LTC7821 - Hybrid Step-Down Synchronous Controller


  • Wide VIN Range: 10V to 72V (80V ABS Max)
  • Soft Switching for Low Noise Operation
  • Phase-Lockable Fixed Frequency 200kHz to 1.5MHz
  • ±1% Output Voltage Accuracy
  • RSENSE or DCR Current Sensing
  • Programmable CCM, DCM, or Burst Mode® Operation
  • CLKOUT Pin for Multiphase Operation
  • Short Circuit Protected
  • EXTVCC Input for Improved Efficiency
  • Monotonic Output Voltage Start-Up
  • Optional External Reference
  • 32-Pin (5mm × 5mm) QFN

Typical Application

LTC7821 Typical Application
LTC7821 Typical Application


The LTC®7821 uses a proprietary architecture that merges a soft switching charge pump topology with a synchronous step-down converter to provide superior efficiency and EMI performance compared to traditional switching architectures.

In a typical 48V to 12V application, efficiency of greater than 97% is attainable with the LTC7821 switching at 500kHz. The same efficiency can only be achieved with a traditional controller switching at one-third the frequency. Higher switching frequencies allow the use of smaller inductances that yield faster transient response and smaller solution size.

The LTC7821 can be easily paralleled to provide higher output currents with its accurate current sharing capability and frequency synchronization function.



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

Part Number Package Code Temp Package
LTC7821EUH#PBF 5x5 QFN-32 UH E 05-08-1693 Yes
LTC7821EUH#TRPBF 5x5 QFN-32 UH E 05-08-1693 Yes
LTC7821IUH#PBF 5x5 QFN-32 UH I 05-08-1693 Yes
LTC7821IUH#TRPBF 5x5 QFN-32 UH I 05-08-1693 Yes

LTC7821 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
LTC7821EUH#PBF 5x5 QFN-32 E $7.43 $5.20 Yes
LTC7821EUH#TRPBF 5x5 QFN-32 E $7.49 $5.26 Yes
LTC7821IUH#PBF 5x5 QFN-32 I $8.22 $5.75 Yes
LTC7821IUH#TRPBF 5x5 QFN-32 I $8.28 $5.81 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
DC2513A LTC7821EUH Demo Board | 36V ≤ VIN ≤ 72V; VOUT = 12V @ 20A, 97.5% Efficiency/500kHz Contact Factory
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Click here to view our complete list of demo boards


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