LT3464 Micropower Boost Converter with Schottky and Output Disconnect in ThinSOT™ U DESCRIPTIO FEATURES ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ ■ The LT®3464 is a micropower step-up DC/DC converter with integrated Schottky diode and output disconnect packaged in an 8-lead low profile (1mm) SOT-23. The small package size, high level of integration, and the use of tiny SMT components yield a solution size of less than 40mm2. The LT3464 has a typical current limit of 115mA as well as fast switching speed to allow the use of a chip inductor and small ceramic capacitors. The internal PNP disconnects the output load from the input during shutdown, and also provides output short-circuit protection. An auxiliary reference input allows the user to override the internal 1.25V feedback reference with any lower value, allowing full control of the output voltage during operation. This device features a low 25 µA quiescent current, which is further reduced to less than 0.5µA in shutdown. A current limited fixed off-time control scheme conserves operating current, resulting in high efficiency over a broad range of operating current. The rugged 36V switch and output disconnect circuitry allow outputs up to 34V to be easily generated in a simple boost topology. Tiny Solution Size Low Quiescent Current • 25µA in Active Mode • 0.5µA in Shutdown Mode Internal 115mA, 36V Switch Integrated Schottky Diode Integrated PNP Output Disconnect with Short-Circuit Protection Internal Reference Override Pin 16V at 8mA from 3.6V Input 12V at 20mA from 5V Input Input Range: 2.3V to 10V High Output Voltage: Up to 34V Low Profile (1mm) SOT-23 Package U APPLICATIO S ■ ■ ■ ■ ■ OEL Panel Bias LCD Bias Handheld Computers Battery Backup Digital Cameras Cellular Phones , LTC and LT are registered trademarks of Linear Technology Corporation. ThinSOT is a trademark of Linear Technolgy Corporation U ■ TYPICAL APPLICATIO Efficiency 22µH VIN 90 80 SW VOUT 16V OUT 1µF 0.22µF CTRL LT3464 CAP 0.33µF SHDN 3.48M FB GND 294k 3464 TA01a VIN = 8.4V VIN = 4.2V EFFICIENCY (%) VIN 2.3V TO 10V 70 60 50 40 30 0.01 0.1 1 10 LOAD CURRENT (mA) 100 3464 TA01b 3464f 1 LT3464 U W W W ABSOLUTE AXI U RATI GS U W U PACKAGE/ORDER I FOR ATIO (Note 1) VIN, SHDN, CTRL Voltage ........................................ 10V OUT, CAP Voltage .................................................... 36V SW Voltage .............................................................. 36V FB Voltage ................................................................. 6V Maximum Junction Temperature .......................... 125°C Operating Temperature Range (Note 2) .. – 40°C to 85°C Storage Temperature Range ..................–65°C to 150°C Lead Temperature (Soldering, 10 sec).................. 300°C ORDER PART NUMBER TOP VIEW CTRL 1 FB 2 OUT 3 GND 4 8 SHDN 7 VIN 6 SW 5 CAP LT3464ETS8 TS8 PART MARKING TS8 PACKAGE 8-LEAD PLASTIC SOT-23 LTG2 TJMAX = 125°C, θJA = 140°C/W, θJC = 85°C/W 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 = 3.6V, unless otherwise noted. (Note 2) PARAMETER CONDITIONS MIN Minimum Input Voltage Quiescent Current Not Switching VSHDN = 0.2V FB Comparator Trip Voltage VFB Falling, VCTRL = 3.6V ● 1.215 FB Comparator Hysteresis TYP MAX UNITS 2.0 2.3 V 25 0.01 36 0.5 µA µA 1.250 1.275 V 10 mV FB Pin Bias Current VFB = 1.25V, VCTRL = 3.6V 3 30 nA FB Voltage Line Regulation 2.3V < VIN < 10V 0.05 0.1 %/V Switch Off Time VCAP-VIN = 5V