LT3467/LT3467A 1.1A Step-Up DC/DC Converter with Integrated Soft-Start FEATURES DESCRIPTION n 1.3MHz Switching Frequency (LT3467) The LT®3467/LT3467A switching regulators combine a n 2.1MHz Switching Frequency (LT3467A) 42V, 1.1A switch with a soft-start function. Pin compatible n Low V Switch: 330mV at 1.1A with the LT1930, its low V bipolar switch enables the CESAT CESAT n High Output Voltage: Up to 40V device to deliver high current outputs in a small footprint. n Wide Input Range: 2.4V to 16V The LT3467 switches at 1.3MHz, allowing the use of tiny, n Dedicated Soft-Start Pin low cost and low height inductors and capacitors. The n 5V at 540mA from 3.3V Input (LT3467) LT3467A switches at 2.1MHz, allowing the use of even n 5V at 430mA from 3.3V Input (LT3467A) smaller components. High inrush current at start-up is n 12V at 270mA from 5V Input (LT3467) eliminated using the programmable soft-start function. n 12V at 260mA from 5V Input (LT3467A) A single external capacitor sets the current ramp rate. A n Uses Small Surface Mount Components constant frequency current mode PWM architecture results n Low Shutdown Current: <1μA in low, predictable output noise that is easy to fi lter. n Pin-for-Pin Compatible with the LT1930 and LT1613 The high voltage switch on the LT3467/LT3467A is rated n Low Profi le (1mm) ThinSOT™ Package at 42V, making the devices ideal for boost converters up n Low Profi le (0.75mm) 8-Lead (3mm × 2mm) to 40V as well as SEPIC and fl yback designs. The LT3467 DFN Package can generate 5V at up to 540mA from a 3.3V supply or APPLICATIONS 5V at 450mA from four alkaline cells in a SEPIC design. The LT3467A can generate 5V at up to 430mA from a 3.3V n Digital Cameras supply or 15V at 135mA from a 3.3V supply. The LT3467/ n White LED Power Supplies LT3467A are available in a low profi le (1mm) 6-lead SOT-23 n Cellular Phones package and tiny 3mm × 2mm DFN package. n Medical Diagnostic Equipment L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear n Local 5V or 12V Supplies Technology Corporation. ThinSOT is a trademark of Linear Technology Corporation. All other trademarks are the property of their respective owners. n TFT-LCD Bias Supplies n xDSL Power Supplies TYPICAL APPLICATION Effi ciency 95 Single Li-Ion Cell to 5V Boost Converter 90 2.6V VTION 2.7μH V5VOUT 85 VIN = 3.3VVIN = 4.2V 4.2V 4.7μF 402k 765mA AT VIN = 4.2V, %) 80 VIN = 2.6V VIN SW 534600mmAA AATT VVIINN == 32..36VV, NCY ( 75 OFF ON SHDNLT3467 3.3pF FICIE 70 SS FB EF 65 0.047μF GND 133k 15μF 60 55 3467 TA01a 50 100 200 300 400 500 600 700 800 900 IOUT (mA) 3467 TA01b 3467afe 1

LT3467/LT3467A ABSOLUTE MAXIMUM RATINGS (Note 1) V Voltage ................................................................16V Operating Junction Temperature Range (Note 2) IN SW Voltage ................................................–0.4V to 42V E Grade ................................................–40°C to 85°C FB Voltage ................................................................2.5V I Grade ...............................................–40°C to 125°C Current Into FB Pin .............................................. ±1mA Storage Temperature Range ...................–65°C to 150°C SHDN Voltage ......................................................... 16V Lead Temperature (Soldering, 10 sec) Maximum Junction Temperature ......................... 125°C TSOT .................................................................300°C PIN CONFIGURATION TOP VIEW TOP VIEW FB 1 8 SHDN GND 2 7 SS SW 1 6 VIN 9 SW 3 6 VIN GND 2 5 SS SW 4 5 GND FB 3 4SHDN S6 PACKAGE DDB PACKAGE 6-LEAD PLASTIC TSOT-23 8-LEAD (3mm (cid:115) 2mm) PLASTIC DFN TJMAX = 125°C, θJA = 165°C/W, θJC = 102°C/W TJMAX = 125°C, θJA = 80°C/W EXPOSED PAD (PIN 9) IS GND, MUST BE SOLDERED TO PCB ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE LT3467EDDB#PBF LT3467EDDB#TRPBF LCPX 8-Lead (3mm × 2mm) Plastic DFN –40°C to 85°C LT3467IDDB#PBF LT3467IDDB#TRPBF LCPX 8-Lead (3mm × 2mm) Plastic DFN –40°C to 125°C LT3467AEDDB#PBF LT3467AEDDB#TRPBF LCKD 8-Lead (3mm × 2mm) Plastic DFN –40°C to 85°C LT3467AIDDB#PBF LT3467AIDDB#TRPBF LCKD 8-Lead (3mm × 2mm) Plastic DFN –40°C to 125°C LT3467IS6#PBF LT3467IS6#TRPBF LTACH 6-Lead Plastic TSOT-23 –40°C to 125°C LT3467ES6#PBF LT3467ES6#TRPBF LTACH 6-Lead Plastic TSOT-23 –40°C to 85°C LT3467AES6#PBF LT3467AES6#TRPBF LTBCC 6-Lead Plastic TSOT-23 –40°C to 85°C LT3467AIS6#PBF LT3467AIS6#TRPBF LTBCC 6-Lead Plastic TSOT-23 –40°C to 125°C LEAD BASED FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE LT3467EDDB LT3467EDDB#TR LCPX 8-Lead (3mm × 2mm) Plastic DFN –40°C to 85°C LT3467IDDB LT3467IDDB#TR LCPX 8-Lead (3mm × 2mm) Plastic DFN –40°C to 125°C LT3467AEDDB LT3467AEDDB#TR LCKD 8-Lead (3mm × 2mm) Plastic DFN –40°C to 85°C LT3467AIDDB LT3467AIDDB#TR LCKD 8-Lead (3mm × 2mm) Plastic DFN –40°C to 125°C LT3467IS6 LT3467IS6#TR LTACH 6-Lead Plastic TSOT-23 –40°C to 125°C LT3467ES6 LT3467ES6#TR LTACH 6-Lead Plastic TSOT-23 –40°C to 85°C LT3467AES67 LT3467AES6#TR LTBCC 6-Lead Plastic TSOT-23 –40°C to 85°C LT3467AIS67 LT3467AIS67#TR LTBCC 6-Lead Plastic TSOT-23 –40°C to 125°C Consult LTC Marketing for parts specifi ed with wider operating temperature ranges. *The temperature grade is identifi ed by a label on the shipping container. For more information on lead free part marking, go to: http://www.linear.com/leadfree/ For more information on tape and reel specifi cations, go to: http://www.linear.com/tapeandreel/ 3467afe 2

