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HELP! the temperature problem of DM6446

simayizhi
Intellectual 295 points
Other Parts Discussed in Thread: TPS54312

TI engineers,

 

I have the trouble about the temperature of DM6446. When I tested my own board of 6446, I found the chip temperature on the high side after one or two minute. BUt the program can be loaded in DM6446 to run under this case.

 

After I found the abnormal phenomenon, I tested the power of my board, and the power had a lot of niose(5V、3.3V、1.8Vand 1.2V). But, when I cut off 1.2V(the output of TPS54312), the power of 5V、3.3V and 1.8V hadn't niose. The niose appeared again when added 1.2V.

 

Beacause the resistance of DM6446 is about 200 ohm, then I used 200 ohm as the load of TP54312, and 1.2V is normal, no niose.

 

I tested the static state resistance of the port of 1.2V and GND of DM6446, and the value is less than 200 ohm, and only about 100 ohm. 

 

I think the niose caused the chip of DM6446 heated abnormally, but what caused the power niose? Some people think it caused by welding quality of BGA, they doubted the welding lead to fever. And I think since the chip 6446 can work under the program, the welding of chip ought to be good.

 

I don't konw how to solve these problems, and the abnormal phenomenon affected my work on DM6446 seriously.

I need your help. Thank you!

 

min

  • 0
    TI__Expert 5475 points

    Hi,

    Not sure as to what you mean by the processor has a resistance of 200ohm and you replaced the processor with a resistor. This is a wrong approach and of-course you will not be seeing noise when you are powering up a singler resistor.

    As far as noise is concerned some degree of noise is acceptable and is expected. You need to measure the peak-to-peak noise to understand what is acceptable or not.

    What probably makes sense to do is for you to measure the current from each supply and identify the supply that is drawing more current than it should. Hopefully from there, you can identify a possilble of short or some other error that causes the extra curent draw.

    Best regards, Zegeye

  • 0 in reply to Zegeye Alemu
    Intellectual 295 points

     

    Zegeye,

     

    Thanks for your reply!

     

    I replaced the processor with the 200ohm resistor, as I wanted to make sure the TP54312 can work well (don't appear the niose) with the load. 

     

    I have to admit that the niose appeared on my 6446 board is not acceptable, because the peak I measured is up to 2.0V, and the narmal level is 1.2V.  The picture I stick is the test picture of 1.2V, I think these niose cannot make chip work well.

    Here, I need to explain that this board is my second board, and this is as same as the first one. But the first board don't appear the niose things. 

     

     

    Previously, some engineer suspect the issue is caused by the BGA welding. How about the possibility?

     

     

    min