFFICIENCY (%) IL1 100mA/DIV TOKO 1067FB-220M 75 65 Switching waveforms with typical load conditions are shown in Figure 2. VSWP 20V/DIV INVERTER LOAD = 20mA 5 10 15 20 25 LOAD CURRENT IO2 (mA) 30 3473F02b F02a 3472 Figure 3. Efficiency Comparison of Different Inductors 3472f 6 LT3472 U W U U APPLICATIO S I FOR ATIO Table 1. Recommended Inductors Part No. Inductance DCR Current Manufacturer (µH) (Ω) Rating (mA) LQH32CN220 LQH32CN470 LQH2MCN220 LQH2MCN470 22 47 22 47 0.71 1.3 2.1 5.1 250 170 185 120 Murata (814) 237-1431 www.murata.com D1067FB-220M 22 2.0 270 TOKO (408) 432-8281 www.tokoam.com ELJPC220KF 22 4.0 160 Panasonic (714) 373-7334 www.panasonic.com CDRH3D16-220 22 0.53 350 Sumida (847) 956-0666 www.sumida.com LB2012B220M LEM2520-220 22 22 1.7 5.5 75 125 Taiyo Yuden (408) 573-4150 www.t-yuden.com Capacitor Selection The small size of ceramic capacitors makes them suitable for LT3472 applications. X5R and X57 types of ceramic capacitors are recommended because they retain their capacitance over wider voltage and temperature ranges than other types such as Y5V or Z5U. A 2.2µF input capacitor and a 2.2µF output capacitor are sufficient for most LT3472 applications. 1A. The selection of inductor and capacitor value should ensure the peak of the inrush current to be below 1A. The peak inrush current can be calculated as follows: ⎡ α VIN – 0.6 ⎛ ω⎞⎤ • EXP⎢ – • arctan ⎜ ⎟ ⎥ • ⎝ α⎠⎦ L•ω ⎣ ω IP = ⎡ ⎛ ω⎞⎤ SIN⎢arctan• ⎜ ⎟ ⎥ ⎝ α⎠⎦ ⎣ r + 1.5 α= 2•L 1 r – ω= L • C 4 • L2 where L is the inductance, r is the resistance of the inductor and C is the output capacitance. For low DCR inductors, which is usually the case for this application, the peak inrush current can be simplified as follows: IP = ⎛ α π⎞ VIN – 0.6 • EXP⎜ – • ⎟ L•ω ⎝ ω 2⎠ Table 3 gives inrush peak currents for some component selections. Note that inrush current is not a concern if the input voltage rises slowly. Table 3. Inrush Peak Current Table 2. Recommended Ceramic Capacitor Manufacturers URL VIN (V) r (Ω) L (µH) C (µF) IP (A) 5 0.5 22 2.2 0.89 Manufacturer Phone Taiyo Yuden (408) 573-4150 www.t-yuden.com 3.6 0.7 22 2.2 0.59 Murata (814) 237-1431 www.murata.com 3.6 2.1 22 2.2 0.46 Kemet (408) 986-0424 www.kemet.com 3.6 1.3 47 1 0.32 3.6 0.7 22 1 0.46 Inrush Current The LT3472 uses internal Schottky diodes. When supply voltage is abruptly applied to VIN pin, for the positive channel, the voltage difference between VIN and VPOS generates inrush current flowing from input through the inductor LP and the internal Schottky diode DP to charge the output capacitor COP. For the inverter channel, there is a similar inrush current flowing from input through the inductor LN1 path, charging the capacitor CNF, and returning through the internal Schottky diode DN. The maximum current the Schottky diodes in the LT3472 can sustain is External Diode Selection As stated previously the LT3472 has internal Schottky diodes. The Schottky diode DP is sufficient for most stepup applications. However, for high current inverter applications, a properly selected external Schottky diode in parallel with DN can improve efficiency. For external diode selection, both forward voltage drop and diode capacitance need to be considered. Schottky diodes rated for higher current usually have lower forward voltage drop 3472f 7 LT3472 U W U U APPLICATIO S I FOR ATIO and larger capacitance, which can cause significant switching losses at 1.1MHz switching