LTC3618 - Dual 4MHz, ±3A Synchronous Buck Converter for DDR Termination

Features

  • DDR Power Supply, Termination and Reference
  • High Efficiency: Up to 94%
  • Dual Outputs with ±3A Output Current Capability
  • 2.25V to 5.5V Input Voltage Range
  • ±1% Output Voltage Accuracy
  • VTT Output Voltage Down to 0.5V
  • Shutdown Current ≤1μA
  • VTTR = VDDQIN/2, VFB2 = VTTR
  • Adjustable Switching Frequency Up to 4MHz
  • Internal or External Compensation
  • Selectable 0°/90°/180° Phase Shift Between Channels
  • Internal or External Soft-Start for VDDQ, Internal Soft-Start for VTT
  • Power Good Status Outputs
  • Low Profile 4mm × 4mm QFN-24 and TSSOP-24 Packages
Designed for Automotive and Transportation Applications
AEC-Q100 data available for specific packages


Typical Application

LTC3618 Typical Application
LTC3618 Typical Application

Description

The LTC®3618 is a dual synchronous step-down regulator using a current mode, constant-frequency architecture. It provides a complete DDR solution with an input voltage range from 2.25V to 5.5V.

The output of the first step-down regulator offers a high accuracy VDDQ supply. A buffered reference generates VTTR at 50% of VDDQIN and drives loads up to ±10mA. The second regulator generates the DDR termination voltage (VTT) equal to VTTR. Both regulators are capable of delivering ±3A of load current at 1MHz switching frequency.

The operating frequency is externally programmable up to 4MHz, allowing the use of small surface mount inductors. 0°, 90°, or 180° of phase shift between the two channels can be selected to minimize input current ripple. For switching noise-sensitive applications, the LTC3618 can be synchronized to an external clock up to 4MHz.

The LTC3618 is offered in leadless 24-pin 4mm × 4mm QFN and thermally enhanced 24-pin TSSOP packages.

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
LTC3618EFE#PBF TSSOP-24 FE E 05-08-1771 Yes
LTC3618EFE#TRPBF TSSOP-24 FE E 05-08-1771 Yes
LTC3618EUF#PBF 4x4 QFN-24 UF E 05-08-1697 Yes
LTC3618EUF#TRPBF 4x4 QFN-24 UF E 05-08-1697 Yes
LTC3618IFE#PBF TSSOP-24 FE I 05-08-1771 Yes
LTC3618IFE#TRPBF TSSOP-24 FE I 05-08-1771 Yes
LTC3618IUF#PBF 4x4 QFN-24 UF I 05-08-1697 Yes
LTC3618IUF#TRPBF 4x4 QFN-24 UF I 05-08-1697 Yes


LTC3618 Package Drawing
LTC3618 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
LTC3618EFE#PBF TSSOP-24 E $6.07 $4.25 Yes
LTC3618EFE#TRPBF TSSOP-24 E $4.31 Yes
LTC3618EUF#PBF 4x4 QFN-24 E $5.86 $4.10 Yes
LTC3618EUF#TRPBF 4x4 QFN-24 E $4.16 Yes
LTC3618IFE#PBF TSSOP-24 I $6.71 $4.70 Yes
LTC3618IFE#TRPBF TSSOP-24 I $4.76 Yes
LTC3618IUF#PBF 4x4 QFN-24 I $6.43 $4.50 Yes
LTC3618IUF#TRPBF 4x4 QFN-24 I $4.56 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
DC1726A LTC3618EUF Demo Board | For DDR Termination, 2.25V ≤ VIN ≤ 5.5V, VDDQ = 1.5V/1.8V/2.5V @ ±3A, VTT = 0.5VDDQ @ ±3A, VTTR Current = ±10mA $150.00
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
LTC3618IFE#PBF TSSOP-24 I $6.71 $4.70 Yes
LTC3618IFE#TRPBF TSSOP-24 I $4.76 Yes
LTC3618IUF#PBF 4x4 QFN-24 I $6.43 $4.50 Yes
LTC3618IUF#TRPBF 4x4 QFN-24 I $4.56 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.

Applications

  • DDR Memory
  • Supports DDR, DDR2, and DDR3 Standards
  • Tracking Supplies

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Design Tools

LTspice

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LTC3618

Technical Support