LTC3770 - Fast No RSENSE Step-Down Synchronous Controller with Margining, Tracking and PLL
Features
- Wide VIN Range: 4V to 32V
- ±0.67% 0.6V Reference Voltage
- Output Voltage Tracking Capability
- Programmable Margining
- Sense Resistor Optional
- True Current Mode Control
- 2% to 90% Duty Cycle at 200kHz
- tON(MIN) ≤ 100ns
- Phase Lock Loop Frequency Synchronization
- Powerful Dual N-Channel MOSFET Driver
- Adjustable Cycle-by-Cycle Current Limit
- Adjustable Switching Frequency
- Programmable Soft-Start
- Current Foldback Protection (Disabled at Start-Up)
- Output Overvoltage Protection
- Micropower Shutdown: IQ < 30µA
- Power Good Output Voltage Monitor Tracks the Reference Input Pin
- Available in (5mm × 5mm) QFN and 28-Lead SSOP Packages
Typical Application
Description
The LTC3770 is a synchronous step-down switching regulator controller with output voltage up/down tracking capability and voltage margining. Its advanced functions and high accuracy reference are ideal for powering high performance server, ASIC and computer memory systems.
The LTC3770 uses a constant on-time, valley current mode control architecture to deliver very low duty factors without requiring a sense resistor. The operating frequency is selected by an external resistor and is compensated for variations in input supply voltage. An internal phase-lock loop allows the IC to be synchronized to an external clock.
Fault protection is provided by an overvoltage comparator and input undervoltage lockout. The regulator current limit is user programmable. A wide supply range allows voltages as high as 32V to be stepped down to as low as a 0.6V output. Power supply sequencing is accomplished using an external soft-start timing capacitor.
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 |
|---|---|---|---|---|---|
| LTC3770EG#PBF | SSOP-28 | G | E | 05-08-1640 (G28) | Yes |
| LTC3770EG#TRPBF | SSOP-28 | G | E | 05-08-1640 (G28) | Yes |
| LTC3770EUH#PBF | 5x5 QFN-32 | UH | E | 05-08-1693 | Yes |
| LTC3770EUH#TRPBF | 5x5 QFN-32 | UH | E | 05-08-1693 | 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 | |
|---|---|---|---|---|---|---|
| LTC3770EG#PBF | SSOP-28 | E | $4.23 | $3.55 | Yes | |
| LTC3770EG#TRPBF | SSOP-28 | E | $3.65 | Yes | ||
| LTC3770EUH#PBF | 5x5 QFN-32 | E | $4.23 | $3.55 | Yes | |
| LTC3770EUH#TRPBF | 5x5 QFN-32 | E | $3.65 | 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 |
|---|---|---|---|
| DC774A | LTC3770EUF Demo Board | Margining & Tracking, 5V ≤ VIN ≤ 28V, Vout = 2.5V @ 10A | $125.00 | |
| Buy Now | |||
Applications
- Distributed Power Systems
- Server Power Supply
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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
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
- Step 2: Once LTspice is installed, click on the link(s) below to launch the simulation
- Step 3: If LTspice 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.
Models for the following parts are available in LTspice:
LTC3770
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.
