RH3845 – Radiation Hardened High Voltage Synchronous Current Mode Step-Down Controller with Adjustable Operating Frequency


  • Processed in Compliance with LTC Certified MIL-PRF-38535 Class V Flow
  • High Voltage Operation: Up to 60V
  • Output Voltages Up to 36V
  • Synchronizable Up to 600kHz
  • Adjustable Constant Frequency:  - 100kHz to 500kHz
  • 100μA Shutdown Supply Current
  • Capable of Driving Large Power MOSFETs
  • Short-Circuit Protection and Soft-Start

Radiation Performance

  • Total Ionizing Dose (TID) Tolerance, per TM1019.8, MIL-STD-883:
    - 200kRad (Si), per condition A at 50Rads(Si)/sec
    - 100kRad (Si), per condition D at 10mRads(Si)/sec
    - ELDRS Pass 100kRad(Si)
  • Displacement Damage Defect (DDD) up to 1E12 Neutrons/cm2
  • Single Event Transient (SET), Single Event Upset (SEU) and Single Event Latchup (SEL) tests up to a Linear Energy Transfer (LET) of 117.6 MeV.cm2 /mg to case temperatures of 100°C

Typical Application

RH3845MK Typical Application


The RH3845 is a high voltage, synchronous, current mode controller used for medium to high power, high efficiency supplies. It offers a wide 4V to 60V input range (7.5V minimum start-up voltage). An onboard regulator simplifies the biasing requirements by providing IC power directly from VIN.

Light load efficiency is also improved with the reverse inductor current inhibit function which supports discontinuous operation.  BurstMode® is not available in the space version of the part

Additional features include adjustable fixed operating frequency that can be synchronized to an external clock for noise sensitive applications, gate drivers capable of driving large N-channel MOSFETs, a precision undervoltage lockout, short-circuit protection and a programmable soft-start.

Third Party Vendor Availability

Linear Technology partners with third party vendors who assemble and test packaged products with LTC RH Dice inside

Part Number Description SMD
MSK5055RH High Voltage Switching Controller (RH3845A IC only) 5962-14223
MSK5063RH 10A ,60V DC-DC Buck Regulator Module (External Inductor) -


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

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

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.

Click here to view our complete list of demo boards


  • Intermediate Bus Power Supplies
  • Avionics and Control Systems
  • Distributed Power Converters

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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


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

Technical Support