The LM3535 is a highly integrated LED driver capable of driving 8 LEDs in parallel for large display applications. Independent LED control allows for a subset of the 6 main display LEDs to be selected for partial illumination applications. In addition to the main bank of 6, the LM3535 is capable of driving an additional 2 independently controlled LEDs to support Indicator applications.

The LED driver current sinks are split into three independently controlled groups. The primary group can be configured to drive up to six LEDs for use in the main phone display. Groups B and C are provided for driving secondary displays, keypads and indicator LEDs. All of the LED current sources can be independently turned on and off providing flexibility to address different application requirements.

The LM3535 provides multi-zone Ambient Light Sensing (1 or 2 ALS inputs depending on option) allowing autonomous backlight intensity control in the event of changing ambient light conditions. A PWM input is also provided to give the user a means to adjust the backlight intensity dynamically based upon the content of the display.

The LM3535 provides excellent efficiency without the use of an inductor by operating the charge pump in a gain of 3/2 or in Pass-Mode. The proper gain for maintaining current regulation is chosen, based on LED forward voltage, so that efficiency is maximized over the input voltage range.

The LM3535 is available in a tiny 20-bump, 0.4mm pitch, thin DSBGA package.

• Drives Up to 8 LEDs With Up to 25mA of Diode Current Each
• External PWM Input For Dynamic Backlight Control
• Multi-Zone Ambient Light Sensing (ALS)
• Dual-ALS Sensor Inputs (LM3535-2ALS Only)
• ALS Interrupt Reporting
• Independent On/Off Control for All Current Sinks
• 128 Exponential Dimming Steps with 600:1 Dimming Ratio for Group A (Up to 6 LEDs)
• 8 Linear Dimming States for Groups B (Up to 3 LEDs) and D1C (1 LED)
• Programmable Auto-Dimming Function
• Up to 90% Efficiency
• 0.55% Accurate Current Matching
• Internal Soft-Start Limits Inrush Current
• True Shutdown Isolation for LEDs
• Wide Input Voltage Range (2.7V to 5.5V)
• Active High Hardware Enable
• Total Solution Size < 16mm2
• Low Profile 20 Bump DSBGA Package (1.650mm × 2.055mm × 0.6mm)