frequency. Some recommended Schottky diodes are listed in Table 4. In order to maintain accuracy, high precision resistors are preferred (1% is recommended). Soft-Start Table 4. Recommended Schottky Diodes Part No. CMDSH-3 CMDSH2-3 Forward Current (mA) 100 200 Forward Voltage Drop (V) Diode Capacitance (pF) Manufacturer 0.58 @100mA 7 @ 10V 0.49 @ 200mA 15 @ 10V Central Semiconductor (631) 435-1110 www.centralsemi.com Setting the Output Voltages The LT3472 has an accurate feedback resistor of 50k for each channel. Only one resistor is needed to set the output voltage for each channel. The output voltage can be set according to the following formulas: The LT3472 has independent soft-start control for each channel. As shown in Figure 1, the SSP and SSN pins have an internal resistor of 50k pulling up to 1.25V, respectively. By connecting a capacitor from the SSP or SSN pin to ground, the ramp of each output can be programmed individually. If SSP or SSN is open or pull higher than 1.25V, the corresponding output will ramp up quickly. The waveforms with and without soft-start for the Boost channel are shown in Figure 4. The waveforms with and without soft-start for the negative channel are shown in Figure 5. Start Sequencing The LT3472 has internal sequencing circuitry that inhibits the negative channel from operating until feedback voltage of the step-up channel reaches about 1.1V, ensuring that R1 ⎞ ⎛ VPOS = 1.25 • ⎜ 1 + ⎟ ⎝ 50k ⎠ ⎛ R2 ⎞ VNEG = –1.25 • ⎜ ⎟ ⎝ 50k ⎠ VSSP 1V/DIV VSSP 2V/DIV VPOS 5V/DIV VPOS 5V/DIV IIN 100mA/DIV IIN 200mA/DIV 1ms/DIV 3472 FO4a Figure 4a. VSSP, VPOS, IIN with 100nF on SSP VSSN 1V/DIV 100µs/DIV 3472 FO4b Figure 4b. VSSP, VPOS, IIN with SSP Open VSSN 2V/DIV VNEG 5V/DIV VNEG 5V/DIV IIN 200mA/DIV IIN 100mA/DIV 500µs/DIV 3472 FO5a Figure 5a. VSSN, VNEG, IIN with 100nF on SSN 100µs/DIV 3472 FO5b Figure 5b. VSSN, VNEG, IIN with SSN Open 3472f 8 LT3472 U W U U APPLICATIO S I FOR ATIO the sum of the two outputs is always positive. The sequencing is shown in Figure 6. Board Layout Consideration As with all switching regulators, careful attention must be paid to the PCB board layout and component placement. To maximize efficiency, switch rise and fall times are made as short as possible. To prevent electromagnetic interfer- ence (EMI) problems, proper layout of the high frequency switching path is essential. The voltage signals of the SWP and SWN pins have rise and fall times of a few ns. Minimize the length and area of all traces connected to the SWP and SWN pins and always use a ground plane under the switching regulator to minimize interplane coupling. Recommended component placement is shown in Figure 7. VPOS 5V/DIV COP CIN LP RFBP VNEG 5V/DIV VSHDN 5V/DIV CFBP CSSP LN1 100µs/DIV 3472 FO6 Figure 6. Start-Up Sequencing RFBN CNF CFBN CSSN LN2 CON 3472 F06 Figure 7. Recommended Component Placement 3472f 9 LT3472 U TYPICAL APPLICATIO S VIN 3V TO 4.2V CIN 2.2µF LN1 47µH LP 22µH VPOS 15V 20mA RFBP 550k SWP VPOS VIN CNF 1µF SWN DN LT3472 FBP RFBN 320k CFBP, 4.7pF FBN SHDN CFBN 10pF SHDN SSP GND VNEG –8V 50mA SSN CSSP 100nF COP 2.2µF LN2 47µH CSSN 100nF CIN: TAIYO YUDEN JMK107BJ225 COP: TAIYO YUDEN EMK316BJ225 CNF: TAIYO YUDEN EMK212BJ105 CON: TAIYO YUDEN LMK212BJ225 LP: MURATA LQH32CN220 LN1, LN2: MURATA LQH32CN470 VPOS Load Step Response CON 2.2µF 3472 TA02 VNEG Load Step Response IPOS 15mA 25mA INEG –20mA –30mA VPOS 20mV/DIV VNEG 10mV/DIV 20µs/DIV 3472 