LTC3717-1 - Wide Operating Range, No RSENSE Step-Down Controller for DDR/QDR Memory Termination

Features

  • VOUT = 1/2 VREF
  • Adjustable and Symmetrical Sink/Source Current Limit up to 20A
  • True Current Mode Control with Optional Use of Sense Resistor
  • VON and ION Pins Allow Constant Frequency Operation During Input and Output Voltage Changes
  • ±0.65% Output Voltage Accuracy
  • Up to 97% Efficiency
  • Ultrafast Transient Response
  • 2% to 90% Duty Cycle at 200kHz
  • tON(MIN) </= 100ns
  • Stable with Ceramic COUT
  • Power Good Output Voltage Monitor
  • Wide VIN Range: 4V to 36V
  • Adjustable Switching Frequency up to 1.5MHz
  • Output Overvoltage Protection
  • Optional Short-Circuit Shutdown Timer
  • Available in a 5mm x 5mm QFN Package

Typical Application

LTC3717-1 Typical Application
LTC3717-1 Typical Application

Description

The LTC3717-1 is a synchronous step-down switching regulator controller for double data rate (DDR) and Quad Data Rate (QDR) memory termination. The controller uses a valley current control architecture to deliver very low duty cycles with or without a sense resistor. Operating frequency is selected by an external resistor and is compensated for variations in VIN and VOUT.

Forced continuous operation reduces noise and RF interference. Output voltage is internally set to half of VREF, which is user programmable.

Fault protection is provided by 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 symmetrical and user programmable. Wide supply range allows operation from 4V to 36V at the VCC input.

  Von Pin
Package
LTC3717 No SSOP-16
LTC3717-1 Yes QFN-32

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
LTC3717EUH-1#PBF 5x5 QFN-32 UH E 05-08-1693 Yes
LTC3717EUH-1#TRPBF 5x5 QFN-32 UH E 05-08-1693 Yes


LTC3717-1 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
LTC3717EUH-1#PBF 5x5 QFN-32 E $4.73 $3.15 Yes
LTC3717EUH-1#TRPBF 5x5 QFN-32 E $3.25 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.

Click here to view our complete list of demo boards

Applications

  • Bus Termination: DDR and QDR Memory, SSTL, HSTL, ...
  • Notebook Computers, Desktop Servers
  • Tracking/Margining Power Supply

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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:
LTC3717
LTC3717-1

Technical Support