LT1765 - Monolithic 3A, 1.25MHz Step-Down Switching Regulators


  • 3A Switch in a Thermally Enhanced 16-Lead TSSOP or 8-Lead SO Package
  • Constant 1.25MHz Switching Frequency
  • Wide Operating Voltage Range: 3V to 25V
  • High Efficiency 0.09Ω Switch
  • 1.2V Feedback Reference Voltage
  • Uses Low Profile Surface Mount Components
  • Low Shutdown Current: 15µA
  • Synchronizable to 2MHz
  • Current Mode Loop Control
  • Constant Maximum Switch Current Rating at All Duty Cycles*
  • Available in 8-Lead SO and 16-Lead Thermally Enhanced TSSOP Packages

Typical Application

LT1765 Typical Application
LT1765 Typical Application


The LT1765 is a 1.25MHz monolithic buck switching regulator. A high efficiency 3A, 0.09Ω switch is included on the die together with all the control circuitry required to construct a high frequency, current mode switching regulator. Current mode control provides fast transient response and excellent loop stability.

New design techniques achieve high efficiency at high switching frequencies over a wide operating voltage range. A low dropout internal regulator maintains consistent performance over a wide range of inputs from 24V systems to Li-Ion batteries. An operating supply current of 1mA improves efficiency, especially at lower output currents. Shutdown reduces quiescent current to 15µA. Maximum switch current remains constant at all duty cycles. Synchronization allows an external logic level signal to increase the internal oscillator into the range of 1.6MHz to 2MHz.

Full cycle-by-cycle current control and thermal shutdown are provided. High frequency operation allows the reduction of input and output filtering components and permits the use of chip inductors.


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
LT1765EFE-1.8#PBF TSSOP-16 FE E 05-08-1663 (BB) Yes
LT1765EFE-1.8#TRPBF TSSOP-16 FE E 05-08-1663 (BB) Yes
LT1765EFE-2.5#PBF TSSOP-16 FE E 05-08-1663 (BB) Yes
LT1765EFE-2.5#TRPBF TSSOP-16 FE E 05-08-1663 (BB) Yes
LT1765EFE-3.3#PBF TSSOP-16 FE E 05-08-1663 (BB) Yes
LT1765EFE-3.3#TRPBF TSSOP-16 FE E 05-08-1663 (BB) Yes
LT1765EFE-5#PBF TSSOP-16 FE E 05-08-1663 (BB) Yes
LT1765EFE-5#TRPBF TSSOP-16 FE E 05-08-1663 (BB) Yes
LT1765EFE#PBF TSSOP-16 FE E 05-08-1663 (BB) Yes
LT1765EFE#TRPBF TSSOP-16 FE E 05-08-1663 (BB) Yes
LT1765ES8#PBF SO-8 S8 E 05-08-1610 (S8) Yes
LT1765ES8#TRPBF SO-8 S8 E 05-08-1610 (S8) Yes

LT1765 Package Drawing
LT1765 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
LT1765EFE-1.8#PBF TSSOP-16 E $6.89 $4.82 Yes
LT1765EFE-1.8#TRPBF TSSOP-16 E $4.94 Yes
LT1765EFE-2.5#PBF TSSOP-16 E $6.89 $4.82 Yes
LT1765EFE-2.5#TRPBF TSSOP-16 E $4.94 Yes
LT1765EFE-3.3#PBF TSSOP-16 E $6.89 $4.82 Yes
LT1765EFE-3.3#TRPBF TSSOP-16 E $4.94 Yes
LT1765EFE-5#PBF TSSOP-16 E $6.89 $4.82 Yes
LT1765EFE-5#TRPBF TSSOP-16 E $4.94 Yes
LT1765EFE#PBF TSSOP-16 E $6.89 $4.82 Yes
LT1765EFE#TRPBF TSSOP-16 E $4.94 Yes
LT1765ES8#PBF SO-8 E $5.53 $4.67 Yes
LT1765ES8#TRPBF SO-8 E $4.73 Yes
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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
DC436A LT1765ES8 | Wide Input Range, 1.25MHz Step-Down DC/DC Converter, 8.5V~25Vin, 5Vout @ 2A $100.00
DC476A LT1765EFE | Wide Input Range, 1.25MHz Step-Down DC/DC Converter, 3V to 25V Input, Jumper Selectable 3.3V or 5Vout @ 2A $100.00
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Click here to view our complete list of demo boards


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Design Tools


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

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