The LM3537 is a highly integrated LED driver capable of driving 8 LEDs in parallel for single display backlighting applications. Independent LED control allows for a subset of the main display LEDs to be selected for partial illumination applications.
I2C-compatible control allows full configurability of the backlighting function. The LM3537 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 a means to adjust the backlight intensity dynamically based upon the content of the display.
Four integrated LDOs are fully configurable through I2C capable of addressing point-of-load regulation needs for functions such as integrated camera modules. The LDOs can be powered from main battery source, or by a fixed output voltage of an external buck converter (post regulation) leading to higher conversion efficiency.
The LM3537 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.
LM3537 is offered in a tiny 30-bump DSBGA package.
Lighting:
8-channel Backlight Capability
Internal ALS Engine; PWM Input to Support CABC
Built-In Power Supply and Gain Control for Ambient Light Sensor
Up to 90% Efficiency
Adaptive Charge Pump with 1x and 1.5x Ggains for Maximum Efficiency
128 Dimming Steps for Group A, Exponential or Linear Dimming Selectable by Register Setup
8 Linear Dimming States for Group B
LDOs:
4 Programmable LDOs (300 mA/150 mA Output Currents)
Default Startup Voltage States
Low Dropout Voltage: 100 mV typ. at 150 mA Load Current
LDO Input Voltage = 1.8V to VIN_A
Overload Protection
Combined Common Features:
Wide Input Voltage Range: 2.7V to 5.5V
I2C-Compatible Serial Interface
2 General-Purpose Outputs
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