10

1

2

3

4

8

7

6

5

Die1:

LED

Die2:

Detector

Figure 15. Diagram of ACPL-K43T for measurement

Thermal Resistance Model for ACPL-K43T

The diagram of ACPL-K43T for measurement is shown in Figure 15. Here, one die is heated first and the temperatures of

are recorded. With the known ambient temperature, the die junction temperature and power dissipation, the thermal

resistance can be calculated. The thermal resistance calculation can be cast in matrix form. This yields a 2 by 2 matrix for

our case of two heat sources.

X

=

Measurement data on a low K board:

Figure 16. Diagram of ACPL-K44T for measurement

Thermal Resistance Model for ACPL-K44T

The diagram of ACPL-K44T for measurement is shown in Figure 16. Here, one die is heated first and the temperatures of

all the dice are recorded after thermal equilibrium is reached. Then, the 2nd ,3rd and 4th die is heated and all the dice

temperatures are recorded. With the known ambient temperature, the die junction temperature and power dissipation,

the thermal resistance can be calculated. The thermal resistance calculation can be cast in matrix form. This yields a 4 by

4 matrix for our case of two heat sources.

X

=

1

2

3

4

8

7

6

5

Die1:

LED 1

Die2:

Detector 1

Die3:

LED 1

Die4:

Detector 2