Features and Benefits
- 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
The LT3507A 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.
|LT3507||2.5A, 1.5A, 1.5A||5x7 QFN-38|
|LT3507A||2.7A, 1.8A, 1.8A||5x7 QFN-38, TSSOP-38E|
- Industrial Supplies
- Distributed Power Regulation
- DSP Power
Product Lifecycle Production
At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.
Evaluation Kits (1)
Demo circuit 1781A is a Triple Monolithic Step-Down Regulator with LDO featuring the LT3507A. The demo circuit is designed for 1.8V, 3.3V, 5.0V and 2.5V outputs from a 7V to 36V input. The current capability of each channel is 2.7A, 1.5A, 1.8A and 0.3A respectively. Independent input voltage, feedback, soft-start and power good pins for each channel simplify complex power supply tracking/sequencing requirements.
All three converters are either synchronized to a common external clock input or single-resistor programmable from 250kHz to 2.5MHz using internal oscillator. At all frequencies, a 180° phase shift between VOUT1 and the other two outputs is maintained, reducing input voltage ripple and component size. Programmable frequency allows for optimization between efficiency and external component size.
Tools & Simulations
LTspice® is a powerful, fast and free simulation software, schematic capture and waveform viewer with enhancements and models for improving the simulation of analog circuits.
To launch ready-to-run LTspice demonstration circuits for this part:
Step 1: Download and install LTspice on your computer.
Step 2: Click on the link in the section below to download a demonstration circuit.
Step 3: If LTspice does not automatically open after clicking the link below, you can instead run the simulation by right clicking on the link and selecting “Save Target As.” After saving the file to your computer, start LTspice and open the demonstration circuit by selecting ‘Open’ from the ‘File’ menu.
Models for the following parts are available in LTspice:
LTpowerCAD® is a power supply design program which selects power stage components, provides detailed power efficiency, shows quick loop Bode plot stability and load transient analysis, and can export to LTspice for simulation.
Design tools for the following parts are available in LTpowerCAD:
ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well. "Zero defects" for shipped products is always our goal.
Sample & Buy
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 Analog Devices, Inc. sales office or authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.