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Original question:

SN65HVD1050: SN65HVD1050 thermal issue

SN65HVD1050: HVD1050 surge test damage

Hangjie Wang
Intellectual 910 points
Part Number: SN65HVD1050
Other Parts Discussed in Thread: HVDA551-Q1

Hi team,

When my customer used HVD1050 for surge test, he found that when CANH and CANL add negative 2kV surge to ground, HVD1050 will be damaged, and the impedance of CANH and CANL to ground will decrease, but this problem will not occur when replaced with HVDA551. Could you please help with the following:


1. The difference between HVD1050 and HVDA551 CANH and CANL internal circuits.


2. Analyze why HVD1050 will be damaged based on the following test waveform？

The following are the CANH to GND test waveforms before the two HVD1050s are damaged

  • 0
    TI__Guru 66692 points

    Hangjie,

    The SN65HVD1050 was not designed to meet the same Automotive EMC standards that the HVDA551-Q1 was designed to pass. That includes integrated ESD protection, and that is likely what is showing here. The HVDA551-Q1 has better integrated ESD protection specified by IEC that is closer to what a surge waveform looks like when comparing to HBM ESD which the SN65HVD1050 is only designed to meet. 

    In general, I'd recommend moving away from the SN65HVD1050, as it is a much older device, and there are upgrades to it in the SN65HVDA1050A that was designed to passed the automotive EMC standards previously mentioned. All of that being said, is there a reason the customer isn't using one of our TCAN devices?

    Regards,

    Eric Hackett 

  • 0
    TI__Intellectual 910 points

    Hi Eric, 

    Thanks for your quick reply, Could you please attach the internal structure diagram of the two chips? I found on DS that the inside of 1050 seems to be a diode, and the inside of 551 is a TVS.  Is it related to this? In addition, the customer is using the 1050A version, because some old projects are using 1050 and cannot be replaced now.

  • 0 in reply to Hangjie Wang
    TI__Intellectual 910 points

    Whether the external characteristics of 1050 and 551 are inconsistent when powered on, because I found that CANH has oscillating waveform to GND during the surge test.

  • 0 in reply to Hangjie Wang
    TI__Guru 66692 points

    Hangjie,

    I cannot share the internal structure of the die because this is a public online forum, and that is proprietary information. Is the 1050A version also showing the issue, or just the 1050?

    These are two completely different CAN bus designs, so there should be expected differences in voltage transient testing. Which device shows the oscillating waveform?

    Regards,

    Eric Hackett