VCAP-VIN = 0V 250 1.0 Switch Leakage Current VSW = 36V 0.02 1 µA Switch VCESAT ISW = 80mA 190 300 mV 115 140 mA ● Switch Current Limit 85 ns µs Schottky Forward Voltage ISCHOTTKY = 110mA 600 750 mV Schottky Reverse Leakage VCAP-SW = 36V 1 10 µA PNP Disconnect VCAP-OUT IOUT = 200µA IOUT = 10mA 100 190 PNP Disconnect Q Current IOUT = 0, VCAP = 36V (Note 3) 1.5 5 µA PNP Disconnect Leakage SHDN = 0.2, VCAP = 10V, VOUT = 0V 0.1 5 µA 45 75 mA 5 10 µA PNP Disconnect Current Limit VCAP = 10V, VOUT = 0V SHDN Pin Current VSHDN = 3.6V 25 SHDN Input Voltage High mV mV 2.3 V SHDN Input Voltage Low CTRL Pin Bias Current VCTRL = 0.5V, VFB = 1V CTRL to FB Offset VCTRL = 0.5V (Note 4) Note 1: Absolute Maximum Ratings are those values beyond which the life of a device may be impaired. Note 2: The LT3464E is guaranteed to meet performance specifications from 0°C to 70°C. Specifications over the – 40°C to 85°C operating temperature range are assured by design, characterization and correlation with statistical process controls. ● 0.2 V 6 80 nA 2 7 mV Note 3: Current consumed by Disconnect PNP when there is no load on the OUT pin. Note 4: This figure is computed according to ((VFB falling + VFB rising)/2) –VCONTROL. 3464f 2 LT3464 U W TYPICAL PERFOR A CE CHARACTERISTICS Switch Off-Time, VCAP – VIN = 5V Switch Current Limit 220 140 400 200 120 350 180 160 140 120 100 SWITCH OFF-TIME (ns) SWITCH CURRENT (mA) SWITCH VOLTAGE (mV) Switch Saturation Voltage ISW = 80mA 80 60 40 20 100 –50 –25 0 25 50 TEMPERATURE (°C) 75 –25 0 25 50 TEMPERATURE (°C) 75 3464 G01 Minimum Switch On-Time 60 50 40 30 20 75 250 1.1 1.0 0.9 0.8 0.7 IOUT = 10mA 200 150 IOUT = 200µA 100 50 0.5 –50 100 –25 0 25 50 TEMPERATURE (°C) 75 0 –50 100 –25 0 25 50 TEMPERATURE (°C) 100 Output Disconnect Voltage Drop Output Disconnect Current Limit 2.0 75 3464 G06 3464 G05 3464 G04 Output Disconnect Quiescent Current 100 Output Disconnect Voltage Drop 0.6 10 75 0 25 50 TEMPERATURE (°C) 300 VOLTAGE DROP (mV) SWITCH OFF-TIME (µs) 70 –25 3464 G03 1.2 80 SWITCH ON-TIME (ns) 100 Switch Off-Time, VCAP – VIN = 0V 90 0 25 50 TEMPERATURE (°C) 150 0 –50 100 1.3 –25 200 3464 G02 100 0 –50 250 50 0 –50 100 300 60 300 50 250 1.4 1.2 1.0 0.8 0.6 0.4 40 30 20 10 0.2 0 –50 VOLTAGE DROP (mV) 1.6 CURRENT LIMIT (mA) QUIESCENT CURRENT (µA) 1.8 –25 0 25 50 TEMPERATURE (°C) 75 100 3464 G07 0 –50 200 150 100 50 –25 0 25 50 TEMPERATURE (°C) 75 100 3464 G08 0 0 10 20 COLLECTOR CURRENT (mA) 30 3464 G09 3464f 3 LT3464 U W TYPICAL PERFOR A CE CHARACTERISTICS Schottky Forward Drop at ID = 110mA Schottky Reverse Leakage Schottky Forward Voltage 800 250 20 200 16 SCHOTTKY CURRENT (mA) VOLTAGE DROP (mV) 700 650 600 550 500 450 400 LEAKAGE CURRENT (µA) 750 150 100 50 VCAP – SW = 36V 12 8 4 350 300 –50 –25 0 25 50 TEMPERATURE (°C) 75 0 200 100 300 400 500 600 700 FORWARD VOLTAGE (mV) 0 –50 800 30 12 16 18 16 14 12 10 –50 –25 0 25 50 TEMPERATURE (°C) 75 14 10 QUIESCENT CURRENT (nA) SHUTDOWN PIN CURRENT (µA) QUIESCENT CURRENT (µA) 20 8 6 4 2 –25 0 25 50 TEMPERATURE (°C) 75 Quiescent Current in Regulation with No Load 8 6 4 0 –50 100 –25 0 25 50 TEMPERATURE (°C) 75 100 3464 G14 FB Pin Voltage SHDN Pin Threshold Voltage 70 1.30 3.0 2.8 60 1.28 2.6 50 40 30 20 2.4 FB PIN VOLTAGE (V) SHDN PIN VOLTAGE (V) QUIESCENT CURRENT (µA) 10 3464 G13 3464 G12 2.2 2.0 1.8 1.6 VIN = 5V FRONT PAGE SCHEMATIC 6 8 10 14 12 VOUT (V) 1.26 1.24 1.22 1.4 10 0 12 2 0 –50 100 100 Quiescent Current in