Dear Specialists,
My customer has similar question about UA78L05.
I would be grateful if you could advise in more detail.
---
1. Overcurrent protection circuit specifications
How much current does the overcurrent protection circuit start operating?
Is there any data that can be confirmed?
2. Junction temperature during protection operation
In the short circuit test, the voltage between input and output was about 14V when 120mA was flowing through the IC.
When the IC loss is calculated from that, it becomes 120mA * 14V ≒ 1.7W.
Also, when checking the IC data sheet, it was ΘJC: 88.1 ° C / W. (PK package product)
The temperature rise is 1.7W * 88.1 ℃ / W ≒ 150 ℃, and the junction temperature exceeds the part rating of 150 ℃ in consideration of the case temperature of the parts.
Calculations result in the junction temperature exceeding the rating when the protective operation is in effect.
Is this conclusion correct?
ｰｰｰ
I appreciate your great help in advance.
Best regards,
Shinichi
