1 Features
1• Drives three parallel high-voltage led strings for
display and keypad lighting
• High-voltage strings capable of up to 40-V output
voltage and up to 90% efficiency
• Up to 30 mA per current sink
• 11-Bit configurable dimming resolution
• PWM input for content adjustable brightness
control (CABC)
• Fully configurable LED grouping and control
• Integrated 1-A/40-V MOSFET
• Adaptive boost output to LED voltages
• Selectable 500-kHz and 1-MHz switching
frequency
• Four configurable overvoltage protection
thresholds (16 V, 24 V, 32 V, and 40 V)
• Overcurrent protection
• Thermal shutdown protection
• 29-mm2 Total solution size

2 Applications
• Power source for smart phone illumination
• Display, keypad, and indicator illumination

3 Description
The LM3697 11-bit LED driver provides highperformance
backlight dimming for 1, 2, or 3 series
LED strings while delivering up to 90% efficiency. The
boost converter with integrated 1-A, 40-V MOSFET
automatically adjusts to LED forward voltage to
minimize headroom voltage and effectively improve
LED efficiency.
The LM3697 is a high-efficiency three-string power
source for backlight or keypad LEDs in smart-phone
handsets. The high-voltage inductive boost converter
provides the power for three-series LED strings for
display backlight and keypad functions (HVLED1,
HVLED2, and HVLED3).
An additional feature is a pulse width modulation
(PWM) control input for content adjustable backlight
control, which can be used to control any highvoltage
current sink.
The LM3697 is fully configurable via an I2Ccompatible
interface. The device operates over a
2.7-V to 5.5-V input voltage range and a −40°C to
+85°C temperature range.