Analog Devices Inc./Maxim Integrated

The LTC3205 is a highly integrated multidisplay LED controller. The part contains a high efficiency, low noise fractional step-up/step-down charge pump to provide power for both main and sub white LED displays plus an RGB color LED display. The LTC3205 requires only four small ceramic capacitors plus two resistors to form a complete 3-display LED power supply and current controller.Maximum currents for the main/sub and RGB displays are set independently with a single resistor. Current for each LED is controlled with an internal current source. Dimming and ON/OFF control for all displays are achieved via a 3-wire serial interface. Four dimming states exist for the main and sub displays and 16 dimming states are available via internal PWM for the red, green and blue LEDs resulting in up to 4096 color combinations.The LTC3205 charge pump optimizes efficiency based on VINand LED forward voltage conditions. The part powers up in step-down mode and automatically switches to step-up mode once any enabled LED current source begins to enter dropout. Internal circuitry prevents inrush current and excess input noise during start-up and mode switching.The LTC3205 is available in a low profile 24-lead (4mm x 4mm x 0.8mm) QFN package.ApplicationsCellular PhonesWireless PDAsMultidisplay Handheld Devices

The LTC3207/LTC3207-1 are highly integrated multi-display LED drivers. The device contains a high-efficiency, low-noise charge pump to provide power to 12 universal LED current sources and one camera LED current source. The LTC3207/LTC3207-1 require only five small ceramic capacitors to form a complete LED power supply and current controller. In addition there are two I2C addresses available.The display currents are set by an internal precision current reference. Independent dimming, On/Off, blinking and gradation control for all universal current sources is achieved via the I2C serial interface. 6-bit linear DACs are available for adjusting brightness levels for each universal LED current source. The CAM current source has a 4-bit linear DAC to adjust brightness.The LTC3207/LTC3207-1 charge pumps optimize efficiency based on the voltage across the LED current sources. The device powers-up in 1x mode and will automatically switch to boost mode whenever any enabled LED current source begins to enter dropout. The first dropout switches the IC into 1.5x mode and a subsequent dropout switches the LTC3207/LTC3207-1 into 2x mode. The device resets to 1x mode whenever a data register is updated via theI2C port.ApplicationsVideo Phones with QVGA+ Displays

The LTC3208 is a highly integrated multidisplay LED controller. The part contains a 1A high effi ciency, low noise charge pump to provide power to the MAIN, SUB, RGB, CAM and AUX LED displays. The LTC3208 requires only 4 small ceramic capacitors and one current set resistor to form a complete LED power supply and current controller.The maximum display currents are set by a single external resistor. Current for each LED is controlled by a precision internal current source. Dimming and On/Off for all displays is achieved via the I2C serial interface. 256 brightness levels are available for the MAIN and SUB displays. 16 levels are available for the RGB and CAM displays. Four AUX current sources can be independently assigned via the I2C port to the CAM, SUB, MAIN or AUX DAC controlled displays.The LTC3208 charge pump optimizes effi ciency based on the voltage across the LED current sources. The part powers up in 1x mode and will automatically switch to boost mode whenever any enabled LED current source begins to enter dropout. The fi rst dropout switches the part into 1.5x mode and a subsequent dropout switches the LTC3208 into 2x mode. The part is available in a small 5mm × 5mm 32-lead QFN package.ApplicationsVideo/Camera Phones with QVGA + Displays

The LTC3210 is a low noise charge pump DC/DC converter designed to drive four MAIN LEDs and one high current CAM LED for camera lighting. The LTC3210 requires only four small ceramic capacitors and two current set resistors to form a complete LED power supply and current controller.Built-in soft-start circuitry prevents excessive inrush current during start-up and mode changes. High switching frequency enables the use of small external capacitors. Independent MAIN and CAM full-scale current settings are programmed by two external resistors. Shutdown mode and current output levels are selected via two logic inputs.The full-scale current through the LEDs is programmed via external resistors. ENM and ENC are toggled to adjust the LED currents via internal counters and DACs. The part is shut down when both ENM and ENC are low for 150μs (typ).The charge pump optimizes efficiency based on the voltage across the LED current sources. The part powers up in 1x mode and will automatically switch to boost mode whenever any enabled LED current source begins to enter dropout. The LTC3210 is available in a 3mm × 3mm 16-lead QFN package.ApplicationsMulti-LED Light Supply for Cellphones/DSCs/PDAs

The LTC3210-2/LTC3210-3 are low noise charge pump DC/DC converters designed to drive three or four MAIN LEDs and one high current CAM LED for camera lighting. The LTC3210-2/LTC3210-3 require only four small ceramic capacitors and two current set resistors to form a complete LED power supply and current controller.Built-in soft-start circuitry prevents excessive inrush current during start-up and mode changes. High switching frequency enables the use of small external capacitors. Independent MAIN and CAM full-scale current settings are programmed by two external resistors.Shutdown mode and current output levels are selected via two logic inputs. ENM and ENC are toggled to adjust the LED currents via internal counters and DACs. A 5-bit linear DAC (32 steps) provides high resolution brightness control for the MAIN display.The charge pump optimizes efficiency based on the voltage across the LED current sources. The part powers up in 1x mode and will automatically switch to boost mode whenever any enabled LED current source begins to enter dropout. The LTC3210-2/LTC3210-3 are available in a 3mm × 3mm 16-lead QFN package.ApplicationsMulti-LED Light Supply for Cellphones/DSCs/PDAs

The LTC3212 is a low noise charge pump RGB LED driver capable of driving three LEDs up to 25mA each from a 2.7V to 5.5V input. Low external part count (one flying capacitor, two bypass capacitors and one to three programming resistors) makes the LTC3212 ideally suited for small, battery-powered applications.Built-in soft-start circuitry prevents excessive inrush current during start-up and mode switching. High switching frequency enables the use of small external capacitors. The charge pump shuts down to a high impedance mode to prevent LED leakage while the LTC3212 is off.Each LED may be individually turned on or off via a single pin interface. The current through the LEDs may be individually programmed with resistors or may share a single programming resistor. White mode adjusts the red, green and blue LED current ratios for a white light when all three LEDs are programmed to be on.LED currents are regulated using internal low dropout current sources. Automatic mode switching optimizes effi ciency by monitoring the LED current drivers and switches mode only when dropout is detected. The part is available in a 3mm × 2mm 12-lead DFN package.ApplicationsCellular PhonesMedia PlayersRGB Back Lights