LT3467/LT3467A ELECTRICAL CHARACTERISTICS The l denotes the specifi cations which apply over the full operating temperature range, otherwise specifi cations are at T = 25°C. V = 3V, V = V unless otherwise noted. Specifi cations are for both A IN SHDN IN the LT3467 and LT3467A unless otherwise noted. PARAMETER CONDITIONS MIN TYP MAX UNITS Minimum Operating Voltage 2.2 2.4 V Maximum Operating Voltage 16 V Feedback Voltage 1.230 1.255 1.270 V l 1.220 1.280 V FB Pin Bias Current (Note 3) l 10 50 nA Quiescent Current V = 2.4V, Not Switching 1.2 2 mA SHDN Quiescent Current in Shutdown V = 0.5V, V = 3V 0.01 1 μA SHDN IN Reference Line Regulation 2.6V ≤ V ≤ 16V 0.01 0.05 %/V IN Switching Frequency LT3467 1 1.3 1.6 MHz LT3467A 1.6 2.1 2.7 MHz LT3467A l 1.6 MHz Maximum Duty Cycle LT3467 88 94 % LT3467 l 87 % LT3467A 82 88 % LT3467A l 78 % Minimum Duty Cycle 10 % Switch Current Limit At Minimum Duty Cycle 1.4 1.8 2.5 A At Maximum Duty Cycle (Note 4) 0.8 1.2 1.9 A Switch V I = 1.1A 330 500 mV CESAT SW Switch Leakage Current V = 5V 0.01 1 μA SW SHDN Input Voltage High 2.4 V SHDN Input Voltage Low 0.5 V SHDN Pin Bias Current V = 3V 16 32 μA SHDN V = 0V 0 0.1 μA SHDN SS Charging Current V = 0.5V 2 3 4.5 μA SS Note 1: Stresses beyond those listed under Absolute Maximum Ratings Note 3: Current fl ows out of the pin. may cause permanent damage to the device. Exposure to any Absolute Note 4: See Typical Performance Characteristics for guaranteed current Maximum Rating condition for extended periods may affect device limit vs duty cycle. reliability and lifetime. Note 2: The LT3467E/LT3467AE are guaranteed to meet performance specifi cations from 0°C to 85°C, junction temperature. Specifi cations over the –40°C to 85°C operating junction temperature range are assured by design, characterization and correlation with statistical process controls. The LT3467I/LT3467AI are guaranteed over the full –40°C to 125°C operating junction temperature range. 3467afe 3

