LTC3708 - Fast 2-Phase, No RSENSE Buck Controller with Output Tracking
Features
- Very Low Duty Factor Operation
(tON(MIN) < 85ns) - No RSENSE™ Option for Maximum Efficiency
- Very Fast Transient Response
- Programmable Output Voltage Up/Down Tracking
- 2-Phase Operation Reduces Input Capacitance
- 0.6V ±1% Output Voltage Reference
- External Frequency Synchronization
- Monotonic Soft-Start
- Onboard High Current MOSFET Drivers
- Wide VIN Range: Up to 36V
- Adjustable Cycle-by-Cycle Current Limit
- Instant Output Overvoltage Protection
- Optional Short-Circuit Shutdown Timer
- Power Good Output with 100µs Masking
- Available in 5mm x 5mm QFN Package
Typical Application
Description
The LTC3708 is a dual, 2-phase synchronous step-down switching regulator with output voltage up/down tracking capability. The IC allows either coincident or ratiometric tracking. Multiple LTC3708s can be daisy-chained in applications requiring more than two voltages to be tracked. Power supply sequencing is accomplished using an external soft-start timing capacitor.
The LTC3708 uses a constant on-time, valley current mode control architecture to deliver very low duty factors without requiring a sense resistor. Operating frequency is selected by an external resistor and is compensated for variations in input supply voltage. An internal phase-locked loop allows the IC to be synchronized to an external clock.
Fault protection is provided by an output overvoltage comparator and an optional short-circuit shutdown timer. The regulator current limit level is user programmable. A wide supply range allows voltages as high as 36V to be stepped down to 0.6V output.
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 |
|---|---|---|---|---|---|
| LTC3708EUH#PBF | 5x5 QFN-32 | UH | E | 05-08-1693 | Yes |
| LTC3708EUH#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 | |
|---|---|---|---|---|---|---|
| LTC3708EUH#PBF | 5x5 QFN-32 | E | $5.71 | $4.80 | Yes | |
| LTC3708EUH#TRPBF | 5x5 QFN-32 | E | $4.90 | 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.Click here to view our complete list of demo boards
Applications
- Notebook and Palmtop Computers, PDAs
- Digital Signal Processors
- Network 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:
LTC3708
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.
