LTC3720 - Single Phase VRM8.5 Current Mode Step-Down Controller
Features
- 5-Bit Programmable Output Voltage: 1.05V to 1.825V (VRM8.5)
- No Sense Resistor Required
- 2% to 87% Duty Cycle at 200kHz
- tON(MIN) <= 100ns
- Supports Active Voltage Positioning
- True Current Mode Control
- Stable with Ceramic COUT
- Dual N-Channel MOSFET Synchronous Drive
- Power Good Output Voltage Monitor
- Wide VIN Range: 4V to 36V
- ±1% 0.8V Reference
- Adjustable Current Limit
- Adjustable Switching Frequency
- Forced Continuous Control Pin
- Programmable Soft-Start
- Output Overvoltage Protection
- Optional Short-Circuit Shutdown Timer
- Micropower Shutdown: IQ < 30µA
- Available in 28-Lead Narrow SSOP Package
Typical Application
Description
The LTC3720 is a synchronous step-down switching regulator controller for CPU power. An output voltage between 1.05V and 1.825V is selected by a 5-bit code (Intel VRM8.5 VID specification). The controller uses a valley current control architecture to deliver very low duty cycles without requiring a sense resistor. Operating frequency is selected by an external resistor and is compensated for variations in VIN and VOUT.
Discontinuous mode operation provides high efficiency operation at light loads. A forced continuous control pin reduces noise and RF interference and can assist secondary winding regulation by disabling discontinuous mode operation when the main output is lightly loaded.
Fault protection is provided by internal foldback current limiting, 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 also user programmable. Wide supply range allows operation from 4V to 36V at the input.
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 |
|---|---|---|---|---|---|
| LTC3720EGN#PBF | SSOP-28 | GN | E | 05-08-1641 (GN28) | Yes |
| LTC3720EGN#TRPBF | SSOP-28 | GN | E | 05-08-1641 (GN28) | 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 | |
|---|---|---|---|---|---|---|
| LTC3720EGN#PBF | SSOP-28 | E | $4.64 | $3.05 | Yes | |
| LTC3720EGN#TRPBF | SSOP-28 | E | $3.15 | 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 |
|---|---|---|---|
| DC483A | LTC3720EGN | VRM 8.5 Processor Power Supply, 7.5V to 21Vin, 1.05V to 1.825Vout @ 20A | Contact Factory | |
| Buy Now | |||
Applications
- Power Supplies for Pentium® Processors
- Notebook Computers and Servers
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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:
LTC3720
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.
