10

LP5524

SNVS500C – JULY 2007 – REVISED NOVEMBER 2016

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8.2.2 Detailed Design Procedure

8.2.2.1 Recommended External Components

8.2.2.1.1

Input Capacitor, CIN

Although not required for normal operation, a capacitor can be added to VIN to reduce line noise. TI recommends

using a surface-mount multi-layer ceramic capacitor (MLCC). MLCCs with a X7R or X5R temperature

characteristic are preferred.

Table 2. List Of Recommended External Components

PARAMETER

VALUE

UNIT

TYPE

CIN

VDD bypass capacitor

100

nF

Ceramic, X7R or X5R

RISET

Current set resistor for 15.9-mA LED current

32.4

k

Ω

1%

LEDs

User defined

8.2.2.1.2

Current Set Resistor, RISET

If other than 5 mA current is required, RISET resistor can be used to adjust the current. For a 15.9-mA current a

32.4 k

Ω resistor is required. Accuracy of the resistor directly effects to the accuracy of the LED current. TI

recommends accuracy of 1% or better.

IDX = 515 / RISET (Amps)

(2)

Table 3. Recommended E96 Series (1% Tolerance) Current Set Resistors

RISET (kΩ)

IDX (mA)

RISET (kΩ)

IDX (mA)

169

3.0

34.0

15.1

127

4.1

32.4

15.9

102

5.0

30.1

17.1

84.5

6.1

28.7

17.9

73.2

7.0

26.7

19.3

64.9

7.9

25.5

20.2

56.2

9.2

24.3

21.2

51.1

10.1

23.2

22.2

46.4

11.1

22.1

23.3

42.2

12.2

21.5

24.0

39.2

13.1

20.5

25.1

36.5

14.1