RH1959 - Radiation Hardened 4.5A, 500kHz Step-Down Switching Regulator


  • MIL-PRF-38535 Class V Compatible Dice *
  • Operates with Input as Low as 4V
  • Output Voltages Down to 1.21V
  • Constant 500kHz Switching Frequency
  • Synchronizable to 1MHz
  • Internal Slope Compensation
  • Cycle-by-Cycle Current Limiting
  • Integrated 4.5A Switch
  • Current Mode Control

Radiation Performance*

  • Total Ionizing Dose (TID) Tolerance, per TM1019.8, MIL-STD-883:
    - 100kRad (Si), per condition A at 50Rads(Si)/sec
    - 50kRad (Si), per condition D at 10mRads(Si)/sec
    - ELDRS Pass 50kRad(Si)
  • Displacement Damage Defect (DDD) up to 1E12 Neutrons/cm2
  • Single Event Performance up to an LET of at least 80 MeVcm2/mg

* Radiation and Qualification completed on the packaging vendor’s assembled unit.

Typical Application

RH1959 Typical Application


The RH1959 is a 500kHz monolithic buck mode switching regulator with a 4.5A integrated switch that will operate down to 1.21V. High switching frequency allows a considerable reduction in the size of external components. The topology is current mode for fast transient response and good loop stability.

A special high speed bipolar process and new design techniques achieve high efficiency at high switching frequency. Efficiency is maintained over a wide output current range by keeping quiescent supply current near 3.3mA and by utilizing a supply boost capacitor to saturate the power switch.

Full cycle-by-cycle short-circuit protection and thermal shutdown are provided. Standard surface mount external parts are used, including the inductor and capacitors. Optional shutdown and synchronization functions are available. Implementing shutdown reduces supply current to 30μA. Synchronization allows an external logic level signal to increase the internal oscillator from 580kHz to 1MHz.

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
MSK5044RH Switching Reg. Module,500kHz Fixed Frequency 5962-11231
MSK5048RH Switching Reg. Module,500kHz With Ext Sync Opt 5962-11232
MSK5052RH Switching Reg. Module,500kHz With Ext Sync Opt -
MSK5059RH Switching Reg. Monolithic (RH1959 IC Only) 5962-11234


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.

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  • High Efficiency Low Voltage Subsystem Power Supply

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