Shutdown Mode 28 22 75 3464 G20 Shutdown Pin Current VSHDN = 3.6V Quiescent Current 24 0 25 50 TEMPERATURE (°C) 3464 G11 3464 G10 26 –25 1.2 16 18 20 3464 G18 1.0 –50 –25 0 25 50 TEMPERATURE (°C) 75 100 3464 G15 1.20 –50 –25 0 25 50 TEMPERATURE (°C) 75 100 3464 G16 3464f 4 LT3464 U W TYPICAL PERFOR A CE CHARACTERISTICS FB Pin Voltage vs CTRL Pin Voltage FB and CTRL Pin Bias Currents 1.50 8 7 1.00 0.75 0.50 10 CTRL PIN 6 HYSTERESIS (mV) BIAS CURRENT (nA) 1.25 FB PIN VOLTAGE (V) FB Pin Hysteresis 12 5 4 FEEDBACK PIN 3 8 6 4 2 0.25 0 2 1 0 0.25 0.5 0.75 1.0 1.25 1.5 CONTROL PIN VOLTAGE (V) 1.75 0 –50 –25 0 25 50 TEMPERATURE (°C) 3464 G17 75 100 3464 G18 0 –50 –25 0 25 50 TEMPERATURE (°C) 75 100 3464 G19 U U U PI FU CTIO S CTRL (Pin 1): Internal Reference Override Pin. This allows the FB voltage to be externally set between 0V and 1.25V. Tie this pin to above 1.5V (V IN for example) to use the internal 1.25V reference. R2 VOUT = VCTRL + 1 R1 when VCTRL is less than 1.25V (see Figure 4) FB (Pin 2): Feedback Pin. The LT3464 regulates its feedback pin to 1.25V if the internal reference is used or to VCTRL if the CTRL pin is between 0V and 1.25V. Connect the feedback resistor divider tap to this pin. Set the output voltage by selecting R1 and R2 (see Figure 4). V R2 = R1 OUT – 1 VREF GND (Pin 4): Ground. Tie this pin directly to the ground plane. CAP (Pin 5): PNP Emitter and Schottky Cathode. This pin connects to the output capacitor, and optionally to the external phase-lead capacitor. SW (Pin 6): Switch Pin and Schottky Anode. This is the collector of the internal NPN power switch. Minimize the metal trace area connected to the pin to minimize EMI. VIN (Pin 7): Input Supply Pin: Bypass this pin with a capacitor located as close to the device as possible. SHDN (Pin 8): Shutdown Pin. This pin is used to put the device in shutdown mode. Tie the pin low to shut down the LT3464. Tie high for normal operation See the electrical specifications for the required voltages. OUT (Pin 3): PNP Collector. This is the output of the Output Disconnect circuit. Bypass this pin with at least a 0.1µF capacitor connected to the CAP pin or to ground. 3464f 5 LT3464 W BLOCK DIAGRA VIN SW CAP OUT 7 6 5 3 DELAY CPL FB CTRL 2 1 + – – S Q R Q OUT ANTI SAT + 1.25V OUT 12mV – SHDN 8 0.1Ω VREF 4 GND 3464 BD U OPERATIO The LT3464 uses a constant off-time control scheme in conjunction with Burst Mode ® operation to provide high efficiency over a wide range of output current. Operation can best be understood by studying the Block Diagram. When the FB pin voltage is lower than the 1.25V reference, the hysteretic comparator enables the power section, causing the chip to start switching, thus charging the output capacitor. When the output voltage increases enough to overcome the hysteresis, the feedback comparator shuts off the power section leaving only low power circuitry running until the output voltage falls again. This cycle repeats, keeping the output voltage within a small window. The switching action is as follows: The switch turns on, and current through it starts to ramp up until the point where the current limit is reached, at which point the switch turns off for a fixed amount of time. While the switch is off the inductor is delivering current to the load. When the off time expires, the switch turns on again until the current limit is reached, and the cycle repeats. This chip includes an internal power Schottky diode and a PNP transistor for output disconnect. The PNP transistor disconnects the load from the input during shutdown. The PNP control circuitry is designed to keep the PNP out of saturation across a wide range of current, to keep quiescent current to a minimum and to provide current limiting to protect the chip during short-circuit conditions. Burst Mode is a registered a trademark of Linear Technolgy Corporation. 