LP5012 datasheet(36/52 Pages) TI2

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9.2.1 Design Requirements

Set the LED current to 15 mA using the RIREF resistor. Select the proper value for the other external

components, like VCAP pin capacitor and the SCL/SDA pullup resisters.

9.2.2 Detailed Design Procedure

LP50xx scales up the reference current (IREF) set by the external resistor (RIREF) to sink the output current (IOUT)

at each output port. The following formula can be used to calculate the external resistor (RIREF):

IREF =KIREF ×

IREF

SET

(2)

The SCL and SDA lines must each have a pullup resistor placed somewhere on the line (the pullup resistors are

normally located on the bus master). In typical applications, values of 1.8 kΩ to 4.7 kΩ are used.

VCAP is internal LDO output pin. This pin must be connected through a 1-µF capacitor to GND. Place the

capacitor as close to the device as possible.

TI recommends having a 1-µF capacitor between VCC and GND to ensure proper operation. Place the capacitor

as close to the device as possible.

9.2.3 Application Curves

The test condition for Figure 9-2 is that the testing under bank control, with the register’s (0x04, 0x05, 0x06)

value is 0xF0.

The test condition for Figure 9-3 is that the testing under bank control, with the register’s (0x04, 0x05, 0x06)

value is 0x0F.

Figure 9-2. Current Waveform of OUT0, OUT1,

OUT2 and OUT3

Figure 9-3. Current Waveform of OUT0, OUT1,

OUT2 and OUT3

LP5009, LP5012

SLVSEH2B – MAY 2019 – REVISED AUGUST 2020

www.ti.com

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LP5012 데이터시트(PDF) 36 Page - Texas Instruments