LT8609/LT8609A - 42V, 2A/3A Peak Synchronous Step-Down Regulator with 2.5μA Quiescent Current

Features

  • Wide Input Voltage Range: 3.0V to 42V
  • Ultralow Quiescent Current Burst Mode® Operation:
  • <2.5μA IQ Regulating 12VIN to 3.3VOUT
  • Output Ripple <10mVP-P
  • High Efficiency 2MHz Synchronous Operation:
  • >93% Efficiency at 1A, 5VOUT from 12VIN
  • 2A Maximum Continuous Output, 3A Peak Transient Output
  • Fast Minimum Switch-On Time: 45ns
  • Adjustable and Synchronizable: 200kHz to 2.2MHz
  • Spread Spectrum Frequency Modulation for Low EMI
  • Allows Use of Small Inductors
  • Low Dropout
  • Peak Current Mode Operation
  • Accurate 1V Enable Pin Threshold
  • Internal Compensation
  • Output Soft-Start and Tracking
  • Small 10-Lead MSOP Package
Designed for Automotive and Transportation Applications
AEC-Q100 data available for specific packages


Typical Application

LT8609 Typical Application
LT8609 Typical Application

Description

The LT®8609/8609A is a compact, high efficiency, high speed synchronous monolithic step-down switching regulator that consumes only 1.7μA of non-switching quiescent current. The LT8609/LT8609A can deliver 2A of continuous current with peak loads of 3A (<1sec) to support applications such as GSM transceivers which require high transient loads. Top and bottom power switches are included with all necessary circuitry to minimize the need for external components. Low ripple Burst Mode operation enables high efficiency down to very low output currents while keeping the output ripple below 10mVP-P. A SYNC pin allows synchronization to an external clock, or spread spectrum modulation of switching frequencies for low EMI operation. Internal compensation with peak current mode topology allows the use of small inductors and results in fast transient response and good loop stability. The EN/ UV pin has an accurate 1V threshold and can be used to program VIN undervoltage lockout or to shut down the LT8609/LT8609A reducing the input supply current to 1μA. A capacitor on the TR/SS pin programs the output voltage ramp rate during start-up while the PG flag signals when VOUT is within ±8.5% of the programmed output voltage as well as fault conditions. The LT8609/LT8609A is available in a small 10-lead MSOP package. The LT8609A has slower switch edges for lower EMI emissions.

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
LT8609AEMSE#PBF MS-10E MSE E 05-08-1664 Yes
LT8609AEMSE#TRPBF MS-10E MSE E 05-08-1664 Yes
LT8609AIMSE#PBF MS-10E MSE I 05-08-1664 Yes
LT8609AIMSE#TRPBF MS-10E MSE I 05-08-1664 Yes
LT8609EMSE#PBF MS-10E MSE E 05-08-1664 Yes
LT8609EMSE#TRPBF MS-10E MSE E 05-08-1664 Yes
LT8609HMSE#PBF MS-10E MSE H 05-08-1664 Yes
LT8609HMSE#TRPBF MS-10E MSE H 05-08-1664 Yes
LT8609IMSE#PBF MS-10E MSE I 05-08-1664 Yes
LT8609IMSE#TRPBF MS-10E MSE I 05-08-1664 Yes


LT8609 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
LT8609AEMSE#PBF MS-10E E $3.57 $2.50 Yes
LT8609AEMSE#TRPBF MS-10E E $3.63 $2.56 Yes
LT8609AIMSE#PBF MS-10E I $3.93 $2.75 Yes
LT8609AIMSE#TRPBF MS-10E I $3.99 $2.81 Yes
LT8609EMSE#PBF MS-10E E $3.57 $2.50 Yes
LT8609EMSE#TRPBF MS-10E E $2.56 Yes
LT8609HMSE#PBF MS-10E H $4.29 $3.00 Yes
LT8609HMSE#TRPBF MS-10E H $3.06 Yes
LT8609IMSE#PBF MS-10E I $3.93 $2.75 Yes
LT8609IMSE#TRPBF MS-10E I $2.81 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
DC2195A LT8609EMSE Demo Board | µPower Sync Buck, 5.5V ≤ VIN ≤ 42V, 5Vout at 2A, FSW=2MHz Contact Factory
DC2195B-A LT8609AEMSE Demo Board | µPower Sync Buck, Low EMI, 5.5V ≤ VIN ≤ 42V, Vout = 5V @ 2A, FSW = 2MHz Contact Factory
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
LT8609HMSE#PBF MS-10E H $4.29 $3.00 Yes
LT8609HMSE#TRPBF MS-10E H $3.06 Yes
LT8609IMSE#PBF MS-10E I $3.93 $2.75 Yes
LT8609IMSE#TRPBF MS-10E I $2.81 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

  • General Purpose Step Down
  • Low EMI Step Down

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

LTspiceIV

LTspice® IV 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 IV

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 IV
  • Step 2: Once LTspice is installed, click on the link(s) below to launch the simulation
  • Step 3: If LTspice IV 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 IV:
LT8609
LT8609A

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

To open the project file for this circuit:

  • Step 1: If you have not installed LTpowerCAD on this computer, download and install LTpowerCAD
  • Step 2: Once LTpowerCAD is installed, click on the link(s) below to open the project file
  • Step 3: If LTpowerCAD does not automatically open after clicking the link above, you can open the project file by right clicking on the link and selecting "Save Target As." After saving the file to your computer, start LTpowerCAD and open the project file by selecting 'Open Project' from the 'File' menu

Design tools for the following parts are available in LTpowerCAD:
LT8609
LT8609A

Technical Support