AD9882 - Dual Interface For Flat Panel Displays

Laser Drivers 3.2Gbps SFP VCSEL w/Diagnostic Mtr

The LT3797 is a triple output DC/DC controller designed to drive three strings of LEDs. The fixed frequency, current mode architecture results in stable operation over a wide range of supply and output voltages. The LT3797 includes an integrated DC/DC converter to produce a regulated 7.5V supply for the N-channel MOSFET gate drivers of the three channels. This high efficiency converter enables the part to operate from a wide input voltage range from 2.5V to 40V. The LT3797 is designed so that each converter can use the most suitable configuration to drive its LED load, whether step-up, step-down or a combination. Two key features enable this flexibility: first the LT3797 can sense output current at the high side of the LED string; and second, the voltage feedback pin, FBH, is referred to the ISP current sensing input. The CTRL inputs provide output current analog dimming capability. The TG drivers level shift the PWM signals to drive the gates of external LED-disconnect P-channel MOSFETs, allowing high PWM dimming range, and providing LED overcurrent protection and short-circuit protected boost capability.Applications Automotive and Industrial Lighting RGB Lighting Billboards and Large Displays

The LT3952A is a current mode step-up DC/DC converter with an internal, 60V, 80m? DMOS power switch. The LT3952A is specifically designed to drive high power LEDs in multiple configurations. It combines input and output current regulation loops with output voltage regulation to operate as a flexible current/voltage source.Programmable switching frequency with optional spread-spectrum modulation provides EMI reduction, while still allowing optimization of the external components for efficiency or component size. The LED current is programmable with an external sense resistor, and can be adjusted from zero to full scale with a voltage at the CTRL pin. The external PWM input provides LED ON/OFF control and 4000:1 dimming ratio, and an internal PWM generator delivers the efficiency of PWM dimming to standalone or I/O limited applications. The LT3952A is available in the thermally enhanced 28-lead TSSOP package.Applications Display Backlighting Automotive and Avionic Lighting Accurate Current-Limited Voltage Regulators

Demonstration circuit DC2857A is a 36V 2A synchronous 2MHz boost LED driver featuring the LT3922-1. It drives a single string of LEDs at 330mA up to 34V when VIN is between 7V and 28V. It runs down to 4VIN with reduced ILED and can withstand VIN as high as 36V, but has overvoltage lockout (OVLO) set for 28V for this application. DC2857A runs at 2MHz switching frequency. Spread spectrum frequency modulation (SSFM) can be turned on with a simple jumper, reducing EMI. DC2857A comes with low EMI features including optimized layout, SSFM and input EMI filter. It passes CISPR 25 class 5 conducted and radiated EMI. It is protected against both open and short LED conditions and reports the faults. The LT3922-1 has an input voltage range from 2.8V to 36V. Its internal synchronous 2A 40V switches allow up to 34V of LEDs on the output with room for over voltage protection and overshoot during an open LED event. It has adjustable switching frequency between 200kHz and 2.5MHz. It can be synchronized to an external source or programmed with SSFM for low EMI. The PWMTG highside PWM MOSFET driver assists with short-circuit protection and versatility. LT3922-1 can be configured as a boost, boost-buck, or buck mode LED driver and maintain all of its low EMI, PWM dimming, and fault diagnostic features. The LT3922-1 can be PWM dimmed with an external PWM signal or an internally-generated PWM signal. DC2857A has a jumper that can be set to switch between internallygenerated PWM signal, externally-generated PWM signal, and no PWM signal (100% on). It can be analog dimmed with a control voltage on its control pin (CTRL). When run with both PWM dimming and spread spectrum, the spread spectrum aligns itself with the PWM signal for flicker-free operation. Small ceramic input and output capacitors are used to save space and cost. The board is designed with tiny, high frequency capacitors on both sides of the VOUT pins for a reduction in radiated EMI. The open LED overvoltage protection uses the IC’s constant voltage regulation loop to regulate the output to approximately 37.5V if the LED string is opened, although it may reach almost 40V peak during transient from running LEDs to open. There is a protection diode from LED+ to GND to prevent negative ringing during a short-circuit. The output current can be monitored through the ISMON output pin. Undervoltage and overvoltage lockout can be adjusted on the circuit with a few simple resistor choices. There is an EMI filter on the input of DC2857A. Please follow the recommend layout and four-layer thickness of DC2857A for low EMI applications. The LT3922-1 data sheet gives a complete description of the part, operation and applications information. The LT3922EUFD-1 is assembled in a 28-lead plastic 4mm × 5mm QFN package with a thermally enhanced ground pad. Proper board layout is essential for maximum thermal performance. See the data sheet section Layout Considerations.

