LT3507A - Triple Monolithic Step-Down Regulator with LDO

Features

  • Wide Input Range: 4V to 36V
  • One 2.7A and Two 1.8A Output Switching Regulators with Internal Power Switches
  • Low Dropout Linear Regulator with External Transistor
  • Antiphase Switching Reduces Ripple
  • Independent Run, Tracking/Soft-Start, and Power Good Indicators Ease Supply Sequencing
  • Uses Small Inductors and Ceramic Capacitors
  • Adjustable, 250kHz to 2.5MHz Switching Frequency, Synchronizable Over the Full Range
  • User Programmable Overvoltage and Undervoltage Lockouts
  • Thermally Enhanced, 38-Lead TSSOP and 5mm × 7mm QFN Packages
Designed for Automotive and Transportation Applications
AEC-Q100 data available for specific packages


Typical Application

LT3507A Typical Application
LT3507A Typical Application

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.

  Output Current Package
LT3507 2.5A, 1.5A, 1.5A 5x7 QFN-38
LT3507A 2.7A, 1.8A, 1.8A 5x7 QFN-38, TSSOP-38E

Packaging

CAD Symbols and Footprints: The downloadable Zip file below contains the schematic symbol and PCB footprints.

For complete and up to date package information and drawings, please refer to our packaging page

Part Number Package Code Temp Package
Drawing
RoHS
LT3507AEFE#PBF TSSOP-38 FE E 05-08-1772 Yes
LT3507AEFE#TRPBF TSSOP-38 FE E 05-08-1772 Yes
LT3507AEUHF#PBF 5x7 QFN-38 UHF E 05-08-1701 Yes
LT3507AEUHF#TRPBF 5x7 QFN-38 UHF E 05-08-1701 Yes
LT3507AHFE#PBF TSSOP-38 FE H 05-08-1772 Yes
LT3507AHFE#TRPBF TSSOP-38 FE H 05-08-1772 Yes
LT3507AHUHF#PBF 5x7 QFN-38 UHF H 05-08-1701 Yes
LT3507AHUHF#TRPBF 5x7 QFN-38 UHF H 05-08-1701 Yes
LT3507AIFE#PBF TSSOP-38 FE I 05-08-1772 Yes
LT3507AIFE#TRPBF TSSOP-38 FE I 05-08-1772 Yes
LT3507AIUHF#PBF 5x7 QFN-38 UHF I 05-08-1701 Yes
LT3507AIUHF#TRPBF 5x7 QFN-38 UHF I 05-08-1701 Yes


LT3507A Package Drawing
LT3507A Package Drawing

Order Info

  • Part numbers ending in PBF are lead free. Solder plated terminal finish (SnPb) versions are non-standard and special terms and conditions and pricing applies if available. Please contact LTC marketing for information.
  • Part numbers containing TR or TRM are shipped in tape and reel or 500 unit mini tape and reel, respectively
  • Please refer to our general ordering information or the product datasheet for more details

Package Variations and Pricing

Part Number Package Temp Price
(1-99)
Price
(1k)*
RoHS
LT3507AEFE#PBF TSSOP-38 E $6.50 $4.55 Yes
LT3507AEFE#TRPBF TSSOP-38 E $4.61 Yes
LT3507AEUHF#PBF 5x7 QFN-38 E $6.07 $4.25 Yes
LT3507AEUHF#TRPBF 5x7 QFN-38 E $4.31 Yes
LT3507AHFE#PBF TSSOP-38 H $8.07 $5.65 Yes
LT3507AHFE#TRPBF TSSOP-38 H $5.71 Yes
LT3507AHUHF#PBF 5x7 QFN-38 H $7.64 $5.35 Yes
LT3507AHUHF#TRPBF 5x7 QFN-38 H $5.41 Yes
LT3507AIFE#PBF TSSOP-38 I $7.71 $5.40 Yes
LT3507AIFE#TRPBF TSSOP-38 I $5.46 Yes
LT3507AIUHF#PBF 5x7 QFN-38 I $7.29 $5.10 Yes
LT3507AIUHF#TRPBF 5x7 QFN-38 I $5.16 Yes
Buy NowRequest Samples
* The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Linear Technology sales office or authorized distributor.

Demo Boards

Linear Technology offers many demo boards free of charge to qualified customers. Contact your local sales office or distributor to inquire about a demo board. Certain demo boards are also available for sale via credit card on this website. Demo boards are for evaluation purposes only. It remains the customer’s responsibility to verify proper and reliable operation in the actual end application.

Part Number Description Price Documentation
DC1781A LT3507AEFE Demo Board | 7V to 36VIN, VOUT1 =1.8V @ 2.7A, VOUT2 =3.3V @1.5A, VOUT3 = 5.0V @1.8A, VOUT4 =2.5V @ 0.3A $175.00
Buy Now
Click here to view our complete list of demo boards

Designed for Automotive and Transportation Applications

AEC-Q100 data is available for these specific part numbers. Please contact your local sales representative for more information regarding reliability reports or to inquire about parts that are not included. For more information, view our Automotive and Transportation page

Part Number Package Temp Price
(1-99)
Price
(1k)*
RoHS
LT3507AHFE#PBF TSSOP-38 H $8.07 $5.65 Yes
LT3507AHFE#TRPBF TSSOP-38 H $5.71 Yes
LT3507AHUHF#PBF 5x7 QFN-38 H $7.64 $5.35 Yes
LT3507AHUHF#TRPBF 5x7 QFN-38 H $5.41 Yes
LT3507AIFE#PBF TSSOP-38 I $7.71 $5.40 Yes
LT3507AIFE#TRPBF TSSOP-38 I $5.46 Yes
LT3507AIUHF#PBF 5x7 QFN-38 I $7.29 $5.10 Yes
LT3507AIUHF#TRPBF 5x7 QFN-38 I $5.16 Yes
Buy NowRequest Samples
* The USA list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Linear Technology sales office or authorized distributor.

Applications

  • Automotive
  • Industrial Supplies
  • Distributed Power Regulation
  • DSP Power

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Design Tools

LTspice

LTspice® software is a powerful, fast and free simulation tool, schematic capture and waveform viewer with enhancements and models for improving the simulation of switching regulators. Click here to download LTspice

To launch a ready to run LTspice demonstration circuit for this part:

To explore other ready to run LTspice demonstration circuits, please visit our Demo Circuits Collection.

Models for the following parts are available in LTspice:
LT3507
LT3507A

LTpowerCAD

The LTpowerCAD design tool is a complete power supply design tool program that can significantly ease the tasks of power supply design. It guides users to a solution, selects power stage components, provides detailed power efficiency, shows quick loop bode plot stability and load transient analysis, and can export a final design to LTspice for simulation. Click here to download LTpowerCAD

Design tools for the following parts are available in LTpowerCAD:
LT3507
LT3507A

Technical Support