Power Management
Switching Regulator
Step-Down (Buck) Regulators
Multiple Output Buck
Power Management
Switching Regulator
DDR Memory/Bus Termination
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
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 fi rst 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
For complete and up to date package information and drawings, please refer to our packaging page
QFN-24, TSSOP-24
Order Info
- Part numbers ending in PBF are lead free. Please contact LTC marketing for information on lead based finish parts.
- 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 | Pins | Temp | Price (1-99) | Price (1k)* | RoHS Data |
|---|---|---|---|---|---|---|
| LTC3618EFE#PBF | TSSOP | 24 | E | $6.07 | $4.25 | View |
| LTC3618EFE#TRPBF | TSSOP | 24 | E | $4.31 | View | |
| LTC3618EUF#PBF | QFN | 24 | E | $5.86 | $4.10 | View |
| LTC3618EUF#TRPBF | QFN | 24 | E | $4.16 | View | |
| LTC3618IFE#PBF | TSSOP | 24 | I | $6.71 | $4.70 | View |
| LTC3618IFE#TRPBF | TSSOP | 24 | I | $4.76 | View | |
| LTC3618IUF#PBF | QFN | 24 | I | $6.43 | $4.50 | View |
| LTC3618IUF#TRPBF | QFN | 24 | I | $4.56 | View | |
| Buy Now • Request Samples | ||||||
Demo Boards
Linear Technology demo boards are offered free of charge to qualified customers. Contact your local sales office or distributor to request 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 u Dual 3A Synchronous Buck Regulator for DDR Termination | Contact Factory | |
| Buy Now | |||
Applications
- DDR Memory Termination
- Supports DDR, DDR2, and DDR3 Standards
- Tracking Supplies
Simulate
LTspice IV is a powerful, fast and free simulation tool, schematic capture and waveform viewer with enhancements and models for improving the simulation of switching regulators. To download LTspice IV and other FREE simulation tools, please visit our Design Simulation page.
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 IV
- Step 2: Once LTspice is installed, click on the link(s) below to launch the simulation
- Step 3: If LTspice IV 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.
Related models available in LTspice IV
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.
