ACPL-344JT Datasheet, PDF (13/17 Pages) AVAGO TECHNOLOGIES LIMITED – Miller-Current Clamping

Thermal Characteristics are based on the ground planes layout of the evaluation PCB, shown as follows:
60 mm
60 mm
VEE1
VEE1
VEE2
VEE2
PCB Top Side
PCB Bottom Side
Notes on Thermal Calculation
Application and environmental design for ACPL-344JT must ensure that the junction temperature of the internal ICs and
LED within the gate driver optocoupler do not exceed 150°C. The following equations calculate the maximum power
dissipation and its corresponding effect on junction temperatures.
LED Junction Temperature = (A_EA × P_E) + (A_EI × P_I) + (A_EO × P_O) + T_A
Input IC Junction Temperature = (A_EI × P_E) + (A_IA × P_I) + (A_IO × P_O) + T_A
Output IC Junction Temperature = (A_EO × P_E) + (A_IO × P_I) + (A_OA × P_O) + T_A
P_E—LED Power Dissipation
P_I—Input IC Power Dissipation
P_O—Output IC Power Dissipation
Calculation of LED Power Dissipation
LED Power Dissipation, P_E = I_F(LED) (Recommended Max) × V_F(LED) (125°C) × Duty Cycle
Example: P_E = 16 mA × 1.25 × 50% duty cycle = 10 mW
Calculation of Input IC Power Dissipation
Input IC Power Dissipation, P_I = I_{CC1 (Max)} × V_CC1 (Recommended Max.)
Example: P_I = 6 mA × 18 V = 108 mW
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