Features and Benefits
- True Color PWM™ Dimming Delivers Up to 3000:1 Dimming Ratio
- Built-In Gate Driver for PMOS LED Disconnect
- Three Independent Driver Channels with 750mA, 45V Internal Switches
- Operates in Buck, Boost, Buck-Boost Modes
- CTRL Pin Accurately Sets LED Current Sense Threshold Over a Range of 10mV to 100mV
- Adjustable Frequency: 330kHz to 2.1MHz
- Open LED Protection
- Wide VIN Supply Range:
- Operation from 3V to 30V
- Transient Protection to 40V
- Surface Mount Components
- 28-Lead (4mm × 5mm) QFN and TSSOP Packages
The LT3496 is a triple output DC/DC converter designed to operate as a constant-current source and is ideal for driving LEDs. The LT3496 works in buck, boost or buck-boost mode. The LT3496 uses a fixed frequency, current mode architecture resulting in stable operation over a wide range of supply and output voltages. A frequency adjust pin allows the user to program switching frequency between 330kHz and 2.1MHz to optimize efficiency and external component size.
The LT3496 supports 3000:1 dimming control on each channel. Each of the three regulators is independently operated by that channel’s PWM signal. The PWM feature allows precise adjustment of the color mixing or dimming ratio of the LED source. Each of the three channels has a built-in gate driver to drive an external LED-disconnect P-channel MOSFET, allowing high dimming range. The output current range of each channel of the LT3496 is programmed with an external sense resistor.
The CTRL pins are used to adjust the LED currents either for analog dimming or overtemperature protection.
- RGB Lighting
- Billboards and Large Displays
- Automotive and Avionic Lighting
- Constant-Current Sources
Product Lifecycle Production
At least one model within this product family is in production and available for purchase. The product is appropriate for new designs but newer alternatives may exist.
Evaluation Kits (2)
Demonstration circuit 986 is a Triple Step-Down LED Driver featuring the LT3496EUFD. The LT3496 is a triple output DC/DC converter designed to operate as current sources for driving high current LEDs. Each ofthe three regulators on the demo board is independently operated. The default current for each output channel is 500mA. The output current should not exceed the rated current of the LEDs used. The maximum voltage of an LED string the demo board can drive is limited by the duty cycle and the input voltage of the LT3496.
The maximum power input voltage (PVIN ) is 45V. As a result, each channel of the demo board can drive up to ~31V total LED voltage. The LT3496's input voltage range is 3V to 30V (with 40V transients), however to minimize power dissipation the demo board uses a 3V to 5.5V supply.
Demonstration circuit 1288 is a Triple Boost or Buck-Boost LED Driver featuring the LT3496EUFD (for evaluating an LT3496 buck mode LED driver, use the demonstration circuit 986). The LT3496 is a triple output DC/DC converter designed to operate as current sources for driving high current LEDs. The board can be configured as either a buck-boost (default) or boost solution. The current for each output is set at 200mA in either mode. The three LEDs are included in the demo board assembly.
The operating power input voltage (PVIN) range is 8V to 16V. The buck-boost circuit can tolerate an input voltage up to 40V when the LED string is on the high side. The part shuts down when the overvoltage threshold is reached. For a typical application with 5 LEDs totaling 16V of LED voltage, the circuit will operate until PVIN reaches 22V if the overvoltage protection is set to 38V.
Tools & Simulations
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:
Technical Articles (2)
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.
Sample & Buy
The USA 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. sales office or authorized distributor. Pricing displayed for Evaluation Boards and Kits is based on 1-piece pricing.