LT3467/LT3467A TYPICAL PERFORMANCE CHARACTERISTICS Quiescent Current vs Temperature FB Pin Voltage vs Temperature SHDN Current vs SHDN Voltage 1.6 1.26 140 TA = 25°C 1.4 1.25 120 1.2 100 1.24 1.0 I(mA)Q 00..86 V(V)FB1.23 I (μA)SHDN 8600 1.22 40 0.4 1.21 0.2 20 0 1.20 0 –40–25–10 5 20 35 50 65 80 95110125 –40–25–10 5 20 35 50 65 80 95110125 0 2 4 6 8 10 12 14 16 18 TEMPERATURE (°C) TEMPERATURE (°C) VSHDN (V) 3467 G01 3467 G02 3467 G03 Switch Saturation Voltage Oscillator Frequency Current Limit vs Duty Cycle vs Switch Current vs Temperature 2.0 2.50 TA = 25°C 1.8 2.25 1.6 TYPICAL Hz)2.00 LT3467A M 1.4 TA = 25°C CY (1.75 N 1.2 E1.50 (A) M 1.0 GUARANTEED 100mVCVE/DSAIVT TA = 85°C REQU1.25 LT3467 ILI 0.8 TA = –40°C TOR F1.00 0.6 LA0.75 L 0.4 SCI0.50 O 0.2 0.25 0 0 10 20 30 40 50 60 70 80 90 SW CURRENT 200mA/DIV 3467 G05 –50 –25 0 25 50 75 100 DC (%) TEMPERATURE (°C) 3467 G04 3467 G06 Soft-Start Current Peak Switch Current Start-Up Waveform vs Soft-Start Voltage vs Soft-Start Voltage (Figure 2 Circuit) 6 2.0 TA = 25°C TA = 25°C 1.8 5 1.6 VSHDN 2V/DIV A) 1.4 4 T ( I (μA)SS 3 CH CURREN 110...208 1VV/ODUIVT 2 WIT 0.6 S 0.4 1 ISUPPLY 0.2 0.5A/DIV 0 0 0 50 100 150200 250300350400 450500 0 50 100 150200 250300350400 450500 0.5ms/DIV 3467 G09 VSS (mV) VSS (mV) 3467 G07 3467 G08 3467afe 4

LT3467/LT3467A PIN FUNCTIONS (DFN/TSOT) FB (Pin 1/Pin 3): Feedback Pin. Reference voltage is 1.255V. V (Pin 6/Pin 6): Input Supply Pin. Must be locally IN Connect resistive divider tap here. Minimize trace area at bypassed. FB. Set V = 1.255V(1 + R1/R2). OUT SS (Pin 7/Pin 5): Soft-Start Pin. Place a soft-start capacitor GND (Pins 2, 5, 9/Pin 2): Ground. Tie directly to local here. Upon start-up, 4μA of current charges the capacitor ground plane. to 1.255V. Use a larger capacitor for slower start-up. Leave fl oating if not in use. SW (Pins 3, 4/Pin 1): Switch Pin. (Collector of internal NPN power switch) Connect inductor/diode here and SHDN (Pin 8/Pin 4): Shutdown Pin. Tie to 2.4V or more minimize the metal trace area connected to this pin to to enable device. Ground to shut down. minimize EMI. BLOCK DIAGRAM 250k SS VIN RE1F.E2R5E5NVCE + COMPARATOR SW A1 – DRIVER – RC A2 R S Q Q1 VOUT CC + + R1 (EXTERNAL) FB (cid:51) 0.01Ω R2 (EXTERNAL) – RAMP GENERATOR SHUTDOWN SHDN FB GND 1.3MHz 3467 F01 OSCILLATOR* *2.1MHz FOR LT3467A Figure 1. Block Diagram 3467afe 5

LT3467/LT3467A OPERATION The LT3467 uses a constant frequency, current-mode con- for clean start-up conditions by limiting the rate of voltage trol scheme to provide excellent line and load regulation. rise at the output of comparator A1 which, in turn, limits Refer to the Block Diagram. At the start of each oscillator the peak switch current. The soft-start pin is connected cycle, the SR latch is set which turns on the power switch to a reference voltage of 1.255V through a 250k resistor, Q1. A voltage proportional to the switch current is added providing 4μA of current to charge the soft-start capacitor. to a stabilizing ramp and the resulting sum is fed into the Typical values for the soft-start capacitor range from 10nF positive terminal of the PWM comparator A2. When this to 200nF. The LT3467 has a current limit circuit not shown voltage exceeds the level at the negative input of A2, the in the Block Diagram. The switch current is constantly SR latch is reset, turning off the power switch. The level monitored and not allowed to exceed the maximum switch at the negative input of A2 is set by the error amplifi er A1, current (typically 1.4A). If the switch current reaches and is simply an amplifi ed version of the difference between this value, the SR latch is reset regardless of the state the feedback voltage and the reference voltage of 1.255V. of comparator A2. This current limit protects the power In this manner, the error amplifi er sets the correct peak switch as well as the external components connected to current level to keep the output in regulation. If the error the LT3467. amplifi er’s output increases, more current is delivered to The Block Diagram for the LT3467A (not shown) is identical the output. Similarly, if the error decreases, less current except that the oscillator frequency is 2.1MHz. is delivered. The soft-start feature of the LT3467 allows APPLICATIONS INFORMATION Duty Cycle Switching Frequency and Inductor Selection The typical maximum duty cycle of the LT3467 is 94% The LT3467 switches at 1.3 MHz, allowing for small valued (88% for the LT3467A). The duty cycle for a given ap- inductors to be used. 4.7μH or 10μH will usually suffi ce. plication is given by: The LT3467A switches at 2.1MHz, allowing for even smaller |V |+|V |–|V | valued inductors to be used. 0.9μH to 6.8μH will usually DC= OUT D IN suffi ce. Choose an inductor that can handle at least 1.2A |V |+|V |–|V | OUT D CESAT without saturating, and ensure that the inductor has a low DCR (copper-wire resistance) to minimize I2R power where V is the diode forward voltage drop and V is D CESAT losses. Note that in some applications, the current handling in the worst case 330mV (at 1.1A) requirements of the inductor can be lower, such as in the The LT3467 and LT3467A can be used at higher duty cycles, SEPIC topology where each inductor only carries one-half but must be operated in the discontinuous conduction of the total switch current. For better effi ciency, use similar mode so that the actual duty cycle is reduced. valued inductors with a larger volume. Many different sizes and shapes are available from various manufacturers. Setting Output Voltage Choose a core material that has low losses at 1.3MHz, (2.1MHz for the LT3467A) such as ferrite core. R1 and R2 determine the output voltage. V = 1.255V (1+ R1/R2) OUT 3467afe 6