3464f 6 LT3464 U W W SWITCHI G TI E WAVEFOR S Operating Waveforms Start up Waveforms IL 0.1A/DIV IL 0.1A/DIV VOUT 50mV/DIV VOUT 10V/DIV VIN = 5V VOUT = 20V ILOAD = 1mA L = 22µH 50µs/DIV 5µs/DIV Shutdown Waveforms SHDN 5V/DIV VIN = 5V CAP PIN VOLTAGE VOUT: THE OUTPUT DISCONNECT ALLOWS VOUT TO BE AT GROUND DURING SHUTDOWN GND 1ms/DIV 3464f 7 LT3464 U U W U APPLICATIO S I FOR ATIO in discontinuous mode. If the left hand side of inequality 1 evaluates to less than Ot FF, then use Equation 3 to calculate maximum output current. Otherwise, use Equation 2. Choosing an Inductor The low current limit and fast switching of the LT3464 allow the use of very small surface mount inductors. The minimum inductor size that may be used in a given application depends on required efficiency and output current. Some inductors that work with the LT3464 are listed in Table 1, although there are many other manufacturers and devices that can be used. Consult each manufacturer for more detailed information and for their entire selection of related parts. Many different sizes and shapes are available. This inequality is true when the LT3464 is operating in discontinuous mode. LILIM < tOFF (VOUT – VIN + VF ) Use this equation to calculate the maximum output current when the LT3464 is operating in continuous mode. Table 1. Recommended Inductors IOUT (CM) = PART NUMBER µH DCR (Ω) CURRENT (mA) MANUFACTURER LQH32CN680K53 LQH32CN470K53 LQH32CN220K53 68 47 22 2.2 1.3 0.71 130 170 250 Murata 814-237-1431 www.murata.com ELJPC220KF ELJPA470KF 22 47 4.0 2.25 160 135 Panasonic 714-373-7334 www.panasonic.com CMD4D11-47 47 2.2 180 Sumida 847-956-0666 www.Sumida.com LB2016-220 LEM2520-220 LEM2520-330 LEMC2520-220 LEMC2520-330 LEMF2520-220 LEMC3225-680 LEMC3225-101 22 22 33 22 33 22 68 100 1.0 5.5 7.1 2.7 4.8 1.2 3.3 4.3 105 125 110 160 120 105 120 100 (INEQUALITY 1) (2LILIM + tOFF (VIN – VOUT – VF ))(VIN – VCESAT ) 2L(VOUT – VCESAT + VF ) (2) Use this equation to calculate the maximum output current when the LT3464 is operating in discontinuous mode. IOUT (DCM) = 2 LILIM (VIN – VCESAT ) (3) 2(LILIM + VIN tOFF – tOFF VCESAT )(– VIN + VOUT + VF ) Taiyo Yuden 408-573-4150 www.t-yuden.com Where VF is the Schottky forward voltage,LIM I is the switch current limit, tOFF is the switch off time, and VCESAT is the switch saturation voltage. See the Electrical Specifications. Figures 1 through 3 show the worst-case maximum output current as given by Equations 2 and 3 using 20% inductor The following set of formulas can be used to calculate derating and worst-case LT3464 specifications. Also note maximum output current given V IN, VOUT and L values. that for some applications the maximum output current is Inequality 1 is used to determine if the LT3464 is operating limited to 25mA by the output disconnect circuitry. 