4-channel LED drivers from AnalogicTech

31st October 2008

Advanced Analogic Technologies Inc., Europe

ES Admin

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Datasheet

AnalogicTech has introduced the AAT3104 and AAT3195, two 4-channel, charge pump-based LED drivers for larger LCD screens in reduced feature set cell phones and portable systems. Available in compact 2 x 2.1mm packages, the devices offer designers 16-step, 32-step or PWM current control in a space-saving footprint. By using an efficient charge pump with 1x and 2x modes, the AAT3104 and AAT3195 drivers reduce the external component count by 25% over competing solutions.

To deliver uniform brightness and excellent matching between adjacent LEDs, the AAT3104 provides common current sinks for command anode configurations, while the AAT3195 supports common sources for common cathode configurations.

As engineers add new functionality to entry-level cell phones and other portable systems, they often integrate larger displays into their designs. By providing the required compliance voltage to forward bias the LED as well as a means to control and set the desired current for both common anode and common cathode configurations with four LEDs, these additions to AnalogicTech’s extensive LED driver product portfolio offer portable system designers improved design flexibility, high power efficiency, lower component count, and multiple current control options in a space-saving package.
The AAT3104 is a current-source LED driver capable of driving up to four LEDs at up to 30mA each. The charge pump-based device automatically switches between a 1x and 2x mode to maximize efficiency and optimize LED current accuracy and matching. LED output current accuracy is +/-10%. LED output current matching is +/-3%.

The device operates at a 1MHz switching frequency and comes in two versions that offer either 16-step (AAT3104-1) or 32-step (AAT3104-2) control of LED brightness via AnalogicTech’s patented single-wire S2Cwire interface. A PWM version, the AAT3105, will be available shortly.

For LEDs using common cathode configurations, the AAT3195 offers a charge pump-based current-source LED driver for similar 4-channel applications. Like the AAT3104, the AAT3195 drives up to four LEDs at up to 30mA each. The AAT3195 also automatically switches between 1x and 2x mode to maintain excellent efficiency, current matching and accuracy. The AAT3195 operates at a 1MHz switching frequency and comes in three versions with different interfaces. The AAT3195-1 delivers 30mA current across 32-steps using the S2Cwire interface. The AAT3195-2 supports 20mA current across 32 steps also using the S2Cwire interface. And the AAT3195-3 features a PWM interface.

Both drivers feature automatic soft-start, a low-current shutdown mode to conserve power, and integrated thermal protection.

The AAT3104 and AAT3195 are qualified across the -40 to +85 degrees C temperature range. Both drivers are available in 2 x 2.1mm, 10-lead SC70JW packages.