MIC2844AYMT-TR [Microchip]

The MIC2844A is a high efficiency linear White LED (WLED) driver designed to drive up to six WLEDs, greatly extending battery life for portable display backlighting keypad backlighting, and camera flash in mobile devices. The MIC2844A provides the highest possible efficiency as this architecture has no switching losses present in traditional charge pumps or inductive boost circuits. The MIC2844A provides six linear drivers which maintain constant current for up to six WLEDs. It features a typical dropout of 40mV at 20mA. This allows the WLEDs to be driven directly from the battery eliminating switching noise/losses present with the use of boost circuitry.

The MIC2844A features Dynamic Average Matching™ (DAM™) which is specifically designed to provide optimum matching across all WLEDs. The six channels are matched better than ±1.5% typical, ensuring uniform display illumination under all conditions. The LED brightness is preset by an external resistor and can be dimmed using a single-wire digital control. The digital interface takes commands from digital programming pulses to change the brightness in a logarithmic scale similar to the eye's perception of brightness. The single-wire digital brightness control is divided into two modes of operation; full brightness mode, or battery saving mode for a total of 49 brightness steps.

The MIC2844A operates over a junction temperature range of -40°C to +125°C.

• High efficiency (no voltage boost losses)
• Dynamic Average Matching™ (DAM™)
• Single wire digital control
• Input voltage range: 3.0V to 5.5V
• Dropout of 40mV at 20mA
• Matching better than ±1.5% (typical)
• Current accuracy better than ±1.5% (typical)
• Maintains proper regulation regardless of how many channels are utilized