LT3467/LT3467A APPLICATIONS INFORMATION L1 2.7μH D1 VIN VOUT 2.6V TO 4.2V 5V C1 R1 765mA AT VIN = 4.2V, 4.7μF VIN SW 402k 540mA AT VIN = 3.3V, 360mA AT VIN = 2.6V OFF ON SHDN C4 LT3467 3.3pF SS FB C2 C3 GND R2 15μF 0.047μF 133k C1, C2: X5R OR X7R, 6.3V 3467 TA05a D1: ON SEMICONDUCTOR MBRM120 L1: SUMIDA CR43-2R7 Figure 2. Single Li-Ion Cell to 5V Boost Converter (Same as 1st Page Application) Supply Current of Figure 2 During Start-Up Table 1. Inductor Manufacturers Without Soft-Start Capacitor Sumida (847) 956-0666 www.sumida.com TDK (847) 803-6100 www.tdk.com Murata (714) 852-2001 www.murata.com FDK (408) 432-8331 www.fdk.co.jp VOUT 1V/DIV Soft-Start The soft-start feature provides a way to limit the inrush current drawn from the supply upon start-up. An internal 250k resistor charges the external soft-start capacitor ISUPPLY to 1.255V. After the capacitor reaches 0.15V the rate of 0.5A/DIV voltage rise at the output of the comparator A1 tracks the 0.1ms/DIV 3467 AI01 rate of voltage rise of the soft-start capacitor. This limits the inrush current drawn from the supply during start- Supply Current of Figure 2 During Start-Up with a 47nF Soft-Start Capacitor up. The soft-start feature plays another important role in applications where the switch will reach levels of 30V or higher. During start-up, excessively high switch current, together with the presence of high voltage can overstress VOUT the switch. A properly used soft-start feature will keep the 1V/DIV switch current from overshooting. This practice will greatly improve the robustness of such designs. Once the part is shut down, the soft-start capacitor is quickly discharged to 0.4V, then slowly discharged through the 250k resistor to ground. If the part is to be shut down and re-enabled in ISUPPLY 0.5A/DIV a short period of time while soft-start is used, you must 0.5ms/DIV 3467 AI02 ensure that the soft-start capacitor has enough time to discharge before re-enabling the part. Typical values of the soft-start capacitor range from 10nF to 200nF. 3467afe 7

LT3467/LT3467A APPLICATIONS INFORMATION Capacitor Selection A phase lead zero can be intentionally introduced by placing a capacitor (C4) in parallel with the resistor (R1) between Low ESR (equivalent series resistance) capacitors should V and V as shown in Figure 2. The frequency of the be used at the output to minimize the output ripple voltage. OUT FB zero is determined by the following equation. Multi-layer ceramic capacitors are an excellent choice, as they have extremely low ESR and are available in very 1 ƒ = small packages. X5R dielectrics are preferred, followed Z 2π(cid:129)R1(cid:129)C4 by X7R, as these materials retain the capacitance over wide voltage and temperature ranges. A 4.7μF to 15μF By choosing the appropriate values for the resistor and output capacitor is suffi cient for most applications, but capacitor, the zero frequency can be designed to improve systems with very low output currents may need only a the phase margin of the overall converter. The typical 1μF or 2.2μF output capacitor. Solid tantalum or OS-CON target value for the zero frequency is between 35kHz capacitors can be used, but they will occupy more board to 55kHz. Figure 3 shows the transient response of the area than a ceramic and will have a higher ESR. Always step-up converter from Figure 8 without the phase lead use a capacitor with a suffi cient voltage rating. capacitor C4. Although adequate for many applications, phase margin is not ideal as evidenced by 2-3 “bumps” Ceramic capacitors also make a good choice for the input in both the output voltage and inductor current. A 22pF decoupling capacitor, which should be placed as close as capacitor for C4 results in ideal phase margin, which is possible to the LT3467. A 1μF to 4.7μF input capacitor revealed in Figure 4 as a more damped response and less is suffi cient for most applications. Table 2 shows a list overshoot. of several ceramic capacitor manufacturers. Consult the manufacturers for detailed information on their entire Diode Selection selection of ceramic parts. A Schottky diode is recommended for use with the LT3467 Table 2. Ceramic Capacitor Manufacturers and the LT3467A. The Philips PMEG 2005 is a very good Taiyo Yuden (408) 573-4150 www.t-yuden.com choice. Where the switch voltage exceeds 20V, use the AVX (803) 448-9411 www.avxcorp.com PMEG 3005 (a 30V diode). Where the switch voltage Murata (714) 852-2001 www.murata.com exceeds 30V, use the PMEG 4005 (a 40V diode). These diodes are rated to handle an average forward current of The decision to use either low ESR (ceramic) capacitors 0.5A. In applications where the average forward current or the higher ESR (tantalum or OS-CON) capacitors can of the diode exceeds 0.5A, a Philips PMEG 2010 rated at affect the stability of the overall system. The ESR of any 1A is recommended. For higher effi ciency, use a diode capacitor, along with the capacitance itself, contributes with better thermal characteristics such as the On Semi- a zero to the system. For the tantalum and OS-CON ca- conductor MBRM120 (a 20V diode) or the MBRM140 (a pacitors, this zero is located at a lower frequency due to 40V diode). the higher value of the ESR, while the zero of a ceramic capacitor is at a much higher frequency and can generally be ignored. 3467afe 8

