LTC3878 - Fast, Wide Operating Range No RSENSE Step-Down DC/DC Controller


  • Wide VIN Range: 4V to 38V
  • ±1% 0.8V Voltage Reference
  • Extremely Fast Transient Response
  • tON(MIN): 43ns
  • No RSENSE™ Valley Current Mode Control
  • Stable with Low ESR Ceramic COUT
  • Supports Smooth Start-Up Into Pre-Biased Output
  • Optimized for High Step-Down Ratios
  • Pin Compatible with the LTC1778 (No EXTVCC Pin)
  • Power Good Output Voltage Monitor
  • Dual N-Channel MOSFET Synchronous Drive
  • Adjustable Switching Frequency
  • Programmable Current Limit with Foldback
  • Output Overvoltage Protection
  • Small 16-Pin Narrow SSOP Package

Typical Application

LTC3878 Typical Application
LTC3878 Typical Application


The LTC3878 is a synchronous step-down switching DC/DC controller optimized for high switching frequency and fast transient response. The constant on-time valley current mode architecture allows for a wide input range, including very low duty factor operation. No external sense resistor or slope compensation is required. The LTC3878 is pin compatible with the LTC1778 in applications that do not use EXTVCC while offering better efficiency. Consult with the factory to verify compatibility.

Operating frequency is set by an external resistor and compensated for variations in VIN to offer excellent line stability. Discontinuous mode operation provides high efficiency during light load conditions. A forced continuous control pin allows the user to reduce noise and RF interference. Safety features include output overvoltage protection and programmable current limit with foldback. Soft-start capability for supply sequencing is accomplished through an external timing capacitor. The current limit is user programmable.

The LTC3878 allows operation from 4V to 38V at the input and from 0.8V to 90% VIN at the output. The LTC3878 is available in a small 16-pin narrow SSOP package.


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
LTC3878EGN#PBF SSOP-16 GN E 05-08-1641 (GN16) Yes
LTC3878EGN#TRPBF SSOP-16 GN E 05-08-1641 (GN16) Yes
LTC3878IGN#PBF SSOP-16 GN I 05-08-1641 (GN16) Yes
LTC3878IGN#TRPBF SSOP-16 GN I 05-08-1641 (GN16) Yes

LTC3878 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
LTC3878EGN#PBF SSOP-16 E $2.44 $1.71 Yes
LTC3878EGN#TRPBF SSOP-16 E $1.77 Yes
LTC3878IGN#PBF SSOP-16 I $2.77 $1.94 Yes
LTC3878IGN#TRPBF SSOP-16 I $2.00 Yes
Buy NowRequest Samples
* 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
DC1292A LTC3878EGN Demo Board | No Rsense, 4.5V ≤ VIN ≤ 14V, Vout = 1.2V @ 18A $125.00
Buy Now
Click here to view our complete list of demo boards


  • Distributed Power Systems
  • Embedded Computing
  • Communications Infrastructure

Product Notifications

Please login to your MyLinear account for notifications of datasheet updates, new document releases and LTspice model announcements for your favorite products. If you do not have a MyLinear account you may Sign Up Now.

Forgot your password? Click here.
Need help? Email with questions and comments.

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

To launch a ready to run LTspice demonstration circuit for this part:

  • Step 1: If you have not installed LTspice on this computer, download and install LTspice
  • Step 2: Once LTspice is installed, click on the link(s) below to launch the simulation
  • Step 3: If LTspice does not automatically open after clicking the link above, you can instead run the simulation by right clicking on the link and selecting "Save Target As." After saving the file to your computer, start LTspice and open the demonstration circuit by selecting 'Open' from the 'File' menu

To explore other ready to run LTspice demonstration circuits, please visit our Demo Circuits Collection.

Models for the following parts are available in LTspice:

Technical Support