25 25 15.0 L = 47µH 20 L = 47µH IOUT (mA) IOUT (mA) L = 22µH 10.0 L = 10µH 7.5 5.0 15 L = 10µH 10 0 10 15 20 25 30 35 3464 F01 Figure 1. Maximum Output Current VIN = 3.6V 15 L = 22µH L = 10µH 10 5 L = 4.7µH L = 4.7µH L = 4.7µH VOUT (V) 8 L = 22µH 5 2.5 0 20 L = 47µH 12.5 IOUT (mA) 17.5 10 15 0 20 25 VOUT (V) 30 35 3464 F02 Figure 2. Maximum Output Current VIN = 5V 15 20 25 VOUT (V) 30 35 3464 F03 Figure 3. Maximum Output Current VIN = 8.4V 3464f LT3464 U W U U APPLICATIO S I FOR ATIO user to select between using the built-in reference, and supplying an external reference voltage. The voltage at the The small size and low ESR of ceramic capacitors makes CTRL pin can be adjusted while the chip is operating to them suitable for LT3464 applications. X5R and X7R types alter the output voltage of the LT3464 for purposes such are recommended because they retain their capacitance as display dimming or contrast adjustment. To use the over wider voltage and temperature ranges than other internal 1.25V reference, the CTRL pin must be held higher types such as Y5V or Z5U. A 1 µF input capacitor and a than 1.5V, which can be done by tying it to VIN. When the 0.22µF to 0.47µF output capacitor are sufficient for most CTRL pin is held between 0V and 1.2V the LT3464 will LT3464 applications. Always use a capacitor with a suffiregulate the output such that the FB pin voltage is equal to cient voltage rating. Table 2 shows a list of several capacithe CTRL pin voltage. tor manufacturers. Consult the manufacturers for more detailed information and for their entire selection of related To set the output voltage, select the values of R1 and R2 according to the following equation (see Figure 4). parts. Capacitor Selection Table 2. Recommended Ceramic Capacitor Manufacturers MANUFACTURER PHONE URL Taiyo Yuden 408-573-4150 www.t-yuden.com AVX 843-448-9411 www.avxcorp.com Murata 814-237-1431 www.murata.com Kemet 408-986-0424 www.kemet.com V R2 = R1 OUT – 1 VREF Where VREF =1.25V if the internal reference is used, or VREF = VCTRL if VCTRL is between 0V and 1.2V. Choosing a Feedback Node Output Voltage Ripple The top of the feedback divider may be connected to the OUT pin or to the CAP pin (see Figure 4). Regulating the OUT pin eliminates the output offset resulting from the voltage drop across the output disconnect. However, in the case of a short-circuit fault at the OUT pin, the LT3464 will switch continuously because the FB pin is low. While operating in this open-loop condition, the rising voltage at the CAP pin is limited only by the current limit of the output disconnect. Given worst-case parameters this voltage may reach 25V. When the short-circuit is removed, the The LT3464 also includes an on-chip phase-lead capacitor OUT pin will bounce up to the voltage on the CAP pin, potentially exceeding the set output voltage until the between the CAP pin and the FB pin to greatly reduce capacitor voltages fall back into regulation. While this is ripple; however, certain applications can benefit from harmless to the LT3464, this should be considered in the additional capacitance in parallel with the integrated capacitor, which may be added externally between the CAP context of the external circuitry if short-circuit events are and FB pins. Typical effective values range from 4.7pF to expected. 