LT3909
2-String × 60mA, 2MHz Step-Up LED Driver with ±2% Current Matching
Top
Overview
Features and Benefits
- Up to 36V of LEDs, 2-String × 60mA LED Driver
- Wide Input Range: 2.9V to 40V
- Up to 40,000:1 PWM Dimming (250ns LED On-Time) (Independent of Leakage at VOUT)
- ±2% LED Current Matching (Typ ±0.3%)
- Integrated Schottky Diode
- Internal 400mΩ, 40V, 1A Switch
- Single Resistor Sets LED Current (10mA to 60mA) for Both High-Side Current Sources
- Output Adapts to LED VF for Optimum Efficiency
- LED Current Regulated Even for VIN > VOUT
- Fault Flag + Protection for Open-LED and LED-Short-to- GND (Other String Remains in Regulation)
- Programmable Maximum VOUT (Regulated)
- Internal Compensation, Soft-Start and Thermal Regulation
- Accurate EN/UVLO Threshold
- Fixed 2MHz Switching Frequency
Product Details
The LT3909 is a 2-string × 60mA LED driver with a fixed 2MHz step-up DC/DC converter capable of driving up to 36V of LEDs. Each LED string contains an accurate high-side current source with ±2% current matching. Output voltage adapts to variations in LED VF for optimum efficiency.
Maximum LED current can be programmed from 10mA to 60mA per string using a single resistor. LED brightness can be reduced with analog dimming (up to 10:1) or with PWM dimming (up to 40,000:1 at 100Hz, up to 160:1 at 25kHz) (independent of leakage at VOUT). The LED pins can be paralleled for higher LED current.
Additional features include: programmable maximum VOUT for open LED protection, a fault flag to indicate open-LED or LED-short-to-GND and an internal regulation loop to safely limit junction temperature. The LT3909 also includes internal compensation, internal soft-start and micropower shutdown. The LT3909 is available in the 12-pin (3mm × 3mm) DFN and 12-pin MSOP packages.
Applications
- PDAs, Handheld Computers
- GPS Receivers
- Automotive Displays
- High Contrast Instrument Clusters
Product Categories
Markets and Technologies
Product Lifecycle
Recommended for New Designs
This product has been released to the market. The data sheet contains all final specifications and operating conditions. For new designs, ADI recommends utilization of these products.
Evaluation Kits (1)
Documentation & Resources
-
R580 Reliability Data4/17/2019
-
DC2176A - Demo Manual5/27/2016
Tools & Simulations
LTspice
LTspice® is a powerful, fast and free simulation software, schematic capture and waveform viewer with enhancements and models for improving the simulation of analog circuits.
To launch ready-to-run LTspice demonstration circuits for this part:
Step 1: Download and install LTspice on your computer.
Step 2: Click on the link in the section below to download a demonstration circuit.
Step 3: If LTspice does not automatically open after clicking the link below, 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.
Models for the following parts are available in LTspice:
LT3909
Product Recommendations
LT3909 Companion Parts
Recommended Related Parts
Design Resources
ADI has always placed the highest emphasis on delivering products that meet the maximum levels of quality and reliability. We achieve this by incorporating quality and reliability checks in every scope of product and process design, and in the manufacturing process as well. "Zero defects" for shipped products is always our goal.View our quality and reliability program and certifications for more information.
| Part Number | Material Declaration | Reliability Data | Pin/Package Drawing | CAD Symbols, Footprints & 3D Models |
|---|---|---|---|---|
| LT3909EDD#PBF | Material Declaration | Reliability Data | 12-Lead DFN (3mm x 3mm w/ EP) | |
| LT3909EDD#TRPBF | Material Declaration | Reliability Data | 12-Lead DFN (3mm x 3mm w/ EP) | |
| LT3909EMSE#PBF | Material Declaration | Reliability Data | 12-Lead MSOP w/ EP | |
| LT3909EMSE#TRPBF | Material Declaration | Reliability Data | 12-Lead MSOP w/ EP | |
| LT3909IDD#PBF | Material Declaration | Reliability Data | 12-Lead DFN (3mm x 3mm w/ EP) | |
| LT3909IDD#TRPBF | Material Declaration | Reliability Data | 12-Lead DFN (3mm x 3mm w/ EP) | |
| LT3909IMSE#PBF | Material Declaration | Reliability Data | 12-Lead MSOP w/ EP | |
| LT3909IMSE#TRPBF | Material Declaration | Reliability Data | 12-Lead MSOP w/ EP | |
| Wafer Fabrication Data | R580 Reliability Data |
PCN-PDN Information
Select a model from the dropdown below to subscribe to PCN/PDN notifications and view past notifications as well.
Support & Discussions
Sample & Buy
Ordering FAQs
See our Ordering FAQs for answers to questions about online orders, payment options and more.
Buy Now Pricing
(**) Displayed Buy Now Price and Price Range is based on small quantity orders.
List Pricing
(*)The 1Ku list pricing shown is for BUDGETARY USE ONLY, shown in United States dollars (FOB USA per unit for the stated volume), and is subject to change. International prices may differ due to local duties, taxes, fees and exchange rates. For volume-specific price or delivery quotes, please contact your local Analog Devices, Inc. authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.
Lead Times
Please see the latest communication from our CCO regarding lead times.
Sampling
A Sample link will be shown above, next to the part, only for parts that are included in our sample program. Selecting the Sample button will redirect to the third-party ADI Sample Site. The part selected will carry over to your cart on this site once logged in. Please create a new account there if you have never used the site before. Contact SampleSupport@analog.com with any questions regarding this Sample Site.
Evaluation Boards
Pricing displayed is based on 1-piece.
Up to two boards can be purchased through Analog.com. To order more than two, please purchase through one of our listed distributors.
Pricing displayed is based on 1-piece. The USA list pricing shown is for budgetary use only, shown in United States dollars (FOB USA per unit), and is subject to change. International prices may vary due to local duties, taxes, fees and exchange rates.