MIC2842AYMT-TR [Microchip]

The MIC2842A is a high efficiency White LED (WLED) driver designed to drive up to four LEDs and greatly extend battery life for portable display backlighting, and keypad backlighting in mobile devices. The MIC2842A architecture provides the highest possible efficiency by eliminating switching losses present in traditional charge pumps or inductive boost circuits. With a typical dropout of 40mV at 20mA, the MIC2842A allows the LEDs to be driven directly from the battery eliminating switching noise and losses present with the use of boost circuitry.

The MIC2842A features Dynamic Average Matching™ (DAM™) which is specifically designed to provide optimum matching across all WLEDs. The four 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 MIC2842A 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