LT8611 - 42V, 2.5A Synchronous Step-Down Regulator with Current Sense and 2.5μA Quiescent Current


  • 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

Typical Application

LT8611 Typical Application
LT8611 Typical Application


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.


For complete and up to date package information and drawings, please refer to our packaging page

3x5 QFN-24

LT8611 Package Drawing

Order Info

Package Variations and Pricing

Part Number Package Pins Temp Price (1-99) Price (1k)* RoHS Data
LT8611EUDD#PBF QFN 24 E $5.43 $3.80 View
LT8611EUDD#TRPBF QFN 24 E $3.86 View
LT8611IUDD#PBF QFN 24 I $5.94 $4.16 View
LT8611IUDD#TRPBF QFN 24 I $4.22 View
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* 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
DC1750A LT8611 Demo Board | Micropower Sync Buck with Current Sense, 3.8V ≤ VIN ≤ 42V, Vout = 3.3V @ 2.5A $125.00
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Click here to view our complete list of demo boards


  • Automotive and Industrial Supplies
  • General Purpose Step-Down
  • CCCV Power Supplies

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