1 Features
1• Drives Up to 8 LEDs Each With Up to 25 mA of
Diode Current
• External PWM Input for Dynamic Backlight Control
• Multi-Zone Ambient Light Sensing (ALS)
• 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
• Wide Input Voltage Range (2.7 V to 5.5 V)
• Active High Hardware Enable
• Total Solution Size < 16 mm2
• Low Profile 20-Pin DSBGA Package

2 Applications
• Smart-Phone LED Backlighting
• Large Format LCD Backlighting
• General LED Lighting

3 Description
The LM3535 device is a highly integrated LED driver
capable of driving 8 LEDs in parallel for large display
applications. Independent LED control allows
selection of a subset of the 6 main display LEDs 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 allowing autonomous backlight intensity
control in the event of changing ambient light
conditions. A PWM input is also provided to give the
user the 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-pin, 0.4-mm
pitch, thin DSBGA package.