LTC1625 - No RSENSE Current Mode Synchronous Step-Down Switching Regulator

Features

  • Highest Efficiency Current Mode Controller
  • No Sense Resistor Required
  • Stable High Current Operation
  • Dual N-Channel MOSFET Synchronous Drive
  • Wide VIN Range: 3.7V to 36V
  • Wide VOUT Range: 1.19V to VIN
  • ±1% 1.19V Reference
  • Programmable Fixed Frequency with Injection Lock
  • Very Low Drop Out Operation: 99% Duty Cycle
  • Forced Continuous Mode Control Pin
  • Optional Programmable Soft Start
  • Pin Selectable Output Voltage
  • Foldback Current Limit
  • Output Overvoltage Protection
  • Logic Controlled Micropower Shutdown: IQ < 30µA
  • Available in 16-Lead Narrow SSOP and SO Packages
Designed for Automotive and Transportation Applications
AEC-Q100 generic family data available for specific packages


Typical Application

LTC1625 Typical Application
LTC1625 Typical Application

Description

The LTC1625 is a synchronous step-down switching regulator controller that drives external N-Channel power MOSFETs using few external components. Current mode control with MOSFET VDS sensing eliminates the need for a sense resistor and improves efficiency. The frequency of a nominal 150kHz internal oscillator can be synchronized to an external clock over a 1.5:1 frequency range.

Burst Mode operation at low load currents reduces switching losses and low dropout operation extends operating time in battery-powered systems. A forced continuous mode control pin can assist secondary winding regulation by disabling Burst Mode operation when the main output is lightly loaded.

Fault protection is provided by foldback current limiting and an output overvoltage comparator. An external capacitor attached to the RUN/SS pin provides soft start capability for supply sequencing. A wide supply range allows operation from 3.7V (3.9V for LTC1625I) to 36V at the input and 1.19V to 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
LTC1625CGN#PBF SSOP-16 GN C 05-08-1641 (GN16) Yes
LTC1625CGN#TRPBF SSOP-16 GN C 05-08-1641 (GN16) Yes
LTC1625CS#PBF SO-16 S C 05-08-1610 (S16) Yes
LTC1625CS#TRPBF SO-16 S C 05-08-1610 (S16) Yes
LTC1625IGN#PBF SSOP-16 GN I 05-08-1641 (GN16) Yes
LTC1625IGN#TRPBF SSOP-16 GN I 05-08-1641 (GN16) Yes
LTC1625IS#PBF SO-16 S I 05-08-1610 (S16) Yes
LTC1625IS#TRPBF SO-16 S I 05-08-1610 (S16) Yes


LTC1625 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
LTC1625CGN#PBF SSOP-16 C $5.80 $4.90 Yes
LTC1625CGN#TRPBF SSOP-16 C $4.96 Yes
LTC1625CS#PBF SO-16 C $5.45 $4.55 Yes
LTC1625CS#TRPBF SO-16 C $4.61 Yes
LTC1625IGN#PBF SSOP-16 I $7.02 $5.90 Yes
LTC1625IGN#TRPBF SSOP-16 I $5.96 Yes
LTC1625IS#PBF SO-16 I $6.75 $5.50 Yes
LTC1625IS#TRPBF SO-16 I $5.56 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
DC2008A LTC1625IGN Demo Board | 4.5V ≤ VIN ≤ 28V; VOUT = 3.3V @ 15A Contact Factory
Buy Now
Click here to view our complete list of demo boards

Designed for Automotive and Transportation Applications

Please contact your local sales representative for more information regarding reliability reports and AEC-Q100 data 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
LTC1625IGN#PBF SSOP-16 I $7.02 $5.90 Yes
LTC1625IGN#TRPBF SSOP-16 I $5.96 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
  • Cellular Telephones and Wireless Modems
  • Battery Chargers
  • Distributed Power

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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:
LTC1625

Technical Support