20pF. Since the FB pin sits at a low voltage, be sure the Regulating the CAP pin ensures that the voltage on the chosen capacitor has a sufficient voltage rating. OUT pin never exceeds the set output voltage after a shortcircuit event. However, this setup does not compensate Setting Output Voltage and the for the voltage drop across the output disconnect, resultAuxiliary Reference Input ing in an output voltage that is slightly lower than the voltage set by the resistor divider. The next section disThe LT3464 is equipped with both an internal 1.25V reference and an auxiliary reference input. This allows the cusses how to compensate for this drop. Using low ESR capacitors will help minimize the output ripple voltage, but proper selection of the inductor and the output capacitor also plays a big role. The LT3464 provides energy to the load in bursts by ramping up the inductor current, then delivering that current to the load. If too large an inductor value or too small a capacitor value is used, the output ripple voltage will increase because the capacitor will be slightly overcharged each burst cycle. To reduce this effect, a larger output capacitor may be used. 3464f 9 LT3464 U W U U APPLICATIO S I FOR ATIO 300 6 7 6 SW VIN SW OUT CTRL LT3464 CAP 8 SHDN FB GND 4 3 5 VOUT R2 1 OUT CTRL LT3464 CAP 8 2 3 VOUT 5 R2 SHDN FB R1 250 GND VCAP-OUT (SAT) 1 7 VIN 200 150 100 2 R1 4 50 0 3464 F01 0 5 10 15 20 25 COLLECTOR CURRENT (mA) 30 3464 F02 Figure 4. Feedback Connection Using the CAP Pin and the OUT Pin Output Disconnect Considerations The LT3464 is equipped with an output disconnect that isolates the load from the input during shutdown. See the Operation section for a functional diagram. The output disconnect uses a pass PNP coupled with circuitry that varies the base current such that the transistor is consistently at the edge of saturation, thus yielding the best compromise between VCE(SAT) and low quiescent current. To remain stable, this circuit requires a bypass capacitor connected between the OUT pin and the CAP pin or between the OUT pin and ground. A ceramic capacitor with a value of at least 0.1µF is a good choice. The PNP V CE(SAT) varies with load current as shown in Figure 5. This voltage drop (VDROP) can be accounted for when using the CAP pin as the feedback node by setting the output voltage according to the following formula: V + VDROP R2 = R1 OUT – 1 VREF Figure 5: Output Disconnect Voltage Drop (VDROP) vs Current indefinite short, but care must be taken to avoid exceeding the maximum junction temperature. Inrush Current When VIN is stepped from ground to operating voltage while the output capacitor is discharged, an inrush current will flow through the inductor and integrated Schottky diode into the output capacitor. Conditions that increase inrush current include a larger more abrupt voltage step at VIN, a larger output capacitor tied to the CAP pin, and an inductor with a low saturation current. While the internal diode is designed to handle such events, the inrush current should not be allowed to exceed 1 amp. For circuits that use output capacitor values within the recommended range and have input voltages of less than 5V, inrush current remains low, posing no hazard to the device. In cases where there are large steps at V IN (more than 5V) and/or a large capacitor is used at the CAP pin, inrush current should be measured to ensure safe operation. In addition, the disconnect circuit has a built in current limit of 25mA (minimum) to protect the chip during shortcircuit. This feature allows the LT3464 to tolerate an 3464f 10 LT3464 U W U U APPLICATIO S I FOR ATIO pin has sharp rising and falling edges. Minimize the length As with all switching regulators, careful