LT3467/LT3467A APPLICATIONS INFORMATION Layout Hints LOAD CURRENT 100mA/DIV AC COUPLED The high speed operation of the LT3467/LT3467A demands careful attention to board layout. You will not get adver- VOUT tised performance with careless layout. Figure 5a shows 200mV/DIV AC COUPLED the recommended component placement for the ThinSOT package. Figure 5b shows the recommended component placement for the DFN package. Note the vias under the IL1 5A/DIV Exposed Pad. These should connect to a local ground AC COUPLED plane for better thermal performance. 20μs/DIV 3467 F03 Figure 3. Transient Response of Figure 8’s Step-Up Converter without Phase Lead Capacitor L1 D1 C1 VOUT VIN LOAD CURRENT 100mA/DIV C2 1 6 AC COUPLED CSS 2 5 SS VOUT GND 3 4 SHDN 200mV/DIV FB AC COUPLED R2 R1 IL1 5A/DIV C3 VOUT 3467 F05a AC COUPLED 20μs/DIV 3467 F04 Figure 5a. Suggested Layout—ThinSOT Figure 4. Transient Response of Figure 8’s Step-Up Converter with a 22pF Phase Lead Capacitor VOUT C3 Setting Output Voltage R1 To set the output voltage, select the values of R1 and R2 R2 (see Figure 2) according to the following equation. SHDN GND FB 1 8 R1=R2⎛⎜ VOUT –1⎞⎟ 2 7 CSS ⎝1.255V ⎠ C2 3 6 VOUT 4 5 VIN A good value for R2 is 13.3k which sets the current in the D1 C1 resistor divider chain to 1.255V/13.3k = 94μA. L1 3467 F05b Figure 5b. Suggested Layout—DFN 3467afe 9

LT3467/LT3467A APPLICATIONS INFORMATION Compensation—Theory From Figure 6, the DC gain, poles and zeroes can be calculated as follows: Like all other current mode switching regulators, the LT3467/LT3467A needs to be compensated for stable 2 Output Pole: P1= and effi cient operation. Two feedback loops are used in 2(cid:129)π(cid:129)R (cid:129)C L OUT the LT3467/LT3467A: a fast current loop which does not 1 require compensation, and a slower voltage loop which Error Amp Pole: P2= 2(cid:129)π(cid:129)R (cid:129)C does. Standard Bode plot analysis can be used to under- O C stand and adjust the voltage feedback loop. 1 Error Amp Zero: Z1= As with any feedback loop, identifying the gain and phase 2(cid:129)π(cid:129)R (cid:129)C C C contribution of the various elements in the loop is critical. 1.255 1 DC GAIN: A= (cid:129)V (cid:129)g (cid:129)R (cid:129)g (cid:129)R (cid:129) Figure 6 shows the key equivalent elements of a boost V 2 IN ma O mp L 2 converter. Because of the fast current control loop, the OUT power stage of the IC, inductor and diode have been re- 1 ESR Zero: Z2= placed by the equivalent transconductance amplifi er gmp. 2(cid:129)π(cid:129)RESR (cid:129)COUT g acts as a current source where the output current is mp 2 V (cid:129)R proportional to the VC voltage. Note that the maximum RHP Zero: Z3= IN L output current of gmp is fi nite due to the current limit 2(cid:129)π(cid:129)V 2 (cid:129)L OUT in the IC. f High Frequency Pole: P3> S 3 – 1 PhaseLeadZero:Z4= gmp VOUT 2(cid:129)π(cid:129)R1(cid:129)C + CPL RESR RL PL 1 + 1.255V COUT PhaseLeadPole:P4= R1(cid:129)R2 VC REFERENCE 2(cid:129)π(cid:129)C (cid:129) gma R1 PL R1+R2 RC RO – CC R2 The current mode zero is a right-half plane zero which can 3467 F06 be an issue in feedback control design, but is manageable CC: COMPENSATION CAPACITOR with proper external component selection. 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 3467afe 10

