LT8611 - 42V, 2.5A Synchronous Step-Down Regulator with Current Sense and 2.5μA Quiescent Current
Features
- Rail-to-Rail Current Sense Amplifier with Monitor
- Wide Input Voltage Range: 3.4V to 42V
- Ultralow Quiescent Current Burst Mode® Operation:
2.5μA IQ Regulating 12VIN to 3.3VOUT
Output Ripple < 10mVP-P - High Efficiency Synchronous Operation:
96% Efficiency at 1A, 5VOUT from 12VIN
94% Efficiency at 1A, 3.3VOUT from 12VIN - Fast Minimum Switch-On Time: 50ns
- Low Dropout Under All Conditions: 200mV at 1A
- Allows Use Of Small Inductors
- Low EMI
- Adjustable and Synchronizable: 200kHz to 2.2MHz
- Current Mode Operation
- Accurate 1V Enable Pin Threshold
- Internal Compensation
- Output Soft-Start and Tracking
- Small Thermally Enhanced 3mm × 5mm 24-Lead QFN Package
AEC-Q100 data available for specific packages
Typical Application
Description
The LT®8611 is a compact, high efficiency, high speed synchronous monolithic step-down switching regulator that consumes only 2.5μA of quiescent current. Top and bottom power switches are included with all necessary circuitry to minimize the need for external components. The built-in current sense amplifier with monitor and control pins allows accurate input or output current regulation and limiting. 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. 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 LT8611 reducing the input supply current to 1μA. A capacitor on the TR/SS pin programs the output voltage ramp rate during start-up. The PG flag signals when VOUT is within ±9% of the programmed output voltage as well as fault conditions. The LT8611 is available in a small 24-lead 3mm × 5mm QFN package with exposed pad for low thermal resistance.
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 |
|---|---|---|---|---|---|
| LT8611EUDD#PBF | 3x5 QFN-24 | UDD | E | 05-08-1833 | Yes |
| LT8611EUDD#TRPBF | 3x5 QFN-24 | UDD | E | 05-08-1833 | Yes |
| LT8611IUDD#PBF | 3x5 QFN-24 | UDD | I | 05-08-1833 | Yes |
| LT8611IUDD#TRPBF | 3x5 QFN-24 | UDD | I | 05-08-1833 | 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 | |
|---|---|---|---|---|---|---|
| LT8611EUDD#PBF | 3x5 QFN-24 | E | $5.43 | $3.80 | Yes | |
| LT8611EUDD#TRPBF | 3x5 QFN-24 | E | $3.86 | Yes | ||
| LT8611IUDD#PBF | 3x5 QFN-24 | I | $5.94 | $4.16 | Yes | |
| LT8611IUDD#TRPBF | 3x5 QFN-24 | I | $4.22 | 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 |
|---|---|---|---|
| DC1750A | LT8611 Demo Board | Micropower Sync Buck with Current Sense, 3.8V ≤ VIN ≤ 42V, Vout = 3.3V @ 2.5A | $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 | |
|---|---|---|---|---|---|---|
| LT8611IUDD#PBF | 3x5 QFN-24 | I | $5.94 | $4.16 | Yes | |
| LT8611IUDD#TRPBF | 3x5 QFN-24 | I | $4.22 | Yes | ||
| Buy Now • Request Samples | ||||||
Applications
- Automotive and Industrial Supplies
- General Purpose Step-Down
- CCCV Power Supplies
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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:
LT8611
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:
LT8611
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.
