LT1777 - Low Noise Step-Down Switching Regulator


  • Programmable dI/dt Limit
  • Internally Limited dV/dt
  • High Input Voltage: 48V Max
  • 700mA Peak Switch Rating
  • True Current Mode Control
  • 100kHz Fixed Operating Frequency
  • Synchronizable to 250kHz
  • Low Supply Current in Shutdown: 30µA
  • Low Thermal Resistance 16-Pin SO Package

Typical Application

LT1777 Typical Application
LT1777 Typical Application


The LT1777 is a Buck (step-down) regulator designed for noise sensitive applications. It contains a dI/dt limiting circuit programmed via a small external inductor in the switching path. Internal circuitry also generates controlled dV/dt ramp rates.

The monolithic die includes all oscillator, control and protection circuitry. The part can accept operating input voltages as high as 48V, and contains an output switch rated at 700mA peak current. Current mode control offers excellent dynamic input supply rejection and short-circuit protection. The internal control circuitry is normally powered via the VCC pin, thereby minimizing power drawn directly from the VIN supply (see Applications Information). The fused-lead SO16 package and 100kHz switching frequency allow for minimal PC board area requirements.


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
LT1777CS#PBF SO-16 S C 05-08-1610 (S16) Yes
LT1777CS#TRPBF SO-16 S C 05-08-1610 (S16) Yes
LT1777IS#PBF SO-16 S I 05-08-1610 (S16) Yes
LT1777IS#TRPBF SO-16 S I 05-08-1610 (S16) Yes

LT1777 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
LT1777CS#PBF SO-16 C $3.10 $2.65 Yes
LT1777CS#TRPBF SO-16 C $2.71 Yes
LT1777IS#PBF SO-16 I $3.75 $3.15 Yes
LT1777IS#TRPBF SO-16 I $3.21 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
DC242A LT1777CS | 100kHz Low Noise DC-DC Converter, 7.4V to 48V Input, 3.3V or 5Vout @ 0.5A $100.00
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Click here to view our complete list of demo boards


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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

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