TA04 50µs/DIV 3472 TA05 3472f 10 LT3472 U PACKAGE DESCRIPTIO DD Package 10-Lead Plastic DFN (3mm × 3mm) (Reference LTC DWG # 05-08-1699) R = 0.115 TYP 6 0.38 ± 0.10 10 0.675 ±0.05 3.50 ±0.05 1.65 ±0.05 2.15 ±0.05 (2 SIDES) 3.00 ±0.10 (4 SIDES) PACKAGE OUTLINE 1.65 ± 0.10 (2 SIDES) PIN 1 TOP MARK (SEE NOTE 6) (DD10) DFN 1103 5 0.200 REF 0.25 ± 0.05 0.50 BSC 2.38 ±0.05 (2 SIDES) RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS 1 0.25 ± 0.05 0.50 BSC 0.75 ±0.05 0.00 – 0.05 2.38 ±0.10 (2 SIDES) BOTTOM VIEW—EXPOSED PAD NOTE: 1. DRAWING TO BE MADE A JEDEC PACKAGE OUTLINE M0-229 VARIATION OF (WEED-2). CHECK THE LTC WEBSITE DATA SHEET FOR CURRENT STATUS OF VARIATION ASSIGNMENT 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 3472f 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. 11 LT3472 U TYPICAL APPLICATIO VIN 3V TO 4.2V 2.2µF 22µH SWP VPOS 15V 20mA 1µF 47µH VIN VPOS SWN DN 550k 47µH LT3472 FBP 4.7pF 320k FBN 10pF SHDN VNEG –8V 50mA SHDN SSP 2.2µF GND 100nF SSN 100nF 2.2µF 3472 TA03 RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LT1611 550mA (ISW), 1.4MHz, High Efficiency Micropower Inverting DC/DC Converter VIN: 1.1V to 10V, VOUT(MAX) = –34V, IQ = 3mA, ISD <1µA, ThinSOT Package LT1615/LT1615-1 300mA/80mA (ISW), High Efficiency Step-Up DC/DC Converter VIN: 1V to 15V, VOUT(MAX) = 34V, IQ = 20µA, ISD <1µA, ThinSOT Package LT1617/LT1617-1 350mA/100mA (ISW), High Efficiency Micropower Inverting DC/DC Converter VIN: 1.2V to 15V, VOUT(MAX) = –34V, IQ = 20µA, ISD <1µA, ThinSOT Package LT1930/LT1930A 1A (ISW), 1.2MHz/2.2MHz, High Efficiency Step-Up DC/DC Converter VIN: 2.6V to 16V, VOUT(MAX) = 34V, IQ = 4.2mA/5.5mA, ISD <1µA, ThinSOT Package LT1931/LT1931A 1A (ISW), 1.2MHz/2.2MHz, High Efficiency Micropower Inverting DC/DC Converter VIN: 2.6V to 16V, VOUT(MAX) = –34V, IQ = 5.8mA, ISD <1µA, ThinSOT Package LT1944/LT1944-1 Dual Output, 350mA/100mA (ISW), Constant Off-Time, High Efficiency Step-Up DC/DC Converter VIN: 1.2V to 15V, VOUT(MAX) = 34V, IQ = 20µA, ISD <1µA, MS10 Package LT1945(Dual) Dual Output, Boost/Inverter, 350mA (ISW), Constant Off-Time, High Efficiency Step-Up DC/DC Converter VIN: 1.2V to 15V, VOUT(MAX) = ±34V, IQ = 40µA, ISD <1µA, MS10 Package LT1946/LT1946A 1.5A (ISW), 1.2MHz/2.7MHz, High Efficiency Step-Up DC/DC Converter VIN: 2.45V to 16V, VOUT(MAX) = 34V, IQ = 3.2mA, ISD <1µA, MS8 Package LT3461/LT3461A 0.3A (ISW), Inverting 1.3MHz/3MHz High Efficiency Step-Up DC/DC Converter with Integrated Schottky Diodes VIN: 2.5V to 16V, VOUT(MAX) = 38V, IQ = 2.8mA, ISD <1µA, ThinSOT Package LT3462/LT3462A 300mA (ISW), Inverting 1.2MHz/2.7MHz DC/DC Converter with Integrated Schottky Diodes VIN: 2.5V to 16V, VOUT(MAX) = –38V, IQ = 2.9mA, ISD <10µA, ThinSOT Package LT3463/LT3463A Dual Output, Boost/Inverter, 250mA (ISW), Constant Off-Time, High Efficiency Step-Up DC/DC Converter with Integrated Schottkys VIN: 2.3V to 15V, VOUT(MAX) = 40V, IQ = 40µA, ISD <1µA, DFN Package LT3464 85mA (ISW), High Efficiency Step-Up DC/DC Converter with Integrated Schottky and PNP Disconnect VIN: 2.3V to 10V, VOUT(MAX) = 34V, IQ = 25µA, ISD <1µA, ThinSOT Package LT3467/LT3467A 1.1A, 1.3MHz/2.1MHz Step-Up DC/DC Converter with Integrated Soft-Start in ThinSOT VIN: 2.4V to 16V, VOUT(MAX) = 40V, IQ = 1mA, ISD <1µA, ThinSOT Package 3472f 12 Linear Technology Corporation LT/TP 0804 1K • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com © LINEAR TECHNOLOGY CORPORATION 2004