The ADP8860SHIELD-EVALZ and the ADP8861SHIELD-EVALZ incorporate light emitting diodes (LEDs) for quick and easy evaluation of the ADP8860 and the ADP8861. Note that only the ADP8860SHIELD-EVALZ has dual light intensity sensors. The ADP8860SHIELD-EVALZ and the ADP8861SHIELD-EVALZ follow the form factor of a regular Arduino® shield to allow compatibility with microcontroller boards that use the same interface. These evaluation boards also incorporate a separate header dedicated to I2C communications. The ADP8860 and the ADP8861 are 7-channel LED drivers that utilizes a charge pump with selective gain for maximum efficiency. The LEDs driven by either device are programmable for maximum current and fade in and out times via the I2C interface. Only the ADP8860 has a programable light intensity threshold that can be set via the I2C interface of the device. Each channel can handle up to 30 mA (typical), except for the seventh channel, which can handle 60 mA (typical). Each channel can be unified to have the same fade in time and fade out time, or each channel can have an individual fade in time and fade out time for greater flexibility. For full details on the ADP8860 and the ADP8861, see the ADP8860 and the ADP8861 data sheets, which should be consulted in conjunction with the user guide when using these evaluation boards.

DC1039A-A: Demo Board for the LTC3207 600mA Universal Multi-Output LED/CAM Driver.

Demonstration circuit 1055 is a 250mA Universal Nine Channel Multimode (1x, 1.5x, 2x) Charge Pump LED Driver with two RGB displays and three white LEDs featuring the LTC3219. The LTC3219 is a low noise charge pump designed to drive nine universal LED current sources. The input voltage range is 2.9V to 5.5V. Each channel provides 28mA of LED current. The LTC3219 requires only five small ceramic capacitors to form a complete LED power supply and current controller. The maximum display currents are set with an internal precision current reference. On/Off blinking, gradation, and intensity are achieved via an I2C serial interface. There are 64 dimming states available for the universal LEDs. The DC590 controller board is required for proper operation.

Demonstration circuit DC2342A is a 60V synchronous boost LED controller featuring the LT®3762. It drives a single string of LEDs at 2A up to 32V when VIN is between 7V and 28V. It runs down to 4VIN with reduced ILED and can withstand VIN transients as high as 30V. DC2342A runs at approximately 300kHz switching frequency. Spread spectrum frequency modulation (SSFM) can be turned on with a simple jumper, reducing EMI. DC2342A is designed for high power step-up LED controller applications that require excellent efficiency across the VIN range. This demonstration circuit is protected against both open and short LED conditions, each having its own flag. The LT3762 has an input range from 2.5V to 42V. It has an adjustable switching frequency between 100kHz and 1MHz. Enabling SSFM spreads the switching frequency from fSW down to fSW – 30% for reduced EMI. SSFM speed is set by placing a capacitor from the SSFM pin of the LT3762 to ground, and can be disabled by shorting this pin to GND. DC2342A has a simple jumper option to enable/disable spread spectrum frequency modulation. The LT3762 can be PWM dimmed with an external PWM signal, as well as an internally generated PWM signal. A capacitor from PWM to GND of the LT3762 sets the PWM frequency, while the PWM duty cycle is determined by the voltage on the DIM terminal. Between 0V and 3V, VDIM gives between 0.4% and 97% PWM duty cycle. DC2342A has a jumper that can be set to switch between internally generated PWM signal, externally generated PWM signal, and no PWM signal (100% on). When run with both PWM dimming and spread spectrum enabled, the spread spectrum aligns itself with the PWM signal for flicker free operation. DC2342A can also be analog dimmed by placing a voltage source at either of its two CTRL turrets. Small ceramic input and output capacitors are used to save space and cost. The open LED overvoltage protection uses the IC’s constant voltage regulation loop to regulate the output to approximately 35.5V if the LED string is opened, although it may reach almost 40V peak during the transient caused by an open circuit. There is a protection diode from LED+ to GND to prevent negative ringing during a short-circuit. Undervoltage lockout can be adjusted on the circuit with a few simple resistor choices. Further modifications can be made to DC2342A to reconfigure the circuit from a boost topology to operate as a buck-mode or buck-boost mode LED driver. Please consult the factory for details. The LT3762 data sheet gives a complete description of the part, operation and applications information. The data sheet must be read in conjunction with this Demo Manual for demonstration circuit DC2342A. The LT3762EUFD is assembled in a 28-lead plastic 4mm × 5mm QFN package with a thermally enhanced ground pad. Proper board layout is essential for maximum thermal performance. See the data sheet section Layout Considerations.

Demo circuit DC1274A features the LTM8040 36V, 1A step-down constant current μModule® LED driver. The demonstration circuit is designed to drive a single LED or string of LEDs at up to 1A from a wide input voltage range of 4V to 36V. The maximum LED string voltage is 13V and the minimum voltage varies depending upon the BIAS pin supply arrangement.