LTC3608 - 18V, 8A Monolithic Synchronous Step-Down DC/DC Converter

Features

  • 8A Output Current
  • Wide VIN Range = 4V to 18V
  • Internal N-Channel MOSFETs
  • True Current Mode Control
  • Optimized for High Step-Down Ratios
  • tON(MIN) ≤ 100nsec
  • Extremely Fast Transient Response
  • Stable with Ceramic COUT
  • ±1% 0.6V Voltage Reference
  • Power Good Output Voltage Monitor
  • Adjustable On-Time/Switching Frequency
  • Adjustable Current Limit
  • Programmable Soft-Start
  • Output Overvoltage Protection
  • Optional Short-Circuit Shutdown Timer
  • Low Shutdown IQ: 15μA
  • Available in a 7mm × 8mm 52-Lead QFN Package
Designed for Automotive and Transportation Applications
AEC-Q100 data available for specific packages


Typical Application

LTC3608 Typical Application
LTC3608 Typical Application

Description

The LTC3608 is a high efficiency, monolithic synchronous step-down DC/DC converter that can deliver up to 8A output current from a 4V to 18V (20V maximum) input supply. It uses a valley current control architecture to deliver very low duty cycle operation at high frequency with excellent transient response. The operating frequency is selected by an external resistor and is compensated for variations in VIN and VOUT.

The LTC3608 can be configured for discontinuous or forced continuous operation at light load. Forced continuous operation reduces noise and RF interference while discontinuous mode provides high efficiency by reducing switching losses at light loads.

Fault protection is provided by internal foldback current limiting, an output overvoltage comparator and an optional short-circuit shutdown timer. Soft-start capability for supply sequencing is accomplished using an external timing capacitor. The regulator current limit is user programmable. A power good output voltage monitor indicates when the output is in regulation. The LTC3608 is available in a compact 7mm × 8mm QFN package.

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
LTC3608EWKG#PBF 7x8 QFN-52 WKG E 05-08-1768 Yes
LTC3608EWKG#TRPBF 7x8 QFN-52 WKG E 05-08-1768 Yes
LTC3608IWKG#PBF 7x8 QFN-52 WKG I 05-08-1768 Yes
LTC3608IWKG#TRPBF 7x8 QFN-52 WKG I 05-08-1768 Yes


LTC3608 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
LTC3608EWKG#PBF 7x8 QFN-52 E $10.70 $7.50 Yes
LTC3608EWKG#TRPBF 7x8 QFN-52 E $7.60 Yes
LTC3608IWKG#PBF 7x8 QFN-52 I $12.33 $8.63 Yes
LTC3608IWKG#TRPBF 7x8 QFN-52 I $8.73 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
DC1320A-A LTC3608EWKG Demo Board | Monolithic, 5V ≤ VIN ≤ 20V, Vout = 1.5V/1.8V/2.5V/3.3V @ 8A $125.00
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
LTC3608IWKG#PBF 7x8 QFN-52 I $12.33 $8.63 Yes
LTC3608IWKG#TRPBF 7x8 QFN-52 I $8.73 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

  • Point of Load Regulation
  • Distributed Power Systems

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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:

  • 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:
LTC3608

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:
LTC3608

Technical Support