attention must be and area of all traces connected to the SW pin and always paid to the PCB board layout and component placement. use a ground plane under the switching regulator to To maximize efficiency, switch rise and fall times are made minimize interplane coupling. In addition, the ground as short as possible. To prevent electromagnetic interfer- connection for the feedback resistor R1 should be tied ence (EMI) problems, proper layout of the high frequency directly to the GND pin and not shared with any other component, ensuring a clean, noise-free connection. Recswitching path is essential. The voltage signal of the SW ommended component placement is shown in Figure 6. Board Layout Considerations GND VIN GND VOUT VIAS TO GROUND PLANE VIA TO CONTROL VIA TO SHDN 3464 F07 Figure 6. Recommended Layout 3464f 11 LT3464 U TYPICAL APPLICATIO S 15V Output Converter with Output Disconnect L1 22µH VIN 2.3V TO 10V C1 1µF 1 7 6 VIN SW OUT CTRL LT3464 8 CAP SHDN FB 3 5 2 VOUT 15V C3 0.22µF C2 0.22µF VIN (V) IOUT (mA) 3.6 7.0 5.0 10.0 8.4 19.0 VIN (V) IOUT (mA) 3.6 3.5 5.0 4.5 8.4 7.5 R2 3.32M R1 301k GND 4 C1: TAIYO YUDEN LMK107 BJ105MA-T C2: TAIYO YUDEN EMK107 BJ224MA-T C3: TAIYO YUDEN EMK107 BJ224MA-T L1: MURATA LQH32CN220K 3464 TA02 34V Output Converter with Output Disconnect L1 47µH VIN 2.3V TO 10V C1 1µF 1 7 6 VIN SW OUT CTRL LT3464 8 CAP SHDN FB 3 5 2 VOUT 34V C3 0.22µF C2 0.33µF R2 2.61M R1 100k GND 4 C1: TAIYO YUDEN LMK107 BJ105MA-T C2: TAIYO YUDEN GMK212 BJ334MG-T C3: TAIYO YUDEN UMK212 BJ224MG-T L1: MURATA LQH32CN470K 3464 TA03 20V Output Converter with Output Disconnect Using an 0805 Inductor and 0603 Capacitors L1 10µH VIN 2.3V TO 10V C1 1µF 1 7 6 VIN SW OUT CTRL LT3464 8 CAP SHDN FB 3 5 2 VOUT 20V C3 0.1µF C2 0.1µF R2 4.53M R1 301k GND 4 C1: TAIYO YUDEN LMK107 BJ105MA-T C2: TAIYO YUDEN TMK107 BJ104MA-T C3: TAIYO YUDEN TMK107 BJ104MA-T L1: TAIYO YUDEN LB 2012T100MR VIN (V) IOUT (mA) 3.6 3.0 5.0 4.0 8.4 6.0 3464 TA04 3464f 12 LT3464 U TYPICAL APPLICATIO S 20V Output Converter with Output Disconnect L1 47µH VIN 2.3V TO 10V C1 1µF 1 7 6 VIN SW OUT CTRL LT3464 8 CAP SHDN FB 3 VOUT 20V C3 0.22µF 5 C2 0.33µF 2 R2 4.53M R1 301k GND 4 VIN (V) IOUT (mA) 3.6 6.0 5.0 9.0 8.4 16.5 VIN (V) IOUT (mA) 3.6 5.0 3464 TA05 C1: TAIYO YUDEN LMK107 BJ105MA-T C2: TAIYO YUDEN GMK212 BJ334MG-T C3: TAIYO YUDEN UMK212 BJ224MG L1: MURATA LQH32CN470K 20V Output Converter with Soft Start L1 22µH VIN 2.3V TO 10V OFF ON C4 1µF 8 R1 300k 7 6 VIN SW OUT SHDN LT3464 1 C4 0.1µF CAP CTRL FB 3 5 2 VOUT 20V C3 0.22µF C2 0.33µF R2 4.53M R1 301k GND 4 C1: TAIYO YUDEN LMK107 BJ105MA-T C2: TAIYO YUDEN GMK212 BJ334MG-T C3: TAIYO YUDEN EMK107 BJ224MA-T L1: MURATA LQH32CN220K 5.0 6.5 8.4 11.0 3464 TA06 3464f 13 LT3464 U TYPICAL APPLICATIO S 8V Output Converter with Output Disconnect L1 22µH VIN 2.3V TO 7V 6 7 VIN C4 1µF 8 SW SHDN LT3464 1 3 OUT 5 CAP CTRL C2 2.2µF 2 FB VOUT 8V C3 0.47µF R2 1.62M C4 20pF VIN (V) IOUT (mA) 3.6 13.5 5.0 20 R1 301k GND 4 3464 TA07 C1: TAIYO YUDEN CE LMK107 BJ105MA-T C2: TAIYO YUDEN CE LMK212 BJ225MG-T C3: TAIYO YUDEN CE LMK107 BJ474MA-T L1: MURATA LQH32CN220K ±20V Dual Output Converter with Output Disconnect L1 47µH VIN 2.3V TO 10V C1 1µF SW OUT CTRL LT3464 8 D2 6 7 VIN 1 C5 D1 0.33µF –VOUT I = 2.5mA AT VIN = 3.6V –20V OUT C4 0.33µF CAP SHDN FB 3 5 2 VOUT 20V C3 0.22µF C2 0.33µF IOUT = 2.5mA AT VIN = 3.6V R2 4.53M R1 301k GND 4 3464 TA08 C1: TAIYO YUDEN LMK107 BJ105MA-T C2, C4, C5: