Ver2.0

16

LD1018

16 Channel Constant Current Driver

PACKAGE POWER DISSIPATION( PD )

The LD1018 provides many package types such as 24-SOP package and 24-SSOP package. The

maximum allowable package power dissipation is determined as PD(max) = (Tj – Ta) / R_Theta_JA. When

16 output channels are turned on simultaneously, the actual power dissipation of package is PD(act) =

(IDD x VDD) + (IOUT x Duty x VOUT x 16). Therefore, to keep that PD(act) is less than PD(max).

The maximum allowable output current as a function of duty cycle is:

( R_Theta_JA = 85C/W )

IOUT = {[(Tj – Ta) / R_Theta_JA] – (IDD x VDD)} / VOUT / Duty / 16

where Tj = 150C

Package Power Dissipation

0

0.2

0.4

0.6

0.8

1

1.2

1.4

1.6

1.8

10 15 20 25 30 35 40 45 50 55 60 65 70 75 80 85 90

Ambient Temperature (C)

24SOP

24SSOP

Iout vs Duty (24-SSOP)

0

5

10

15

20

25

30

35

40

45

Duty

Ta = 85

Ta = 70

Ta = 55

Ta = 25

Iout vs Duty (24-SOP)

0

5

10

15

20

25

30

35

40

45

Duty

Ta = 85

Ta = 70

Ta = 55

Ta = 25

( R_Theta_JA = 75C/W )