LTC1778 - Wide Operating Range, No RSENSE Step-Down Controller

Features

  • No Sense Resistor Required
  • True Current Mode Control
  • Optimized for High Step-Down Ratios
  • tON(MIN) <=100ns
  • Extremely Fast Transient Response
  • Stable with Ceramic COUT
  • Dual N-Channel MOSFET Synchronous Drive
  • Power Good Output Voltage Monitor (LTC1778)
  • Adjustable On-Time (LTC1778-1)
  • Wide VIN Range: 4V to 36V
  • ±1% 0.8V Voltage Reference
  • Adjustable Current Limit
  • Adjustable Switching Frequency
  • Programmable Soft-Start
  • Output Overvoltage Protection
  • Optional Short-Circuit Shutdown Timer
  • Micropower Shutdown: IQ <30µA
  • Available in a 16-Pin Narrow SSOP Package
Designed for Automotive and Transportation Applications
AEC-Q100 data available for specific packages


Typical Application

LTC1778 Typical Application
LTC1778 Typical Application

Description

The LTC1778 is a synchronous stepdown switching regulator controller optimized for CPU power. The controller uses a valley current control architecture to deliver very low duty cycles with excellent transient response without requiring a sense resistor. Operating frequency is selected by an external resistor and is compensated for variations in VIN.

Discontinuous mode operation provides high efficiency operation at light loads. A forced continuous control pin reduces noise and RF interference, and can assist secondary winding regulation by disabling discontinuous operation when the main output is lightly loaded.

Fault protection is provided by internal foldback current limiting, an output overvoltage comparator and optional short-circuit shutdown timer. Soft-start capability for supply sequencing is accomplished using an external timing capacitor. The regulator current limit level is user programmable. Wide supply range allows operation from 4V to 36V at the input and from 0.8V up to (0.9)VIN at the output.

Packaging

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
Drawing
RoHS
LTC1778EGN-1#PBF SSOP-16 GN E 05-08-1641 (GN16) Yes
LTC1778EGN-1#TRPBF SSOP-16 GN E 05-08-1641 (GN16) Yes
LTC1778EGN#PBF SSOP-16 GN E 05-08-1641 (GN16) Yes
LTC1778EGN#TRPBF SSOP-16 GN E 05-08-1641 (GN16) Yes
LTC1778IGN#PBF SSOP-16 GN I 05-08-1641 (GN16) Yes
LTC1778IGN#TRPBF SSOP-16 GN I 05-08-1641 (GN16) Yes


LTC1778 Package Drawing
LTC1778 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
(1-99)
Price
(1k)*
RoHS
LTC1778EGN-1#PBF SSOP-16 E $3.07 $2.70 Yes
LTC1778EGN-1#TRPBF SSOP-16 E $2.76 Yes
LTC1778EGN#PBF SSOP-16 E $3.07 $2.70 Yes
LTC1778EGN#TRPBF SSOP-16 E $2.76 Yes
LTC1778IGN#PBF SSOP-16 I $4.43 $3.10 Yes
LTC1778IGN#TRPBF SSOP-16 I $3.16 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
DC378A LTC1778EGN | No Rsense, 5V ≤ VIN ≤ 25V, Vout = 2.5V @ 10A $125.00
DC385A LTC1778EGN Demo Board | IMVPII I/O Power Supply, Vin=5V-25V, Vout=1.2V @ 6A $125.00
Buy Now
Click here to view our complete list of demo boards

Designed for Automotive and Transportation Applications

AEC-Q100 data is available for these specific part numbers. Please contact your local sales representative for more information regarding reliability reports or to inquire about parts that are not included. For more information, view our Automotive and Transportation page

Part Number Package Temp Price
(1-99)
Price
(1k)*
RoHS
LTC1778IGN#PBF SSOP-16 I $4.43 $3.10 Yes
LTC1778IGN#TRPBF SSOP-16 I $3.16 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.

Applications

  • Notebook and Palmtop Computers, PDAs
  • Distributed Power Systems

Product Notifications

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Design Tools

LTspice

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:
LTC1778
LTC1778-1

Technical Support