LTC3406B - 1.5MHz, 600mA Synchronous Step-Down Regulator in ThinSOT


  • High Efficiency: Up to 96%
  • 600mA Output Current at VIN = 3V
  • 2.5V to 5.5V Input Voltage Range
  • 1.5MHz Constant Frequency Operation
  • No Schottky Diode Required
  • Low Dropout Operation: 100% Duty Cycle
  • Low Quiescent Current: 300µA
  • 0.6V Reference Allows Low Output Voltages
  • Shutdown Mode Draws <1µA Supply Current
  • Current Mode Operation for Excellent Line and Load Transient Response
  • Overtemperature Protected
  • Low Profile (1mm) ThinSOT™ Package

Typical Application

LTC3406B Typical Application
LTC3406B Typical Application


The LTC3406B is a high efficiency monolithic synchronous buck regulator using a constant frequency, current mode architecture. The device is available in an adjustable version and fixed output voltages of 1.5V and 1.8V. Supply current with no load is 300µA and drops to <1µA in shutdown. The 2.5V to 5.5V input voltage range makes the LTC3406B ideally suited for single Li-Ion battery-powered applications. 100% duty cycle provides low dropout operation, extending battery life in portable systems. PWM pulse skipping mode operation provides very low output ripple voltage for noise sensitive applications.

Switching frequency is internally set at 1.5MHz, allowing the use of small surface mount inductors and capacitors. The internal synchronous switch increases efficiency and eliminates the need for an external Schottky diode. Low output voltages are easily supported with the 0.6V feedback reference voltage. The LTC3406B is available in a low profile (1mm) ThinSOT package. Refer to LTC3406 for applications that require Burst Mode® operation.

Protected by U.S. Patents, including 6580258, 5481178.

  Vout Fsw Features
LTC3406 Adj. 1.5MHz  Burst Mode
LTC3406-1.2 1.2V 1.5MHz   Burst Mode
LTC3406-1.5 1.5V 1.5MHz  Burst Mode
LTC3406-1.8 1.8V 1.5MHz  Burst Mode
LTC3406B Adj. 1.5MHz Burst Mode Disabled
LTC3406B-1.2 1.2V 1.5MHz Burst Mode Disabled
LTC3406B-2 Adj. 2.25MHz Burst Mode Disabled
LTC3406A Adj. 1.5MHz Low Ripple Burst Mode
LTC3406AB Adj. 1.5MHz Burst Mode Disabled
LTC3406AB-2 Adj. 2.25MHz Burst Mode Disabled


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
LTC3406BES5-1.5#TRMPBF SOT-23 S5 E 05-08-1635 Yes
LTC3406BES5-1.5#TRPBF SOT-23 S5 E 05-08-1635 Yes
LTC3406BES5-1.8#TRMPBF SOT-23 S5 E 05-08-1635 Yes
LTC3406BES5-1.8#TRPBF SOT-23 S5 E 05-08-1635 Yes
LTC3406BES5#TRMPBF SOT-23 S5 E 05-08-1635 Yes
LTC3406BES5#TRPBF SOT-23 S5 E 05-08-1635 Yes

LTC3406B Package Drawing
LTC3406B 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
LTC3406BES5-1.5#TRMPBF SOT-23 E $2.86 $2.03 Yes
LTC3406BES5-1.5#TRPBF SOT-23 E $2.86 $2.01 Yes
LTC3406BES5-1.8#TRMPBF SOT-23 E $2.86 $2.03 Yes
LTC3406BES5-1.8#TRPBF SOT-23 E $2.86 $2.01 Yes
LTC3406BES5#TRMPBF SOT-23 E $2.86 $2.03 Yes
LTC3406BES5#TRPBF SOT-23 E $2.86 $2.01 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
DC500A-D LTC3406BES5 Demo Board | 2.7V to 5.5Vin, 1.2Vout @ 600mA(max) $75.00
DC500A-E LTC3406BES5-1.5 Demo Board | 2.7V to 5.5Vin, 1.5Vout @ 600mA(max) $75.00
DC500A-F LTC3406BES5-1.8 Demo Board | 2.7V to 5.5Vin, 1.8Vout @ 600mA(max) $75.00
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Click here to view our complete list of demo boards


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  • Portable Instruments

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Design Tools


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