LTC3733 - 3-Phase, Buck Controllers for AMD CPUs
Features
- 3-Phase Controller with Onboard MOSFET Drivers
- Current Mode Control Ensures Current Sharing
- Differential Amplifier Accurately Senses VOUT
- ±5% Output Current Matching Optimizes Thermal Performance and Size of Inductors and MOSFETs
- Reduced Input and Output Capacitance
- Supports Active Voltage Positioning
- VID Programmable Output Voltage from 0.8V to 1.55V (AMD Opteron™ CPU)
- 6-Phase, 90A to 120A Operation
- Output Power Good Indicator with Adaptive Blanking
- 210kHz to 530kHz Per Phase, PLL, Fixed Frequency
- Synchronizable (LTC3733-1)
- PWM, Stage Shedding or Burst Mode® Operation
- OPTI-LOOP® Compensation Minimizes COUT
- Adjustable Soft-Start Current Ramping
- Short-Circuit Shutdown Timer with Defeat Option
- No_CPU Detection
- 36-Lead Narrow SSOP and 38-Lead (5mm x 7mm) QFN
Typical Application
Description
The LTC3733 family are PolyPhase synchronous stepdown switching regulator controllers that drive all N-channel external power MOSFET stages in a phaselockable, fixed frequency architecture. The 3-phase controller drives its output stages with 120° phase separation at frequencies of up to 530kHz per phase to minimize the RMS current dissipated by the ESR of both the input and output filter capacitors. The 3-phase technique effectively triples the fundamental frequency, improving transient response while operating each phase at an optimal frequency for efficiency and ease of thermal design. Light load efficiency is optimized by using a choice of output stage shedding or Burst Mode technology.
A differential amplifier provides true remote sensing of both the high and low sides of the output voltage at load points. Soft-start and a defeatable, timed short-circuit shutdown protect the MOSFETs and the load. A foldback current circuit also provides protection for the external MOSFETs under short-circuit or overload conditions. An all-“1” VID detector turns off the regulator after 1µs timeout.
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 |
|---|---|---|---|---|---|
| LTC3733CG#PBF | SSOP-36 | G | C | 05-08-1640 (G36) | Yes |
| LTC3733CG#TRPBF | SSOP-36 | G | C | 05-08-1640 (G36) | Yes |
| LTC3733CUHF-1#PBF | 5x7 QFN-38 | UHF | C | 05-08-1701 | Yes |
| LTC3733CUHF-1#TRPBF | 5x7 QFN-38 | UHF | C | 05-08-1701 | 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 | |
|---|---|---|---|---|---|---|
| LTC3733CG#PBF | SSOP-36 | C | $6.25 | $4.35 | Yes | |
| LTC3733CG#TRPBF | SSOP-36 | C | $4.45 | Yes | ||
| LTC3733CUHF-1#PBF | 5x7 QFN-38 | C | $6.70 | $4.65 | Yes | |
| LTC3733CUHF-1#TRPBF | 5x7 QFN-38 | C | $4.75 | 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 |
|---|---|---|---|
| DC648A | LTC3733CG Demo Board | 3-Phase, AMD Hammer Processor Power Supply, Vin = 7V to 21V, Vout = 0.8V to 1.55V @ 65A | Contact Factory | |
| Buy Now | |||
Applications
- High Performance Notebook Computers
- Servers, Desktop Computers and Workstations
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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:
LTC3733
LTC3733-1
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.