LT3467/LT3467A APPLICATIONS INFORMATION Using the circuit of Figure 2 as an example, the following Table 3. Bode Plot Parameters table shows the parameters used to generate the Bode PARAMETER VALUE UNITS COMMENT plot shown in Figure 7. R 10.4 Ω Application Specifi c L C 15 μF Application Specifi c 50 0 OUT R 10 mΩ Application Specifi c 40 –45 ESR R 0.4 MΩ Not Adjustable 30 –90 O 20 –135 CC 60 pF Not Adjustable GAIN (dB)–11000 –––122827050PHASE (DEG CRRP1CL 14300.302 kkpΩΩF ANAddojjtuu Assdttaajubbslleetable ) –20 –315 R2 133 kΩ Adjustable –30 –360 V 5 V Application Specifi c OUT –40 GAIN –405 PHASE VIN 3.3 V Application Specifi c –50 –450 100 1k 10k 100k 1M g 35 μmho Not Adjustable ma FREQUENCY (Hz) g 7.5 mho Not Adjustable mp 3467 F07 L 2.7 μH Application Specifi c Figure 7. Bode Plot of 3.3V to 5V Application f 1.3* MHz Not Adjustable S *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 Li-Ion to 6V L1 95 2.2μH D1 VIN VOUT 90 VIN = 4.2V 2.7V TO 4.2V 6V R1 275mA AT VIN = 2.7V 85 VIN = 3.8V C1 SHDN SVHIDNN SW 501k C3 459900mmAA AATT VVIINN == 34..82VV %) 80 VIN = 2.7V 2.2μF LT3467 1.8pF CY ( 75 SS FB CIEN 70 C4 GND R2 C2 FI 0.047μF 133k 15μF EF 65 60 C1, C2: X5R OR X7R, 6.3V D1: ON SEMICONDUCTOR MBRM120 3467 TA02 55 L1: SUMIDA CR43-2R2 50 50100 200 300 400 500 600 700 IOUT (mA) 3467 TA02b 3467afe 11

LT3467/LT3467A TYPICAL APPLICATIONS 4-Cell to 5V SEPIC Converter C3 L1 4V TO 6.5V 10μH 1μF D1 VOUT 5V C2.12μF VIN SW 342050mmAA AATT VVIINN == 45VV SHDN SHDN 255k C5 450mA AT VIN = 6.5V BA4T-TCEERLYL LT3467 4.7pF L2 C2 SS FB 10μH 10μF C4 GND 84.5k 0.047μF C1, C3: X5R or X7R, 10V D1: PHILIPS PMEG 2010 C2: X5R or X7R, 6.3V L1, L2: MURATA LQH32CN100K33L 3467 TA03 5V to 40V Boost Converter L1 VIN 2.7μH D1 V40OVUT 5V C1 20mA 4.7μF VIN SW R1 SHDN SHDN 412k LT3467 C2 1μF SS FB C3 GND R2 0.1μF 13.3k C1: X5R or X7R, 6.3V 3467 TA04a C2: X5R or X7R, 50V D1: ON SEMICONDUCTOR, MBRM140 L1: SUMIDA CD43-2R7 ±15V Dual Output Converter with Output Disconnect C4 L1 10μH 1μF D1 VIN 15V 5V 100mA C1 2.2μF R3 R1 VIN SW C5 1Ω 147k 1μF OFF ON SHDN LT3467 D2 C2 2.2μF SS FB C6 GND R2 0.047μF 13.3k CCD121: TTXOO5 RCD 54o::r X PX5H7RIRL o,I Pr6 S.X3 7PVRM, E1G6 V2005 D31RΩ4 D4 C2.32μF –15V L1: SUMIDA CR43-100 3467 TA05 100mA 3467afe 12

LT3467/LT3467A TYPICAL APPLICATIONS 9V, 18V, –9V Triple Output TFT-LCD Bias Supply with Soft-Start D1 D2 18V C4 10mA C3 1μF 0.1μF Start-Up Waveforms L1 D5 4.7μH VIN 9V 9V OUTPUT 3.3V 220mA 5V/DIV C1 –9V OUTPUT 2.2μF VIN SW R1 5V/DIV VSHDN SHDN 124k LT3467 C5 SS FB 10μF 3.3V GND R2 0V 18V OUTPUT C7 C2 20k 10V/DIV 0.1μF 0.1μF C1: X5R OR X7R, 6.3V D4 IL1 C2,C3, C5, C6: X5R OR X7R, 10V 0.5A/DIV C4: X5R OR X7R, 25V 2ms/DIV 3467 TA06b C6 D1 TO D4: PHILIPS BAT54S OR EQUIVALENT D3 1μF D5: PHILIPS PMEG 2005 –9V L1: PANASONIC ELT5KT4R7M 10mA 3467 TA06a 8V, 23V, –8V Triple Output TFT-LCD Bias Supply with Soft-Start D1 D2 D3 D4 23V 10mA C3 C4 C5 C6 0.1μF 0.1μF 0.1μF 1μF Start-Up Waveforms L1 4.7μH D7 VIN 8V 8V OUTPUT 3.3V 270mA 5V/DIV C1 –8V OUTPUT 2.2μF VIN SW R1113k 5V/DIV VSHDN SHDN LT3467 C7 SS FB 10μF 3.3V GND 0V R2 23V OUTPUT C9 C2 21k 10V/DIV 0.1μF 0.1μF C1: X5R OR X7R, 6.3V IL1 C2 TO C4, C7, C8: X5R OR X7R, 10V D5 0.5A/DIV C5: X5R OR X7R, 16V 2ms/DIV 3467 TA07b C6: X5R OR X7R, 25V C8 D6 D1 TO D6: PHILIPS BAT54S OR EQUIVALENT 1μF D7: PHILIPS PMEG 2005 –8V L1: PANASONIC ELT5KT4R7M 3467 TA07a 10mA 3467afe 13

