LT3477 - 3A, DC/DC Converter with Dual Rail-to-Rail Current Sense
Features
- Dual 100mV Rail-to-Rail Current Sense Amplifiers
- Wide Input Voltage Range: 2.5V to 25V
- 3A, 42V Internal Switch
- High Efficiency Power Conversion: Up to 93%
- Drives LEDs in Boost, Buck-Boost or Buck Mode
- Frequency Set by External Resistor: 200kHz to 3.5MHz
- Programmable Soft-Start
- Low VCESAT Switch: 0.3V at 2.5A
- Capable of Positive and Negative Output Voltages (Boost, Inverting, SEPIC, Flyback)
- Available in Thermally Enhanced 20-Lead (4mm × 4mm) QFN and 20-Lead TSSOP Packages
AEC-Q100 data available for specific packages
Typical Application
Description
The LT®3477 is a current mode, 3A DC/DC step-up converter with dual rail-to-rail current sense amplifiers and an internal 3A, 42V switch. It combines a traditional voltage feedback loop and two unique current feedback loops to operate as a constant-current, constant-voltage source. Both current sense voltages are set at 100mV and can be adjusted independently using the IADJ1 and IADJ2 pins. Efficiency of up to 93% can be achieved in typical applications. The LT3477 features a programmable soft-start function to limit inductor current during start-up. Both inputs of the error amplifier are available externally allowing positive and negative output voltages (boost, inverting, SEPIC, Flyback). The switching frequency is programmable from 200kHz to 3.5MHz through an external resistor.
Available in thermally enhanced 20-pin (4mm × 4mm) QFN and 20-pin TSSOP packages, the LT3477 provides a complete solution for both constant-voltage and constantcurrent applications.
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 |
|---|---|---|---|---|---|
| LT3477EFE#PBF | TSSOP-20 | FE | E | 05-08-1663 (CB) | Yes |
| LT3477EFE#TRPBF | TSSOP-20 | FE | E | 05-08-1663 (CB) | Yes |
| LT3477EUF#PBF | 4x4 QFN-20 | UF | E | 05-08-1710 | Yes |
| LT3477EUF#TRPBF | 4x4 QFN-20 | UF | E | 05-08-1710 | Yes |
| LT3477IFE#PBF | TSSOP-20 | FE | I | 05-08-1663 (CB) | Yes |
| LT3477IFE#TRPBF | TSSOP-20 | FE | I | 05-08-1663 (CB) | Yes |
| LT3477IUF#PBF | 4x4 QFN-20 | UF | I | 05-08-1710 | Yes |
| LT3477IUF#TRPBF | 4x4 QFN-20 | UF | I | 05-08-1710 | 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 | |
|---|---|---|---|---|---|---|
| LT3477EFE#PBF | TSSOP-20 | E | $4.71 | $3.30 | Yes | |
| LT3477EFE#TRPBF | TSSOP-20 | E | $3.42 | Yes | ||
| LT3477EUF#PBF | 4x4 QFN-20 | E | $4.50 | $3.15 | Yes | |
| LT3477EUF#TRPBF | 4x4 QFN-20 | E | $3.25 | Yes | ||
| LT3477IFE#PBF | TSSOP-20 | I | $5.66 | $3.96 | Yes | |
| LT3477IFE#TRPBF | TSSOP-20 | I | $4.02 | Yes | ||
| LT3477IUF#PBF | 4x4 QFN-20 | I | $5.40 | $3.78 | Yes | |
| LT3477IUF#TRPBF | 4x4 QFN-20 | I | $3.84 | 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 |
|---|---|---|---|
| DC1130A | LT3477EFE/LT3003EMSE | Contact Factory | |
| DC841A | LT3477EFE | Constant Current Boost LED Driver, 2.7V ≤ VIN ≤ 16V, VLED up to 36V @ 330mA | $100.00 | |
| Buy Now | |||
Designed for Automotive and Transportation Applications
AEC-Q100 data is available for these specific part numbers. Please contact your local sales representative for more information regarding reliability reports or to inquire about parts that are not included. For more information, view our Automotive and Transportation page
| Part Number | Package | Temp | Price (1-99) |
Price (1k)* |
RoHS | |
|---|---|---|---|---|---|---|
| LT3477IFE#PBF | TSSOP-20 | I | $5.66 | $3.96 | Yes | |
| LT3477IFE#TRPBF | TSSOP-20 | I | $4.02 | Yes | ||
| Buy Now • Request Samples | ||||||
Applications
- High Power LED Driver
- DSL Modems
- Distributed Power
- Input/Output Current Limited Boost, SEPIC, Inverting, Flyback Converters
- Constant-Voltage, Constant-Current Source
People Who Viewed This Product Also Viewed
- LT3478 - 4.5A Monolithic LED Drivers with True Color PWM Dimming
- LT1618 - Constant-Current/Constant-Voltage 1.4MHz Step-Up DC/DC Converter
- LT3796/LT3796-1 - 100V Constant-Current and Constant-Voltage Controller with Dual Current Sense
- LT3518 - Full-Featured LED Driver with 2.3A Switch Current
- LTM8042/LTM8042-1 - μModule (Power Module) Boost LED Driver and Current Source
- LT3517 - Full-Featured LED Driver with 1.5A Switch Current
- LT3761/LT3761-1 - 60VIN LED Controller with Internal PWM Generator
- LTC3783 - PWM LED Driver and Boost, Flyback and SEPIC Converter
- LT3080 - Adjustable 1.1A Single Resistor Low Dropout Regulator
- LTC3115-1 - 40V, 2A Synchronous Buck-Boost DC/DC Converter
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
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:
LT3477
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.
