LTC1909-8 - Wide Operating Range, No RSENSE Step-Down DC/DC Controller with SMBus Programming
Features
- SMBus/I²C™ Programmable Output Voltage: 1.3V to 3.5V
- No Sense Resistor Required
- 2% to 90% Duty Cycle at 200kHz
- tON(MIN) </= 100ns
- True Current Mode Control
- Stable with Ceramic COUT
- Power Good Output Voltage Monitor and 50µs Timer
- Wide VIN Range: 4V to 36V (Abs Max)
- Precision Resistor Divider and Reference Provide ±1.35% Output Voltage Accuracy Over Temperature
- Adjustable Switching Frequency and Current Limit
- Forced Continuous Control Pin
- Programmable Soft-Start
- Output Overvoltage Protection
- Optional Short-Circuit Shutdown Timer
- Available in a 28-Lead SSOP Package
Typical Application
Description
The LTC1909-8 is a synchronous step-down switching regulator controller with a digitally programmable output voltage. The output voltage is selected from one of two 5-bit settings programmed into internal registers via a 2-wire SMBus/I²C interface. The interface features safeguards against invalid output voltages and allows the microprocessor to turn the regulator on and off. Valley current control delivers 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.
The LTC1909-8 is available in the 28-lead SSOP package.
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 |
|---|---|---|---|---|---|
| LTC1909-8EG#PBF | SSOP-28 | G | E | 05-08-1640 (G28) | Yes |
| LTC1909-8EG#TRPBF | SSOP-28 | G | E | 05-08-1640 (G28) | 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 | |
|---|---|---|---|---|---|---|
| LTC1909-8EG#PBF | SSOP-28 | E | $5.98 | $5.05 | Yes | |
| LTC1909-8EG#TRPBF | SSOP-28 | E | $5.15 | 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 |
|---|---|---|---|
| DC475A | LTC1909-8EG | SMBus Controlled DC/DC Converter, Vin = 7.5V-21V, Vout = 1.3V-3.5V@10A | Contact Factory | |
| Buy Now | |||
Applications
- Power Supplies for DSPs, ASICs, FPGAs and CPUs
- Voltage Margining
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Design Tools
Linear Technology provides a variety of custom design simulation tools and device models to allow even novice designers to quickly and easily evaluate circuits using high performance switching regulators, amplifiers, data converters, filters and more. Please visit our Design Tools page to view and download:
- LTspice - A powerful SPICE simulator, schematic capture and waveform viewer with enhancements and models for easing the simulation of switching regulators
- LTpowerCAD - A complete power supply selection, synthesis and design tool
- LTpowerPlay - A development environment supporting Linear Technology's Digital Power System Management (PSM) products
- PScope & QuikEval - USB-based product demonstration and data acquisition system for use with our ADCs, DACs, and more
- Linduino - Arduino compatible system for developing and distributing firmware libraries and example code
- LinearLab Tools - A collection of Matlab and Python programs that provide direct access to Linear Technology’s data converter evaluation boards
- And More!
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.
