| ??? 01/10/09 14:01 Read: times |
#161406 - Agreed Responding to: ???'s previous message |
Per Westermark said:
Thanks , Actually I meant 1.2+20*0.12W =1.4W that it will begin to dissipate at that elevated temp unless any action is taken. What 1.4W that it will begin to dissipate??? The datasheet does not say how much it will dissipate at a specific temperature. The datasheet does say how much it is allowed to dissipate at a specific temperature. And when the temperature rises above 65C, the allowed dissipation will decrease, not increase. At 85C, the dissipation will not increase to 1.4W. Instead, you must make sure that the maximum dissipation is no more than 0.96W, since you have 20C less margin between ambient temperature and max allowed die temperature. Edit: Compare to a PC processor. Most new processors have temperature protection. When they get too hot, they have to reduce the working speed to reduce the dissipated power and compensate for a too high ambient temperature. If they did not, then the die would get overheated if the fan fails or the heatsink isn't correctly mounted. If there isn't a clocking speed to reduce, then the dissipation must be reduced by decreasing the supply voltage or bus load. I got a bit confused . -Ap |
| Topic | Author | Date |
| Thermal stress reduction for IC | 01/01/70 00:00 | |
| Ask the manufacturer! | 01/01/70 00:00 | |
| Wear from temperature cycling | 01/01/70 00:00 | |
| loose vs lose | 01/01/70 00:00 | |
| What's the rated MTBF? | 01/01/70 00:00 | |
| The temperature may rise | 01/01/70 00:00 | |
| automotive grade is 125C | 01/01/70 00:00 | |
| You should have mentioned 150C | 01/01/70 00:00 | |
| Why does it rise? | 01/01/70 00:00 | |
| Though its able | 01/01/70 00:00 | |
| Sounds unlikely to me | 01/01/70 00:00 | |
| You need to consume power to be able to save power | 01/01/70 00:00 | |
| Why not having some numbers? | 01/01/70 00:00 | |
| Power dissipation | 01/01/70 00:00 | |
| Not 1.4W at 85C but 1.2-0.24 = 0.96W | 01/01/70 00:00 | |
| figure 1.4W | 01/01/70 00:00 | |
| Reversed logic | 01/01/70 00:00 | |
| Agreed | 01/01/70 00:00 | |
| Answers | 01/01/70 00:00 | |
| The webpage accepts | 01/01/70 00:00 | |
| Useful links... | 01/01/70 00:00 | |
| Tjmax | 01/01/70 00:00 | |
| Please read the datasheet again, carefully! | 01/01/70 00:00 | |
Not Obsession only info | 01/01/70 00:00 |