LTC3729 - 550kHz, PolyPhase, High Efficiency, Synchronous Step-Down Switching Regulator
Features
- Wide VIN Range: 4V to 36V Operation
- Reduces Required Input Capacitance and Power Supply Induced Noise
- ±1% Output Voltage Accuracy
- Phase-Lockable Fixed Frequency: 250kHz to 550kHz
- True Remote Sensing Differential Amplifier
- PolyPhase™ Extends from Two to Twelve Phases
- Reduces the Size and Value of Inductors
- Current Mode Control Ensures Current Sharing
- 1.1MHz Effective Switching Frequency (2-Phase)
- OPTI-LOOP™ Compensation Reduces COUT
- Power Good Output Voltage Indicator
- Very Low Dropout Operation: 99% Duty Cycle
- Adjustable Soft-Start Current Ramping
- Internal Current Foldback Plus Shutdown Timer
- Overvoltage Soft-Latch Eliminates Nuisance Trips
- Available in 5mm x 5mm QFN and 28-Lead SSOP Package
Typical Application
Description
The LTC3729 is a multiple phase, synchronous step-down current mode switching regulator controller that drives N-channel external power MOSFET stages in a phase-lockable fixed frequency architecture. The PolyPhase controller drives its two output stages out of phase at frequencies up to 550kHz to minimize the RMS ripple currents in both input and output capacitors. The output clock signal allows expansion for up to 12 evenly phased controllers for systems requiring 15A to 200A of output current. The multiple phase technique effectively multiplies the fundamental frequency by the number of channels used, improving transient response while operating each channel at an optimum frequency for efficiency. Thermal design is also simplified.
An internal differential amplifier provides true remote sensing of the regulated supply’s positive and negative output terminals as required for high current applications.
A RUN/SS pin provides both soft-start and optional timed, short-circuit shutdown. Current foldback limits MOSFET dissipation during short-circuit conditions when the overcurrent latchoff is disabled. OPTI-LOOP compensation allows the transient response to be optimized over a wide range of output capacitance and ESR values. The LTC3729 includes a power good output pin that indicates when the output is within ±7.5% of the designed set point.
| Vin Max |
Vref |
|
| LTC3729 | 36V | 0.8 |
| LTC3729L-6 | 30V | 0.6 |
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 |
|---|---|---|---|---|---|
| LTC3729EG#PBF | SSOP-28 | G | E | 05-08-1640 (G28) | Yes |
| LTC3729EG#TRPBF | SSOP-28 | G | E | 05-08-1640 (G28) | Yes |
| LTC3729EUH#PBF | 5x5 QFN-32 | UH | E | 05-08-1693 | Yes |
| LTC3729EUH#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 | |
|---|---|---|---|---|---|---|
| LTC3729EG#PBF | SSOP-28 | E | $6.86 | $5.80 | Yes | |
| LTC3729EG#TRPBF | SSOP-28 | E | $5.90 | Yes | ||
| LTC3729EUH#PBF | 5x5 QFN-32 | E | $8.66 | $5.90 | Yes | |
| LTC3729EUH#TRPBF | 5x5 QFN-32 | E | $6.00 | 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 |
|---|---|---|---|
| DC509B | LTC3729EUH Demo Board | 5V to 14VIN, 2.5V@25A VOUT | $175.00 | |
| Buy Now | |||
Applications
- Desktop Computers
- Large Memory Arrays
- DC Power Distribution Systems
People Who Viewed This Product Also Viewed
- LT8705 - 80V VIN and VOUT Synchronous 4-Switch Buck- Boost DC/DC Controller
- LT3796/LT3796-1 - 100V Constant-Current and Constant-Voltage Controller with Dual Current Sense
- LTC3789 - High Efficiency, Synchronous, 4-Switch Buck-Boost Controller
- LTC4000 - High Voltage High Current Controller for Battery Charging and Power Management
- LTC3731 - 3-Phase, 600kHz, Synchronous Buck Switching Regulator Controller
- LTC3829 - 3-Phase, Single Output Synchronous Step-Down DC/DC Controller with Diffamp
- LT3080 - Adjustable 1.1A Single Resistor Low Dropout Regulator
- LT4320/LT4320-1 - Ideal Diode Bridge Controller
- LTC3786 - Low IQ Synchronous Boost Controller
- LTC3703 - 100V Synchronous Switching Regulator Controller
Product Notifications
Please login to your MyLinear account for notifications of datasheet updates, new document releases and LTspice model announcements for your favorite products. If you do not have a MyLinear account you may Sign Up Now.
Forgot your password? Click here.
Need help? Email mylinear@linear.com with questions and comments.
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:
LTC3729
LTC3729L-6
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.
