LTC1709-7 - 2-Phase, 5-Bit VID, Current Mode, High Efficiency, Synchronous Step-Down Switching Regulator
Features
- Output Stages Operate Antiphase Reducing Input Capacitance Requirements and Power Supply Induced Noise
- Dual Input Supply Capability for Load Sharing
- 5-Bit Mobile VID Code: VOUT = 0.925V to 2V
- Current Mode Control Ensures Current Sharing
- True Remote Sensing Differential Amplifier
- Power Good Output Indicator
- OPTI-LOOP™ Compensation Minimizes COUT
- Three Operational Modes: PWM, Burst and Cycle Skip
- Programmable Fixed Frequency: 150kHz to 300kHz
- ±1% Output Voltage Accuracy
- Wide VIN Range: 4V to 36V Operation
- Adjustable Soft-Start Current Ramping
- Internal Current Foldback and Short-Circuit Shutdown
- Overvoltage Soft Latch Eliminates Nuisance Trips
- Active Voltage Positioning Capable
- Available in 36-Lead Narrow SSOP Package
Typical Application
Description
The LTC1709-7 is a 2-phase, VID programmable, synchronous step-down switching regulator controller that drives two all N-channel external power MOSFET stages in a fixed frequency architecture. The 2-phase controller drives its two output stages out of phase at frequencies up to 300kHz to minimize the RMS ripple currents in both input and output capacitors. The 2-phase technique effectively multiplies the fundamental frequency by two, improving transient response while operating each channel at an optimum frequency for efficiency. Thermal design is also simplified.
An operating mode select pin (FCB) can be used to regulate a secondary winding or select among three modes including Burst Mode™ operation for highest efficiency. An internal differential amplifier provides true remote sensing of the regulated supply’s positive and negative output terminals as required in high current applications.
The RUN/SS pin provides 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 for a wide range of output capacitors and ESR values.
| Vout Range |
VRM | |
| LTC1709 | 1.3V to 3.5V | VRM8.4 |
| LTC1709-7 | 0.925V to 2V | Mobile |
| LTC1709-8 | 1.3V to 3.5V | VRM8.4 |
| LTC1709-8.5 | 1.05V to 1.825V | VRM8.5 |
| LTC1709-9 | 1.1V to 1.85V | VRM9.0 |
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 |
|---|---|---|---|---|---|
| LTC1709EG-7#PBF | SSOP-36 | G | E | 05-08-1640 (G36) | Yes |
| LTC1709EG-7#TRPBF | SSOP-36 | G | E | 05-08-1640 (G36) | 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 | |
|---|---|---|---|---|---|---|
| LTC1709EG-7#PBF | SSOP-36 | E | $5.60 | $4.75 | Yes | |
| LTC1709EG-7#TRPBF | SSOP-36 | E | $4.85 | 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 |
|---|---|---|---|
| DC292B-A | LTC1709EG-7 | High Current Mobile CPU Power Supply, 12Vin, 1.6Vout @ 30A, (all Surface Mount Caps) | Contact Factory | |
| Buy Now | |||
Applications
- Mobile/Desktop Computers
- Internet Servers
- Large Memory Arrays
- DC Power Distribution Systems
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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:
LTC1709
LTC1709-7
LTC1709-8
LTC1709-85
LTC1709-9
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.
