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SN65HVD1050: SN65HVD1050 thermal issue

Stacey Yin
Prodigy 325 points
Part Number: SN65HVD1050
Other Parts Discussed in Thread: TCAN1051-Q1

my customer is using SN65HVD1050DR for the BLDC Driving Board and found when the board just power on, the IC temp will rise to 50c degree very soon which even hotter than the power IC. The system total consumption current around 40mA only at that time.

They want to know if this is normal behavior?  

  • 0
    TI__Guru 62920 points
    Hi Stacey,

    Heating of the device is not typical. Are you sure all of your circuit connections are correct? Is the device functioning as expected except for the heating? What else is connected to the CAN bus? Does the device cool off after the power is fully ramped up? Do you observe the same behavior across multiple units?

    Max
  • 0 in reply to Miguel Robertson
    TI__Guru 62920 points
    Stacey,

    Have you had a chance to look into any of the above questions or to further debug this issue?

    Max
  • 0 in reply to Miguel Robertson
    TI__Prodigy 325 points

    Hi, pls. see below feedback from customer

    Are you sure all of your circuit connections are correct? --> FAE check circuit correct.

    Is the device functioning as expected except for the heating? --> Function ok

    What else is connected to the CAN bus? -->please check schematics

    Does the device cool off after the power is fully ramped up? --> No.

    Do you observe the same behavior across multiple units? ---> Yes

  • 0 in reply to Stacey Yin
    TI__Guru 62920 points
    Hi Stacey,

    Thanks for the info. Is the TXD line toggling during this test? It looks like the typical power dissipation of the IC when TXD is toggling continuously is 170 mW, and so depending on the ability of the PCB to transfer heat the chip could be 20-30 C hotter than the ambient air. This could explain the 50 C reading, so I take back my statement that it isn't expected.

    It is unusual for a single node to transmit continuously, though, and so one other thing that would be good to check is the loading of the CAN bus. I see on the schematic that there is a 120-Ohm termination resistor between CANH and CANL; are there termination resistors on the other nodes on the bus as well? (Or, does the transceiver IC still heat up if this node is not connected to a CAN bus?)

    If the heating is a concern and cannot be resolved, you may want to consider switching to the newer TCAN1051-Q1 device. It is pin-for-pin compatible to HVD1050 and has improved performance. The power dissipation measured under similar conditions is significantly lower (52 mW rather than 170 mW).

    Regards,
    Max