12-Channels Pre-programmable Constant Current LED Driver

Version:A.006

Page 16

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DM621

Power Dissipation

The power dissipation of a semiconductor chip is limited to its package and ambient

temperature, in which the device requires the maximum output current calculated for given

operating conditions. The maximum allowable power consumption can be calculated by the

following equation:

Pd(max)(Watt) =

The relationship between power dissipation and operating temperature can refer to the figure

below:

0

0.5

1

1.5

2

2.5

3

3.5

4

0

20

40

60

80

100

120

140

160

Ambient Temperature Ta(℃)

Based on the Pd (max), the maximum allowable voltage of output terminal can be determined by

the following equation:

Tj(max)=150

°C

°C/Watt

°C/Watt

QFN20

TSSOP24