LT3509 LINER [Linear Technology], LT3509 Datasheet
LT3509
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LT3509 Summary of contents
Page 1
... The high maximum switching frequency allows the use of small inductors and ceramic capacitors for low ripple. Constant frequency operation above the AM band avoids interference with radio reception, making the LT3509 well suited for automotive applications. Each regulator has an independent shutdown and soft-start control pin. ...
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... For more information on tape and reel specifi cations, go to: 2 Operating Junction Temperature Range (Notes 3, 5) LT3509E ............................................. –40°C to 125°C LT3509I .............................................. –40°C to 125°C Storage Temperature Range ................... –65°C to 150°C Lead Temperature (Soldering, 10 sec.) MSE16 Package ................................................ 300°C ...
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... Note 2. Absolute Maximum Voltage at the second transients and 36V for continuous operation. Note 3. The LT3509E is guaranteed to meet performance specifi cations from 0°C to 125°C junction temperature. Specifi cations over the –40°C to 125°C operating junction temperature range are assured by design, characterization ...
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... LT3509 TYPICAL PERFORMANCE CHARACTERISTICS Effi ciency vs Load Current 2.0MHz OUT 25º 12V 24V 0.4 0.6 0.2 (A) I LOAD 3509 G01 Switch CE(SAT 25ºC A 0.3 0.25 0.2 0.15 0.1 0. 0.4 0.6 0.2 ( Boost Diode Characteristics 1 25º 0.8 0.6 0.4 0 ...
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... T = 25º 85ºC 100 0.6 0.8 −50 3509 G11 1.8 1.6 1.4 1.2 1 0.8 0.6 0.4 0 120 3509 G13 LT3509 Max V for Constant Frequency 3.3V 2MHz OUT 100 125 0 0.2 0.4 I (A) LOAD 3509 G09 Min ON Time vs. Temperature I = 0.3A LOAD − ...
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... LT3509 PIN FUNCTIONS (DFN/MSE) DA1, DA2 (Pins Pins 1, 8): The DA pins are the anode connections for the catch diodes. These are con- nected internally to the exposed ground pad by current sensing resistors. BOOST1, BOOST2 (Pins Pins 2, 7): The BOOST pins are used to dynamically boost the power transistor ...
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... DIODE MAIN CURRENT COMPARATOR SWITCH SWITCH LOGIC DRIVER DA CURRENT COMPARATOR –17mV V C – ERROR SLOPE AMPLIFIER V REF 0.8V CLAMP Figure 1. Functional Block Diagram LT3509 BD NOTE: THE BD PIN IS COMMON TO BOTH CHANNELS. BOOST POWER SWITCH OUT 18m FB R2 3509 BD GND ...
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... LT3509 OPERATION Overview The LT3509 is a dual, constant frequency, current mode switching regulator with internal power switches. The two independent channels share a common voltage reference and oscillator and operate in phase. The switching frequency is set by a single resistor and can also be synchronized to an external clock ...
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... SW Where MHz and R SW Table 1. Standard E96 Resistors for Common Frequencies FREQUENCY 270 kHz 300 kHz 400kHz 500kHz 1MHz 2MHz 2.2MHz 3509 F02 LT3509 ⎞ V OUT – 1 ⎠ ⎟ for any desired frequency in the T ⎞ – 166 • ...
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... LDO. Input Voltage Range Firstly, the LT3509 imposes some hard limits due to the undervoltage lock-out and the overvoltage protection. A given application will also have a reduced, normal operating . For example, T range over which maximum effi ...
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... MIN Above this voltage the only way the LT3509 can maintain regulation is to skip cycles so the effective freqeuncy will reduce. This will cause an increase in ripple and the switch- ing noise will shift to a lower frequency. This calculation will in practice drive the maximum switching frequency for a desired step-down ratio ...
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... LT3509 APPLICATIONS INFORMATION Minimum Input Voltage and Boost Architecture The minimum operating voltage is determined either by the LT3509’s internal undervoltage lockout of ~3. its maximum duty cycle. The maximum duty cycle for fi xed frequency operation is given by: = − • f MAX OFF MIN ...
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... The LT3509 limits its switch current in order to protect itself and the system from over-current 3509 F07 faults. Therefore, the maximum output current that the LT3509 will deliver depends on the switch current limit, the inductor value and the input and output voltages ...
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... I SWPK LPK OUT 2 To maintain output regulation, this peak current must be less than the LT3509’s switch current limit I dependent on duty cycle due to the slope compensation. For least 1.4A at low duty cycles and decreases LIM linearly to 1. 0.8. The theoretical minimum inductance can now be calcu- ...