LT3467/LT3467A TYPICAL APPLICATIONS Single Li-Ion Cell to 5V Boost Converter Effi ciency L1 95 0.9μH D1 VIN VOUT 90 2.6V TO 4.2V 5V R1 600mA AT VIN = 4.2V 85 C1 VIN SW 8.06k 360mA AT VIN = 3.3V VIN = 4.2V 4.7μF OFF ON SHDN C4* 250mA AT VIN = 2.6V %) 80 VIN = 3.3V LT3467A 75pF CY ( 75 VIN = 2.6V SS FB N E C3 GND R2 C2* FICI 70 0.047μF 2.67k 22μF EF 65 60 C1, C2: X5R OR X7R, 6.3V 3467 TA09a D1: PHILIPS PMEG 2010 55 L1: FDK MIPW3226D0R9M *C2 CAN BE 10μF IN A 1210 OR LARGER PACKAGE WITH 50 THE ADDITION OF C4, OTHERWISE C4 IS OPTIONAL 50 100 150 200 250 300 350 400 450 500 IOUT (mA) 3467 TA09b 2.6V-3.3V to 5V Boost Converter Effi ciency L1 90 1.5μH D1 VIN VOUT 85 2.6V TO 3.3V 5V 4.7Cμ1F OFF ON SVHIDNN SW 8.0R61k C4 423700mmAA AATT VVIINN == 32..36VV %) 8705 VIN = 2.6V VIN = 3.3V LT3467A 56pF CY ( SS FB EN 70 CI 0.047Cμ3F GND 2.6R72k C102μF EFFI 65 60 C1, C2: X5R OR X7R, 6.3V D1: PHILIPS PMEG 2010 3467 TA08a 55 L1: FDK MIP3226D1R5M 50 50 100 150 200 250 300 350 400 450 500 IOUT (mA) 3467 TA08b 3.3V to 15V, 135mA Step-Up Converter Effi ciency L1 90 VIN 6.8μH D1 VOUT 3.3V 15V 80 135mA R1 C1 VIN SW 16.5k 4.7μF OFF ON SHDNLT3467A C684pF CY (%) 70 SS FB EN 60 CI C3 GND R2 C2 FFI 0.047μF 1.5k 2.2μF E 50 C1: X5R OR X7R, 6.3V 40 3467 TA10a C2: X5R OR X7R, 16V D1: PHILIPS PMEG 2010 L1: SUMIDA CMD4D13-6R8MC 30 20 40 60 80 100 120 140 160 IOUT (mA) 3467 TA10b 3467afe 14

LT3467/LT3467A PACKAGE DESCRIPTION DDB Package 8-Lead Plastic DFN (3mm × 2mm) (Reference LTC DWG # 05-08-1702 Rev B) 0.61(cid:112)0.05 3.00(cid:112)0.10 R = 0.115 0.40(cid:112) 0.10 (2 SIDES) R = 0.05 TYP (2 SIDES) TYP 5 8 0.70(cid:112)0.05 2.55(cid:112)0.05 2.00(cid:112)0.10 1.15(cid:112)0.05 PIN 1 BAR (2 SIDES) PIN 1 TOP MARK R = 0.20 OR PACKAGE (SEE NOTE 6) 0.56(cid:112) 0.05 0.25(cid:115) 45(cid:111) OUTLINE (2 SIDES) 4 1 CHAMFER 0.25(cid:112) 0.05 0.200 REF 0.75(cid:112)0.05 0.25(cid:112) 0.05 (DDB8) DFN 0905 REV B 0.50 BSC 0.50 BSC 2.20(cid:112)0.05 2.15(cid:112)0.05 (2 SIDES) (2 SIDES) 0 – 0.05 RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS BOTTOM VIEW—EXPOSED PAD 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 3467afe 15

LT3467/LT3467A PACKAGE DESCRIPTION S6 Package 6-Lead Plastic TSOT-23 (Reference LTC DWG # 05-08-1636) 0.62 0.95 2.90 BSC MAX REF (NOTE 4) 1.22 REF 3.85 MAX 2.62 REF 1.4 MIN 2.80 BSC 1(.5N0O T–E 1 4.7)5 PIN ONE ID RECOMMENDED SOLDER PAD LAYOUT 0.30 – 0.45 0.95 BSC PER IPC CALCULATOR 6 PLCS (NOTE 3) 0.80 – 0.90 0.20 BSC 0.01 – 0.10 1.00 MAX DATUM ‘A’ 0.30 – 0.50 REF 0.09 – 0.20 1.90 BSC (NOTE 3) S6 TSOT-23 1005 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 3467afe 16

LT3467/LT3467A REVISION HISTORY (Revision history begins at Rev E) REV DATE DESCRIPTION PAGE NUMBER E 04/10 Updated Note 2 in Absolute Maximum Ratings and Electrical Characteristics 2, 3 3467afe Information furnished by Linear Technology Corporation is believed to be accurate and reliable. 17 However, no responsibility is assumed for its use. Linear Technology Corporation makes no representa- tion that the interconnection of its circuits as described herein will not infringe on existing patent rights.

