LM3509SDX

• Integrated OLED display power supply and LED driver
• 30 mA capable of driving up to 10 LEDs
• When driving 5 LEDs at 20mA, it can deliver up to 40 mA to 21V
• More than 90% efficiency
• 32 exponential dimming steps
• 0.15% accurate current matching between strings
• Internal soft-start limits inrush current
• True off-isolation of LEDs
• Input voltage range of 2.7V to 5.5V
• 21V overvoltage protection
• 1.27MHz fixed frequency operation
• Low Profile 10-Pin LLP Package (3 × 3 ×0.8mm)
• Universal I/O
• Active low hardware reset

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The LM3509 current mode boost converter provides two separate outputs. The first output (master) is a constant sink current to drive the series white LED. The second output (SUB/FB) is a configurable series of white LEDs biased as a constant sink or constant output voltage feedback pin set to power the OLED panel.

When configured with a dual-output white LED bias supply, the LM3509 adaptively adjusts the supply voltage of the LED string to maximize efficiency and ensure current sink regulation is maintained. The maximum current for each output is through an external low-power resistor. One me 2 The C-compatible interface allows independent LED current adjustment, both step current output from 0 to a maximum of 32 exponents. When configured as a white LED + OLED bias supply, the LM3509 can independently drive a string of 5 white LEDs and OLED panels to provide a constant output voltage to 21V.

The output overvoltage protection function is turned off if the above allows the use of small low voltage outputs_capacitorThe 21V, V OUT rises. The LM3509 is available in a small 10-pin thermally enhanced LLP package that operates over the -40°C to +85°C temperature range.

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• Backlight in dual-display portable applications
• Large format LCD backlight
• OLED panel power supply