Datasheet

Interfacing with the GPIO Bus

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5 Interfacing with the GPIO Bus

The PWM control pins GCTRL, BCTRL, and RCTRL are internally pulled low, push-pull I/O ports are

recommended to interface properly with the system MCU. The device enable, EN pin is internally pulled

high, so an open drain I/O port is recommended.

6 Changing the Preset LED Current

The factory preset LED current of the LM3435 evaluation board is 1.5A, In case the user need to make a

change of the preset LED current, it can be done by simply replacing the LED current setting resistors R1,

R2 and R3. The I

LED(MIN)

condition should not be violated for proper regulation, that is, the I

LED

current for all

operation conditions must be no less than 600mA with this evaluation board. Some popular values for

user's reference are listed in below. For details about the operation and calculations of the components,

please see LM3435 Compact Sequential Mode RGB LED Driver with I2C Control Interface (SNVS724).

Preset LED Current, I

LED

R1, R2, R3 Value

1.5A 16.5kΩ

1.0A 24.75kΩ

0.75A 33.0kΩ

AN-2196 LM3435 Evaluation Board SNVA506A–October 2011–Revised May 2013

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