LT8303 - 100Vin Micropower Isolated Flyback Converter with 150V/450mA Switch


  • 5.5V to 100V Input Voltage Range
  • 450mA, 150V Internal DMOS Power Switch
  • Up to 5W of Output Power
  • Low Quiescent Current:
     70μA in Sleep Mode
     280μA in Active Mode
  • Boundary Mode Operation at Heavy Load
  • Low-Ripple Burst Mode® Operation at Light Load
  • Minimum Load <0.5% (Typ) of Full Output
  • VOUT Set with a Single External Resistor
  • No Transformer Third Winding or Opto-Isolator
  • Required for Regulation
  • Accurate EN/UVLO Threshold and Hysteresis
  • Internal Compensation and Soft-Start
  • 5-Lead TSOT-23 Package

Typical Application

LT8303 Typical Application
LT8303 Typical Application


The LT8303 is a micropower high voltage isolated flyback converter. By sampling the isolated output voltage directly from the primary-side flyback waveform, the part requires no third winding or opto-isolator for regulation. The output voltage is programmed with a single external resistor. Internal compensation and soft-start further reduce external component count. Boundary mode operation provides a small magnetic solution with excellent load regulation. Low ripple Burst Mode operation maintains high efficiency at light load while minimizing the output voltage ripple. A 450mA, 150V DMOS power switch is integrated along with all high voltage circuitry and control logic into a 5-lead thinSOT™ package.

The LT8303 operates from an input voltages range of 5.5V to 100V and can deliver up to 5W of isolated output power. The high level of integration and the use of boundary and low ripple burst modes result in a simple to use, low component count, and high efficiency application solution for isolated power delivery.


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
LT8303ES5#PBF SOT-23 S5 E 05-08-1635 Yes
LT8303ES5#TRMPBF SOT-23 S5 E 05-08-1635 Yes
LT8303ES5#TRPBF SOT-23 S5 E 05-08-1635 Yes
LT8303HS5#PBF SOT-23 S5 H 05-08-1635 Yes
LT8303HS5#TRMPBF SOT-23 S5 H 05-08-1635 Yes
LT8303HS5#TRPBF SOT-23 S5 H 05-08-1635 Yes
LT8303IS5#PBF SOT-23 S5 I 05-08-1635 Yes
LT8303IS5#TRMPBF SOT-23 S5 I 05-08-1635 Yes
LT8303IS5#TRPBF SOT-23 S5 I 05-08-1635 Yes

LT8303 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
LT8303ES5#PBF SOT-23 E $4.50 Yes
LT8303ES5#TRMPBF SOT-23 E $4.50 $3.20 Yes
LT8303ES5#TRPBF SOT-23 E $4.50 $3.15 Yes
LT8303HS5#PBF SOT-23 H $5.22 Yes
LT8303HS5#TRMPBF SOT-23 H $5.22 $3.70 Yes
LT8303HS5#TRPBF SOT-23 H $5.22 $3.65 Yes
LT8303IS5#PBF SOT-23 I $4.79 Yes
LT8303IS5#TRMPBF SOT-23 I $4.79 $3.40 Yes
LT8303IS5#TRPBF SOT-23 I $4.79 $3.35 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
DC2490A LT8303ES5 Isolated Demo Board | No-Opto Flyback, 36V ≤ VIN ≤ 72V, VOUT = 5V @ up to 0.84A $125.00
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Click here to view our complete list of demo boards


  • Isolated Telecom, Datacom, Automotive, Industrial, and Medical Power Supplies
  • Isolated Auxiliary/Housekeeping Power Supplies

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Design Tools


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