Features and Benefits
- Eight Independent 17V 330mΩ NMOS Switches
- Independent On/Off/Dimming Control of 1 to 4 LEDs for Each Switch
- I2C Multidrop Serial Interface with Programmable Open LED and Shorted LED Fault Reporting
- 16 Unique I2C Addresses
- VDD Range: 2.7V to 5.5V and VIN Range: 8V to 60V
- Digital Programmable 256:1 PWM Dimming
- Fade Transition Between PWM Dimming States
- Optional Internal Clock Generator or External Clock Source for PWM Dimming
- Open LED Overvoltage Protection
- Flicker Free PWM Dimming
- AEC-Q100 Qualified for Automotive Applications
The LT3965/LT3965-1 is an LED bypass switching device for dimming individual LEDs in a string using a common current source. It features eight individually controlled floating source 17V/330mΩ NMOS switches. The eight switches can be connected in parallel and/or in series to bypass current around one or more LEDs in a string. The LT3965 is initialized with all switches off (LEDs on), and the LT3965-1 is initialized with all switches on (LEDs off)The LT3965/LT3965-1 uses the I2C serial interface to communicate with the microcontroller. Each of the eight channels can be independently programmed to bypass the LED string in constant on or off, or PWM dimming with or without fade transition. Using the fade option provides 11-bit resolution logarithmic transition between PWM dimming states. The LT3965/LT3965-1 provides an internal clock generator and also supports external clock source for PWM dimming. The LT3965/LT3965-1 reports fault conditions for each channel such as open LED and shorted LED. The four address select pins allow 16 LT3965/LT3965-1 devices to share the I2C bus. The device is available in a 28-lead TSSOP package.
- Automotive LED Headlight Clusters
- Large LED Displays
- Automated Camera Flash Equipment
- RGBW Color Mixing Lighting
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 (1)
Demonstration circuit DC2218A is a matrix LED dimmer system featuring the LT3965 8-switch matrix LED dimmer IC. There are 16 500mA LEDs that can be individually turned on, off, or PWM dimmed with two 8-switch LED dimmer LT3965 ICs. The two strings of LEDs are driven with two buck LED driver outputs of the LT3797 triple LED controller IC. The third channel of the LT3797 serves as a 30V pre-boost voltage regulator to provide a proper input voltage to the two buck LED driver channels. DC2218A can be driven from a 9V to 30V input and can survive transients up to 36V.
Documentation & Resources
DC2218A - Demo Manual12/16/2015
Matrix LED Dimmer2/10/2016
Tools & Simulations
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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.