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... PCB footprint. 0.065 3.0 Figure 10 shows an equivalent circuit for the LT3509 control loop. The error amp is a transconductance amplifi er with 0.06 1.8 fi nite output impedance. The power section, consisting of 0.07 1 ...
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... C OUT The low ESR and small size of ceramic capacitors make them the preferred type for LT3509 applications. Not all ceramic capacitors are the same, however. Many of the higher value capacitors use poor dielectrics with high temperature and voltage coeffi cients. In particular, Y5V and Z5U types lose a large fraction of their capacitance with applied voltage and at temperature extremes ...
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... I LOAD 700mA 300mA V (AC) OUT 50mV/DIV = 10μ and C Load Current Step from 300mA to 700mA PL = 12V 3.3V OUT LT3509 TIME 20μs/DIV C = 10μ 82pF OUT PL 3509 F11 = 2.0MHz SW 3509f 17 ...
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... LT3509 has no input. This may occur in battery charging applications or in battery backup systems where a bat- tery or some other supply is diode OR-ed with one of the LT3509 regulated outputs. If the SW pin is at more than about 4V the V control circuitry to power-up to the quiescent bias level and up to 2mA could be drawn from the backup supply. ...
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... The low-loss ceramic capacitor combined with the just a small amount of wiring inductance forms an underdamped resonant tank circuit and the voltage at the V pin of the LT3509 can ring to twice the nominal IN input voltage. See Linear Technology Application Note 88 for more details. PCB Layout and Thermal Design The PCB layout is critical to both the electrical and thermal performance of the LT3509 ...
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... Outputs, Synchronized to 300kHz to 600kHz V = 4.5V TO 36V IN TRANSIENT TO 60V V = 1.8V OUT 0.7A CLOCK 1.6V 0.4V 20 2.2μ BOOST1 BOOST2 0.22μF 10μH SW1 SW2 LT3509 UPS140 DA1 DA2 12.4k FB1 FB2 RUN/SS1 RUN/SS2 10k SYNC R GND T 22μF 22nF 178k NOTE: R CHOSEN FOR 264kHz T 0.22μF 15μH UPS140 31 ...
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... Logic Supply and 8V for LCD Display with Display Power Controlled by Logic 2.2μ BOOST1 BOOST2 0.22μF 6.8μH SW1 SW2 LT3509 DFLS140L DA1 DA2 52.3k FB1 FB2 RUN/SS1 RUN/SS2 10k SYNC R GND 10k T 22nF 0.1μF 40. 1MHz SW LT3509 0.22μF 10μH DFLS140L 90.9k 10k 10μF 3509 TA04 21 3509f ...
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... LT3509 PACKAGE DESCRIPTION 3.30 0.05 3.60 0.05 2.20 0.05 1.70 0.05 RECOMMENDED SOLDER PAD PITCH AND DIMENSIONS APPLY SOLDER MASK TO AREAS THAT ARE NOT SOLDERED 4.00 0.10 (2 SIDES) PIN 1 TOP MARK (SEE NOTE 6) 0.200 REF NOTE: 1. DRAWING PROPOSED TO BE MADE VARIATION OF VERSION (WGED-3) IN JEDEC PACKAGE OUTLINE MO-229 2. DRAWING NOT TO SCALE 3. ALL DIMENSIONS ARE IN MILLIMETERS 4 ...
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... DETAIL “A” 1.10 (.043) MAX SEATING PLANE 0.17 – 0.27 (.007 – .011) 0.50 TYP (.0197) BSC LT3509 8 0.35 REF 1.651 0.102 0.12 REF (.065 .004) DETAIL “B” CORNER TAIL IS PART OF DETAIL “B” THE LEADFRAME FEATURE. FOR REFERENCE ONLY 9 NO MEASUREMENT PURPOS 0 ...
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... Linear Technology Corporation 24 1630 McCarthy Blvd., Milpitas, CA 95035-7417 (408) 432-1900 FAX: (408) 434-0507 ● 2MHz, 5V and 3.3V Outputs 2.2μ BOOST1 BOOST2 0.1μF 0.1μF 6.8μH 4.7μH SW1 SW2 LT3509 MBRM140 MBRM140 DA1 DA2 52.3k FB1 FB2 RUN/SS1 RUN/SS2 10k SYNC R GND 22nF T 22nF 16.9k 10k ...