I'm struggling to get a second batch of my custom boards working. The first batch of three used TMS320DM6467ZUT1 chips, with appropriate crystal speed (27MHz) and core power supply voltage (1.2V). When just powered on and not yet programmed, they each drew something like 20mA or less with a 12V supply, including any supply inefficiencies.
Now, on the second batch of two, using the remaining boards from the *only* batch of five boards, I'm using TMS320DM6467TZUTD1 chips. In the same condition, these immediately consume 24mA to 35mA to 45mA, at various times on various power-on tests. I've changed power supply programming resistors to produce 1.3V core voltage. I originally had a 33MHz crystal, but was unsure of oscillation, so I jumpered the circuit to operate off the 27MHz coming from the CDCE949 clock generator. So while the core voltage is higher, the clock speed is the same. In this current configuration, one of the boards immediately powers up to 30mA.
Note as well that the DM6467T chips get extremely hot on the surface (150+ degF), while I never noticed this with the DM6467 chips.
The original design was indeed for DM6467T, but the first batch didn't use them due to lack of availability.
QUESTION: Is there any way that the DM6467T is *supposed* to be drawing so much more current and generating so much more heat, or is this *perhaps proof* that there is a BGA assembly problem (another issue I'm considering).
Thanks very much,
helmut
Helmut,
Looks like there is a typo in the part number of your statment "....The first batch of three used TMS320DM6467ZUT1 chips....". The part number "TMS320DM6467ZUT1" is not a correct part number. Are you comparing DM6467ZUT Vs DM6467TZUTD1?
Regards, Srirami.
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Helmut Forren，
I'm using DM6467TZUTD1 too,It is very hot on my board.how can I do to reduce heat of DM6467TZUTD1.Note as well that the DM6467tZUTD1 Maintain the same performance as before. thank you.
Srirami,
Thanks for answering way back when. The first part was ZUT7 and the second ZUTD1. A couple months ago I discovered my problem was with having JTAG lines too long. On a THIRD batch using ZUT7, none worked. But when I went to serial port programming rather than JTAG, they all worked. So, presumably, the problem with the ZUTD1 boards was also this JTAG line situation. I can't confirm, however, because those boards got destructively tested.
What I've learned, and for others to know, is that those JTAG lines are persnickety. I was forced to run them off the board through a connector and FFC to another board. Design forces in the future won't allow that to happen, or else I'll just go straight to serial port programming (sfh_DM646x.exe).
jy h,
If your processor is working properly yet running too hot, then add more heat sink (in-board or above) or slow down the clock.
-Helmut
Thanks for the update and comments about JTAG lines. Did you check how these lines are routed on DM6467/DM6467T EVM?
Yes, mine were nasty compared.