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LT3507A Dataheets PDF



Part Number LT3507A
Manufacturers Linear
Logo Linear
Description Triple Monolithic Step-Down Regulator
Datasheet LT3507A DatasheetLT3507A Datasheet (PDF)

FEATURES n Wide Input Range: 4V to 36V n One 2.7A and Two 1.8A Output Switching Regulators with Internal Power Switches n Low Dropout Linear Regulator with External Transistor n Antiphase Switching Reduces Ripple n Independent Run, Tracking/Soft-Start, and Power Good Indicators Ease Supply Sequencing n Uses Small Inductors and Ceramic Capacitors n Adjustable, 250kHz to 2.5MHz Switching Frequency, Synchronizable Over the Full Range n User Programmable Overvoltage and Undervoltage Lockouts.

  LT3507A   LT3507A


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FEATURES n Wide Input Range: 4V to 36V n One 2.7A and Two 1.8A Output Switching Regulators with Internal Power Switches n Low Dropout Linear Regulator with External Transistor n Antiphase Switching Reduces Ripple n Independent Run, Tracking/Soft-Start, and Power Good Indicators Ease Supply Sequencing n Uses Small Inductors and Ceramic Capacitors n Adjustable, 250kHz to 2.5MHz Switching Frequency, Synchronizable Over the Full Range n User Programmable Overvoltage and Undervoltage Lockouts n Thermally Enhanced, 38-Lead TSSOP and 5mm × 7mm QFN Packages APPLICATIONS n Automotive n Industrial Supplies n Distributed Power Regulation n DSP Power LT3507A Triple Monolithic Step-Down Regulator with LDO DESCRIPTION The LT®3507A is a triple, current mode, DC/DC converter with internal power switches and a low dropout regulator. The switching converters are step-down converters capable of generating one 2.7A output and two 1.8A outputs. All three converters are synchronized to a single oscillator. The 2.7A output runs with opposite phase to the other two converters, reducing input ripple current. Each regulator has independent shutdown and soft-start circuits, and generates a power good signal when its output is in regulation, easing power supply sequencing and interfacing with microcontrollers and DSPs. The switching frequency is set with a single resistor yielding a range of 250kHz to 2.5MHz. The high switching frequency allows the use of small inductors and capacitors resulting in a very small triple output supply. The constant switching frequency, combined with low impedance ceramic capacitors, results in low, predictable output ripple. Frequency foldback and thermal shutdown provide protection against fault conditions. The LT3507A provides higher output current than available with the LT3507. L, LT, LTC, LTM, Linear Technology and the Linear logo are registered trademarks of Linear Technology Corporation. All other trademarks are the property of their respective owners. TYPICAL APPLICATION 5V, 3.3V, 2.5V and 1.8V Step-Down Regulator VIN 6V TO 36V VOUT1 1.8V 2.7A VOUT3 5V 1.8A 22µF 4.7µH VIN1 VIN2 VIN3 BOOST1 BOOST2 0.22µF SW1 18.7k 100µF 15k 25.5k VOUT2 15µH 680pF FB1 VC1 LT3507A 0.22µF BOOST3 SW3 53.6k 22µF 10.2k 25.5k 680pF FB3 VC3 SW2 FB2 VC2 BIAS DRIVE RT/SYNC 107k GND FB4 0.22µF 10µH 34.8k 680pF 25.5k 11k 24.3k 11.5k VOUT2 3.3V 33µF 1.5A 2.2µF VOUT4 2.5V 0.3A fSW = 450kHz 3507A TA01a Start-Up Waveforms—Coincident Tracking 1V/DIV VOUT3 VOUT2 VOUT4 VOUT1 1ms/DIV 3507 TA01b 3507af 1 LT3507A ABSOLUTE MAXIMUM RATINGS (Note 1) VIN Pins....................................................... –0.3V to 36V BOOST Pins...............................................................55V BOOST Above SW......................................................25V PGOOD Pins...............................................................36V BIAS Pin.....................................................................16V TRK/SS, VC, FB, RT/SYNC Pins....................................6V RUN, OVLO, UVLO Pins............................................ VIN1 DRIVE Pin....................................................................5V Operating Junction Temperature Range (Notes 2, 5) LT3507AE, LT3507AI.......................... –40°C to 125°C LT3507AH........................................... –40°C to 150°C Storage Temperature Range................... –65°C to 150°C Lead Temperature (Soldering, 10 sec) TSSOP Only....................................................... 300°C PIN CONFIGURATION TOP VIEW SW1 SW1 VIN3 VIN3 SW3 SW3 BOOST3 BOOST1 1 VIN1 VIN1 VINSW OVLO 2 3 4 5 UVLO 6 VC1 7 TRK/SS1 8 FB1 9 PGOOD1 10 PGOOD2 11 PGOOD3 12 38 37 36 35 34 33 32 39 GND 13 14 15 16 17 18 19 31 VIN2 30 VIN2 29 SW2 28 SW2 27 BOOST2 26 TRK/SS4 25 FB4 24 DRIVE 23 VC2 22 FB2 21 TRK/SS2 20 FB3 RT/SYNC RUN1 RUN2 RUN3 BIAS TRK/SS3 VC3 UHF PACKAGE 38-LEAD (5mm × 7mm) PLASTIC QFN θJA = 34°C/W EXPOSED PAD (PIN 39) IS GND, MUST BE SOLDERED TO PCB VIN3 1 SW1 2 SW1 3 BOOST1 4 VIN1 VIN1 VINSW OVLO 5 6 7 8 UVLO 9 VC1 10 TRK/SS1 11 FB1 12 PGOOD1 13 PGOOD2 14 PGOOD3 15 RT/SYNC 16 RUN1 17 RUN2 18 RUN3 19 TOP VIEW 39 GND 38 SW3 37 BOOST3 36 VIN2 35 VIN2 34 NC 33 SW2 32 BOOST2 31 TRK/SS4 30 FB4 29 DRIVE 28 VC2 27 NC 26 FB2 25 TRK/SS2 24 FB3 23 VC3 22 TRK/SS3 21 BIAS 20 GND FE PACKAGE 38-LEAD PLASTIC TSSOP θJA = 24°C/W EXPOSED PAD (PIN 39) IS GND, MUST BE SOLDERED TO PCB ORDER INFORMATION LEAD FREE FINISH TAPE AND REEL PART MARKING* PACKAGE DESCRIPTION TEMPERATURE RANGE LT3507AEUHF#PBF LT3507AIUHF#PBF LT3507AHUHF#PBF LT3507AEFE#PBF LT3507AEUHF#TRPBF LT3507AIUHF#TRPBF LT3507AHUHF#TRPBF LT3507AEFE#TRPBF 3507A 3507A 3507A LT3507AFE 38-Lead (5mm × 7mm) Plastic QFN 38-Lead (5mm × 7mm) Plastic QFN 38-Lead (5mm × 7mm) Plastic QFN 38-Lead Plastic TSSOP –40°C to 125°C –40°C to 125°C –40°C to 150°C –40°C to 125°C LT3507AIFE#PBF LT3507AIFE#TRPBF LT3507AFE 38-Lead Plastic TSSO.


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