TAIYO YUDEN GMK212 BJ334MG-T C3: TAIYO YUDEN UMK212 BJ224MG-T L1: MURATA LQH32CN470K D1, D2: CENTRAL CMDSH-3 3464f 14 LT3464 U PACKAGE DESCRIPTIO TS8 Package 8-Lead Plastic TSOT-23 (Reference LTC DWG # 05-08-1637) 0.52 MAX 2.90 BSC (NOTE 4) 0.65 REF 1.22 REF 1.4 MIN 3.85 MAX 2.62 REF 2.80 BSC 1.50 – 1.75 (NOTE 4) PIN ONE ID RECOMMENDED SOLDER PAD LAYOUT PER IPC CALCULATOR 0.22 – 0.36 8 PLCS (NOTE 3) 0.65 BSC 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 (NOTE 3) 1.95 BSC 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 TS8 TSOT-23 0802 3464f 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 LT3464 U TYPICAL APPLICATIO S 20V Output Converter with Variable Output Voltage and Shutdown VIN 2.3V TO 10V L1 22µH C1 1µF 1 DAC 7 6 VIN SW OUT CTRL LT3464 8 µC CAP SHDN FB 3 5 2 VOUT 20V C3 0.22µF C2 0.33µF R2 4.53M R1 301k GND 4 VIN (V) IOUT (mA) 3.6 5.0 5.0 6.5 8.4 11.0 3464 TA09 C1: TAIYO YUDEN LMK107 BJ105MA-T C2: TAIYO YUDEN GMK212 BJ334MG-T C3: TAIYO YUDEN GMK212 BJ224MG-T L1: MURATA LQH32CN220K RELATED PARTS PART NUMBER DESCRIPTION COMMENTS LT1613 550mA (ISW), 1.4MHz, High Efficiency Step-Up DC/DC Converter VIN = 0.9V to 10V, VOUT(MAX) = 34V, IQ = 3mA, ISD = <1µA, ThinSOT Package LT1615/ LT1615-1 300mA/80mA (ISW), Constant Off-Time, High Efficiency Step-Up DC/DC Converter VIN = 1.2V to 15V, VOUT(MAX) = 34V, IQ = 20µA, ISD = <1µA, ThinSOT Package LT1618 Constant Current, Constant Voltage, 1.4MHz, High Efficiency Boost Regulator VIN = 1.6V to 18V, VOUT(MAX) = 34V, IQ = 1.8mA, ISD = <1µA, MS Package, Up to 6 White LEDs LT1932 Constant Current, 1.2MHz, High Efficiency White LED Boost Regulator VIN = 1V to 10V, VOUT(MAX) = 34V, IQ = 1.2mA, ISD = <1µA, ThinSOT Package, Up to 8 White LEDs LT1937 Constant Current, 1.2MHz, High Efficiency White LED Boost Regulator VIN = 2.5V to 10V, VOUT(MAX) = 34V, IQ = 1.9mA, ISD = <1µA, SC-70, ThinSOT Packages, Up to 4 White LEDs LT1944 Dual Output 350mA (ISW), Constant Off-Time, High Efficiency Step-Up DC/DC Converter VIN = 1.2V to 15V, VOUT(MAX) = 34V, IQ = 20µA, ISD = <1µA, MS Package LT1944-1 Dual Output 150mA (ISW), Constant Off-Time, High Efficiency Step-Up DC/DC Converter VIN = 1.2V to 15V, VOUT(MAX) = 34V, IQ = 20µA, ISD = <1µA, MS Package LT1945 Dual Output, ±350mA (ISW), Constant Off-Time, High Efficiency Step-Up DC/DC Converter VIN = 1.2V to 15V, VOUT(MAX) = ±34V, IQ = 20µA, ISD = <1µA, MS Package LTC3200/ LTC3200-5 Low Noise, 2MHz, Regulated Charge Pump White LED Driver VIN = 2.7V to 4.5V, IQ = 8mA, ISD = <1µA, MS, ThinSOT Packages, Up to 6 White LEDs LTC3201 Low Noise, 1.7MHz, Regulated Charge Pump White LED Driver VIN = 2.7V to 4.5V, IQ = 6.5mA, ISD = <1µA, MS Package, Up to 6 White LEDs LTC3202 Low Noise, 1.5MHz, Regulated Charge Pump White LED Driver VIN = 2.7V to 4.5V, IQ = 5mA, ISD = <1µA, MS Package, Up to 8 White LEDs LTC3400/ LTC3400B 600mA (ISW), 1.2MHz, Synchronous Step-Up DC/DC Converter VIN = 0.85V to 5V, VOUT(MAX) = 5V, IQ = 19µA/300µA, ISD = <1µA, ThinSOT Package LTC3401 1A (ISW), 3MHz, Synchronous Step-Up DC/DC Converter VIN = 0.5V to 5V, VOUT(MAX) = 6V, IQ = 38µA, ISD = <1µA, MS Package LTC3402 2A (ISW), 3MHz, Synchronous Step-Up DC/DC Converter VIN = 0.5V to 5V, VOUT(MAX) = 6V, IQ = 38µA, ISD = <1µA, MS Package 3464f 16 Linear Technology Corporation LT/TP 0204 1K • PRINTED IN USA 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 ● FAX: (408) 434-0507 ● www.linear.com LINEAR TECHNOLOGY CORPORATION 2003