LTC3873 - No RSENSE Constant Frequency Current Mode Boost/Flyback/SEPIC DC/DC Controller
Features
- VIN and VOUT Limited Only by External Components
- Internal or Programmable External Soft-Start
- Constant Frequency 200kHz Operation
- Adjustable Current Limit
- Current Sense Resistor Optional
- Maximum 60V on SW Node with RDS(ON) Sensing
- ±1.5% Voltage Reference Accuracy
- Current Mode Operation for Excellent Line and Load Transient Response
- Low Quiescent Current: 300µA
- Low Profile (1mm) ThinSOT and (0.75mm) 2mm × 3mm DFN Package
Typical Application
Description
The LTC3873 is a constant frequency, current mode, boost, flyback or SEPIC DC/DC controller that drives an N-channel power MOSFET in high input and output voltage converter applications. Soft-start can be programmed using an external capacitor.
The LTC3873 provides ±1.5% output voltage accuracy and consumes only 300μA quiescent current during normal operation and only 55μA during micropower start-up. Using a 9.3V internal shunt regulator, the LTC3873 can be powered from a high input voltage through a resistor or it can be powered directly from a low impedance DC voltage of 9V or less.
The LTC3873 is available in 8-lead ThinSOT and 2mm x 3mm DFN packages.
| LTC3873 | LTC3873-5 | |
|---|---|---|
| VCC UV+ | 8.4V | 4.1V |
| VCC UV- | 4V | 2.9V |
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 |
|---|---|---|---|---|---|
| LTC3873EDDB#PBF | 3x2 DFN-8 | DDB | E | 05-08-1702 | Yes |
| LTC3873EDDB#TRMPBF | 3x2 DFN-8 | DDB | E | 05-08-1702 | Yes |
| LTC3873EDDB#TRPBF | 3x2 DFN-8 | DDB | E | 05-08-1702 | Yes |
| LTC3873ETS8#PBF | SOT-23 | TS8 | E | 05-08-1637 | Yes |
| LTC3873ETS8#TRMPBF | SOT-23 | TS8 | E | 05-08-1637 | Yes |
| LTC3873ETS8#TRPBF | SOT-23 | TS8 | E | 05-08-1637 | 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 | |
|---|---|---|---|---|---|---|
| LTC3873EDDB#PBF | 3x2 DFN-8 | E | $1.79 | Yes | ||
| LTC3873EDDB#TRMPBF | 3x2 DFN-8 | E | $1.79 | $1.30 | Yes | |
| LTC3873EDDB#TRPBF | 3x2 DFN-8 | E | $1.79 | $1.25 | Yes | |
| LTC3873ETS8#PBF | SOT-23 | E | $1.79 | Yes | ||
| LTC3873ETS8#TRMPBF | SOT-23 | E | $1.79 | $1.30 | Yes | |
| LTC3873ETS8#TRPBF | SOT-23 | E | $1.79 | $1.25 | 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 |
|---|---|---|---|
| DC1154A | LTC3873ETS8 Isolated/Non-Isolated Demo Board | 36 ≤ Vin ≤ 72V, Vout: 3.3V/3A | $75.00 | |
| Buy Now | |||
Applications
- Telecom Power Supplies
- 42V and 12V Automotive Power Supplies
- Portable Electronic Equipment
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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:
LTC3873
LTC3873-5
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.
