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
AEC-Q100 data available for specific packages
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 |
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 Now • Request Samples | ||||||
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 | |||
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 Now • Request Samples | ||||||
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
- For immediate technical assistance, contact your local sales office or distributor or call 1-800-4-LINEAR (US customers only) or 408-432-1900.
- For less urgent requests, please complete our Technical Support Request Form. Please allow 2-3 business days for reply.