LT3467/LT3467A TYPICAL APPLICATIONS L1 Effi ciency VIN 4.7μH D1 V12OVUT 90 5V C1 270mA 2.2μF R1 85 VIN SW 115k C4* 80 SHDN SHDN 22pF SS LT3467 FB C102μF Y (%) 75 C 0.047Cμ3F GND R132.3k CIEN 70 EFFI 65 CC12:: XX55RR OORR XX77RR,, 61.63VV 3467 F08a 60 D1: PHILIPS PMEG 2010 55 L1: SUMIDA CR43-4R7 *OPTIONAL 50 50 100 150 200 250 300 350 Figure 8. 5V to 12V, 270mA Step-Up Converter IOUT (mA) 3467 F08b Effi ciency L1 V5IVN 3.3μH D1 V12OVUT 95 R1 260mA 90 C1 VIN SW 115k 85 4.7μF OFF ON SHDN C4 LT3467A 12pF %) 80 SS FB Y ( 75 0.047Cμ3F GND 13.R32k C102μF CIENC 70 EFFI 65 C1: X5R OR X7R, 6.3V C2: X5R OR X7R, 16V 3467 F09a 60 D1: PHILIPS PMEG 2010 L1: SUMIDA CDRH4D18-3R3 55 50 Figure 9. 5V to 12V, 260mA Step-Up Converter 50 100 150 200 250 300 IOUT (mA) 3467 F09b RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LT1615/LT1615-1 300mA/80mA (I ), High Effi ciency Step-Up DC/DC Converter V : 1V to 15V, V = 34V, I = 20μA, I < 1μA, SW IN OUT(MAX) Q SD ThinSOT Package LT1618 1.5A (I ), 1.25MHz, High Effi ciency Step-Up DC/DC Converter 90% Effi ciency, V : 1.6V to 18V, V = 35V, I = 1.8mA, SW IN OUT(MAX) Q I < 1μA, MS Package SD LTC1700 No R ™, 530kHz, Synchronous Step-Up DC/DC Controller 95% Effi ciency, V : 0.9V to 5V, IQ = 200μA, I < 10μA, SENSE IN SD MS Package LTC1871 Wide Input Range, 1MHz, No R Current Mode Boost, 92% Effi ciency, V : 2.5V to 36V, I = 250μA, I < 10μA, SENSE IN Q SD Flyback and SEPIC Controller MS Package LT1930/LT1930A 1A (I ), 1.2MHz/2.2MHz, High Effi ciency Step-Up High Effi ciency, V : 2.6V to 16V, V = 34V, SW IN OUT(MAX) DC/DC Converter I = 4.2mA/5.5mA, I < 1μA, ThinSOT Package Q SD LT1946/LT1946A 1.5A (I ), 1.2MHz/2.7MHz, High Effi ciency Step-Up High Effi ciency, V : 2.45V to 16V, V = 34V, I = 3.2mA, SW IN OUT(MAX) Q DC/DC Converter with Soft-Start I < 1μA, MS8 Package SD LT1961 1.5A (I ), 1.25MHz, High Effi ciency Step-Up DC/DC Converter 90% Effi ciency, V : 3V to 25V, V = 35V, I = 0.9mA, SW IN OUT(MAX) Q I < 6μA, MS8E Package SD LTC3400/ 600mA (I ), 1.2MHz, Synchronous Step-Up DC/DC Converter 92% Effi ciency, V : 0.85V to 5V, V = 5V, SW IN OUT(MAX) LTC3400B I = 19μA/300μA, I < 1μA, ThinSOT Package Q SD LTC3401 1A (I ), 3MHz, Synchronous Step-Up DC/DC Converter 97% Effi ciency, V : 0.5V to 5V, V = 5.5V, I = 38μA, SW IN OUT(MAX) Q I < 1μA, MS Package SD LTC3402 2A (I ), 3MHz, Synchronous Step-Up DC/DC Converter 97% Effi ciency, V : 0.5V to 5V, V = 5.5V, I = 38μA, SW IN OUT(MAX) Q I < 1μA, MS Package SD LT3464 85mA (I ), High Effi ciency Step-Up DC/DC Converter with V : 2.3V to 10V, V = 34V, I = 25μA, I < 1μA, SW IN OUT(MAX) Q SD Integrated Schottky and PNP Disconnect ThinSOT Package No R is a trademark of Linear Technology Corporation. SENSE 3467afe 18 Linear Technology Corporation LT 0410 REV E • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com © LINEAR TECHNOLOGY CORPORATION 2003

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