Demonstration circuit 2176A features the LT3909, a 2-string × 50mA, 2MHz step-up LED driver with ±1.8% current matching. The LT3909 precisely regulates two LED strings for equal current, supports LED dimming that reduces brightness down to a 1/40,000 ratio, protects against faults and also reports faults. The LT3909 consists of a step-up converter with a fixed 2MHz switching frequency and current sources for the LED strings. The maximum current in each LED string is 40mA. The ISET resistor can be changed to 20.0kΩ to program the string current to 50mA – see the data sheet for an application example with 50mA string current. Voltage feedback resistors optimize operation for LEDs that are 35V maximum.

The LTM8005 is a 38VIN, 38VOUT boost ?Module (powermicromodule) LED driver designed to regulate current orvoltage and is ideal for driving LEDs. The fixed frequencyand current mode architecture result in stable operationover a wide range of supply and output voltages. Spreadspectrum frequency modulation (SSFM) can be activatedfor improved electromagnetic compatibility (EMC) performance.The ground-referred voltage FB pin serves as theinput for several LED protection features, and also allows theconverter to operate as a constant voltage source. The PWMinput provides LED dimming ratios of up to 3000:1, and theCTRL inputs provide additional analog dimming capability.The low profile package enables utilization of unusedspace on the bottom of PC boards. The LTM8005 is packagedin thermally enhanced, compact over-molded BallGrid Array (BGA) package suitable for automated assemblyby standard surface mount equipment. The LTM8005is RoHS compliant.APPLICATIONS High Power LED, High Voltage LED Accurate Current-Limited Voltage Regulators

The LT3492 is a triple output DC/DC converter designed to operate as a constant-current source and is ideal for driving LEDs. The LT3492 works in buck, boost or buck-boost mode. The LT3492 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 external PWM input provides 3000:1 LED dimming on each channel. 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 LT3492 is programmed with an external sense resistor. The CTRL pin is used to adjust the LED current either for analog dimming or over-temperature protection.Applications RGB Lighting Billboards and Large Displays Automotive and Avionic Lighting Constant-Current Sources

Demonstration circuit DC1666A is a synchronous four-switch buck-boost LED driver controller. It accepts an input voltage from 4.7V to 60V, and drives up to 25V of LEDs at 2A. DC1666A features both PWM and analog dimming of the LED string. It has an OPENLED flag that indicates when the LED string has been removed and it has a SHORTLED flag that indicates that the output has been shorted to GND. In both cases, the IC remains in control and well protected.

The ADD5211 is a four-string, white LED driver for backlight applications based on high efficiency, current mode, step-up converter technology. The boost controller drives an external MOSFET switch for step-up regulation from an input voltage of 4.5 V to 40 V and a pin adjustable operating frequency from 200 kHz to 1.2 MHz. An adjustable UVLO function is implemented to reduce input current during power-off.The ADD5211 provides four regulated current sinks for uniform brightness intensity. Each current sink can be driven from 40 mA to 200 mA; the LED driving current is pin adjustable using an external resistor. With an input PWM interface, the ADD5211 drives up to four parallel strings of multiple series connected LEDs.Additional features include LED short protection, LED open protection, boost output short protection, overvoltage protection, cycle-by-cycle current limit, and thermal shutdown for both the IC and the LED array. An open-drain fault output is also included. A programmable soft start is implemented to reduce inrush current during startup. Applications LCD monitor and TV LED backlights Industrial lighting

Laser Drivers Integrated Circuits (ICs)

LIGHTING DEVELOPMENT KITS;

LED Lighting Development Tools LT3791 4.7V-60V input to drive 25V of LEDs at 2A (scaleable to 100W)

The LT3003 drives three separate strings of LEDs up to 350mA/channel with 3% accurate current matching, resulting in uniform LED brightness and intensity. This approach is superior to conventional methods of running three separate channels with external ballast resistors requiring expensive factory calibration.The LT3003 operates in boost, buck and buck-boost mode. A True Color PWM Dimming ratio of up to 3000:1 is achievable using a logic-level signal at the PWM pin for all modes without the need for external level-shifting circuitry. For applications with input supply above and below the output voltage of the LED strings, the LT3003 allows the LEDs to be returned to the input supply (buck-boost mode) instead of being limited to only SEPIC solutions.The LT3003 is ideal for high power LED driver applications such as TFT LCD backlighting and heads-up displays. Additional overtemperature outputs allow appropriate system management for increased reliability.The LT3003 is available in a small 10-pin MSE package.Applications High Power LED Ballaster Automotive Lighting Video Cameras TFT LCD Backlighting

The ADN2871 laser diode driver (LDD) is designed for advanced SFP and SFF modules, using SFF-8472 digital diagnostics. The ADN2871 supports operation from 50 Mbps up to 4.25 Gbps.Average power and extinction ratios can be set with a voltage provided by a microcontroller DAC or by a trimmable resistor or digital potentiometer. The average power control loop is implemented using feedback from a monitor photodiode. The device provides bias and modulation current monitoring, as well as fail alarms and automatic laser shutdown (ALS). The device interfaces easily with the Analog Devices, Inc., ADuC7019 and ADuC7020 family of MicroConverter® devices and with the ADN2890, ADN2891, and ADN2892 family of limiting amplifiers to make a complete SFP/SFF transceiver solution. An SFP reference design isavailable.The product is pin-compatible with the ADN2870 dual-loop LDD, allowing the same design to work with either device. For dual-loop control applications, refer to the ADN2870 data sheet. The product is available in a space-saving 4 mm × 4 mm LFCSP specified over the −40°C to +85°C temperature range.Applications 1×/2×/4× Fibre Channel SFP/SFF modules Multirate OC3 to OC48-FEC SFP/SFF modules LX-4 modules DWDM/CWDM SFP modules 1GE SFP/SFF transceiver modules VCSEL, DFB, and FP transmitters