LT3508 - Dual Monolithic 1.4A Step-Down Switching Regulator
Features
- Wide Input Voltage Range: 3.7V to 36V
- Two 1.4A Output Switching Regulators with Internal Power Switches
- Adjustable 250kHz to 2.5MHz Switching Frequency
- Synchronizable over the Full Frequency Range
- Anti-Phase Switching Reduces Ripple
- Uses Small Inductors and Ceramic Capacitors
- Accurate Programmable Undervoltage Lockout
- Independent Tracking, Soft-Start and Power Good Circuits Ease Supply Sequencing
- Output Adjustable Down to 800mV
- Small 4mm × 4mm 24-Pin QFN or 16-Pin Thermally Enhanced TSSOP Surface Mount Packages
AEC-Q100 data available for specific packages
Typical Application
Description
The LT3508 is a dual current mode PWM step-down DC/DC converter with internal power switches capable of generating two 1.4A outputs. The wide input voltage range of 3.7V to 36V makes the LT3508 suitable for regulating power from a wide variety of sources, including automotive batteries, 24V industrial supplies and unregulated wall adapters. Both converters are synchronized to a single oscillator programmable up to 2.5MHz and run with opposite phases, reducing input ripple current. Its high operating frequency allows the use of small, low cost inductors and ceramic capacitors, resulting in low, predictable output ripple. Each regulator has independent tracking and softstart circuits and generates a power good signal when its output is in regulation, easing power supply sequencing and interfacing with microcontrollers and DSPs.
Cycle-by-cycle current limit, frequency foldback and thermal shutdown provide protection against shorted outputs, and soft-start eliminates input current surge during startup. The low current (<2µA) shutdown mode enables easy power management in battery-powered systems.
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 |
|---|---|---|---|---|---|
| LT3508EFE#PBF | TSSOP-16 | FE | E | 05-08-1663 (BA) | Yes |
| LT3508EFE#TRPBF | TSSOP-16 | FE | E | 05-08-1663 (BA) | Yes |
| LT3508EUF#PBF | 4x4 QFN-24 | UF | E | 05-08-1697 | Yes |
| LT3508EUF#TRPBF | 4x4 QFN-24 | UF | E | 05-08-1697 | Yes |
| LT3508HFE#PBF | TSSOP-16 | FE | H | 05-08-1663 (BA) | Yes |
| LT3508HFE#TRPBF | TSSOP-16 | FE | H | 05-08-1663 (BA) | Yes |
| LT3508HUF#PBF | 4x4 QFN-24 | UF | H | 05-08-1697 | Yes |
| LT3508HUF#TRPBF | 4x4 QFN-24 | UF | H | 05-08-1697 | Yes |
| LT3508IFE#PBF | TSSOP-16 | FE | I | 05-08-1663 (BA) | Yes |
| LT3508IFE#TRPBF | TSSOP-16 | FE | I | 05-08-1663 (BA) | Yes |
| LT3508IUF#PBF | 4x4 QFN-24 | UF | I | 05-08-1697 | Yes |
| LT3508IUF#TRPBF | 4x4 QFN-24 | UF | I | 05-08-1697 | Yes |
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 | |
|---|---|---|---|---|---|---|
| LT3508EFE#PBF | TSSOP-16 | E | $5.00 | $3.50 | Yes | |
| LT3508EFE#TRPBF | TSSOP-16 | E | $3.56 | Yes | ||
| LT3508EUF#PBF | 4x4 QFN-24 | E | $4.79 | $3.35 | Yes | |
| LT3508EUF#TRPBF | 4x4 QFN-24 | E | $3.41 | Yes | ||
| LT3508HFE#PBF | TSSOP-16 | H | $6.36 | $4.45 | Yes | |
| LT3508HFE#TRPBF | TSSOP-16 | H | $4.51 | Yes | ||
| LT3508HUF#PBF | 4x4 QFN-24 | H | $6.10 | $4.27 | Yes | |
| LT3508HUF#TRPBF | 4x4 QFN-24 | H | $4.33 | Yes | ||
| LT3508IFE#PBF | TSSOP-16 | I | $6.00 | $4.20 | Yes | |
| LT3508IFE#TRPBF | TSSOP-16 | I | $4.26 | Yes | ||
| LT3508IUF#PBF | 4x4 QFN-24 | I | $5.74 | $4.02 | Yes | |
| LT3508IUF#TRPBF | 4x4 QFN-24 | I | $4.08 | Yes | ||
| Buy Now • Request Samples | ||||||
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 |
|---|---|---|---|
| DC1060A | LT3508EFE/LT3508EUF Demo Board | $125.00 | |
| Buy Now | |||
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 | |
|---|---|---|---|---|---|---|
| LT3508HFE#PBF | TSSOP-16 | H | $6.36 | $4.45 | Yes | |
| LT3508HFE#TRPBF | TSSOP-16 | H | $4.51 | Yes | ||
| LT3508HUF#PBF | 4x4 QFN-24 | H | $6.10 | $4.27 | Yes | |
| LT3508HUF#TRPBF | 4x4 QFN-24 | H | $4.33 | Yes | ||
| LT3508IFE#PBF | TSSOP-16 | I | $6.00 | $4.20 | Yes | |
| LT3508IFE#TRPBF | TSSOP-16 | I | $4.26 | Yes | ||
| LT3508IUF#PBF | 4x4 QFN-24 | I | $5.74 | $4.02 | Yes | |
| LT3508IUF#TRPBF | 4x4 QFN-24 | I | $4.08 | Yes | ||
| Buy Now • Request Samples | ||||||
Applications
- Automotive
- DSP Power Supplies
- Wall Transformer Regulation
- DSL and Cable Modems
- PCI Express
People Who Viewed This Product Also Viewed
- LT3988 - Dual 60V Monolithic 1A Step-Down Switching Regulator
- LT1763 - 500mA, Low Noise, LDO Micropower Regulators
- LT8610 - 42V, 2.5A Synchronous Step-Down Regulator with 2.5μA Quiescent Current
- LT4363 - High Voltage Surge Stopper with Current Limit
- LT8471 - Dual Multitopology DC/DC Converters with 2A Switches and Synchronization
- LT3641 - Dual Monolithic Buck Regulator with Power-On Reset and Watchdog Timer
- LT3080 - Adjustable 1.1A Single Resistor Low Dropout Regulator
- LTC4364 - Surge Stopper with Ideal Diode
- LT3509 - Dual 36V, 700mA Step-Down Regulator
- LTC3115-1 - 40V, 2A Synchronous Buck-Boost DC/DC Converter
Product Notifications
Please login to your MyLinear account for notifications of datasheet updates, new document releases and LTspice model announcements for your favorite products. If you do not have a MyLinear account you may Sign Up Now.
Forgot your password? Click here.
Need help? Email mylinear@linear.com with questions and comments.
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:
- Step 1: If you have not installed LTspice on this computer, download and install LTspice
- Step 2: Once LTspice is installed, click on the link(s) below to launch the simulation
- Step 3: If LTspice does not automatically open after clicking the link above, 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
To explore other ready to run LTspice demonstration circuits, please visit our Demo Circuits Collection.
Models for the following parts are available in LTspice:
LT3508
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:
LT3508
Technical Support
- For immediate technical assistance, contact your local sales office or distributor or call 1-800-4-LINEAR (US customers only) or 408-432-1900.
- For less urgent requests, please complete our Technical Support Request Form. Please allow 2-3 business days for reply.
