LTC3718 - Low Input Voltage, DC/DC Controller for DDR/QDR Memory Termination

Features

  • Very Low VIN(MIN): 1.5V
  • Ultrafast Transient Response
  • True Current Mode Control
  • 5V Drive for N-Channel MOSFETs Eliminates Auxillary 5V Supply
  • No Sense Resistor Required
  • Uses Standard 5V Logic-Level N-Channel MOSFETs
  • VOUT(MIN): 0.4V
  • VOUT Tracks 1/2 VIN or External VREF
  • Symmetrical Source and Sink Output Current Limit
  • Adjustable Switching Frequency
  • tON(MIN) <100ns
  • Power Good Output Voltage Monitor
  • Programmable Soft-Start
  • Output Overvoltage Protection
  • Optional Short-Circuit Shutdown Timer
  • Small 24-Lead SSOP Package

Typical Application

LTC3718 Typical Application
LTC3718 Typical Application

Description

The LTC3718 is a high current, high efficiency synchronous switching regulator controller for DDR and QDR™ memory termination. It operates from an input as low as 1.5V and provides a regulated output voltage equal to (0.5)VIN. The controller uses a valley current control architecture to enable high frequency operation with very low on-times without requiring a sense resistor. Operating frequency is selected by an external resistor and is compensated for variations in VIN and VOUT. The LTC3718 uses a pair of standard 5V logic level N-channel external MOSFETs, eliminating the need for expensive P-channel or low threshold devices.

Forced continuous operation reduces noise and RF interference. Fault protection is provided by internal foldback current limiting, an output overvoltage comparator and an optional short-circuit timer. Soft-start capability for supply sequencing can be accomplished using an external timing capacitor. OPTI-LOOP® compensation allows the transient response to be optimized over a wide range of loads and output capacitors.

OPTI-LOOP is a registered trademark of Linear Technology Corporation. No RSENSE is a trademark of Linear Technology Corporation. QDR RAMs and Quad Data Rate RAMs comprise a new family of products developed by Cypress Semiconductor, IDT and Micron Technology, Inc.

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
LTC3718EG#PBF SSOP-24 G E 05-08-1640 (G24) Yes
LTC3718EG#TRPBF SSOP-24 G E 05-08-1640 (G24) Yes


LTC3718 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
LTC3718EG#PBF SSOP-24 E $4.91 $3.45 Yes
LTC3718EG#TRPBF SSOP-24 E $3.55 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
DC464A LTC3718EG | Low Input Voltage, High Current, DDR Termination Supply, 1.5-5Vin, VRef/2 @ 0-12a Contact Factory
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Click here to view our complete list of demo boards

Applications

  • Bus Termination: DDR/QDR Memory, SSTL, HSTL,...
  • Servers, RAID Systems
  • Distributed Power Systems
  • Synchronous Buck with General Purpose Boost

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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

Models for the following parts are available in LTspice:
LTC3718

Technical Support