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DRV8811: Issue with DRV8811

mf101
Prodigy 105 points
Part Number: DRV8811
Other Parts Discussed in Thread: DRV8818

In one of our products we use DRV8811 chips  to control stepper motors. We faced some issue with these chips in the past, where the driver "locked up" and motor movement ceased to work properly. It looked like the driver was not able to perform steps anymore. A power reset was required to get out of this state. Some time after the erroneous behaviour was discovered, we received the information from TI, that the issue was caused by a silicon bug. We replaced the chips with newer silicion revision (date code newer than 98TC -> production after 08/2009) and there has never been any problem in the meantime. All of our devices undergo long-term testing (3 days at minimum) before shipment.

Just recently, after several days of runtime during long-term testing, some of our devices showed the erroneous behaviour again. The marking on the chips is 54TC DLQ8 respectively 52TC AHK5. Is the production year 2015 or 2005 ?

If it is 2015, was anything changed inside the chip that might explain the re-apperance of the issue ?

Devices failed in customer applications already and we need to ship new products in the next days. Therefore timing is very critical, and we need clarification on this issue as fast as possible.

  • 0
    TI__Expert 4650 points
    Hello,

    We will look into this and get back to you as soon as we have a response from our team.
  • 0 in reply to Phil Beard
    TI__Expert 4435 points
    Hello,

    We are still looking into this. In the meantime, could you please describe what are the Output pins seeing and what is the voltage for VMA and VMB? Also, what is the input control signal voltage? Thank you very much.
  • 0 in reply to Luis Riveros
    Prodigy 105 points

    Thanks for responding. Please find details about how we operate the chip in the following.

    Voltage levels:
    VMA/VMB = 24V
    VCC=3.3V
    USM0/USM1 = 3.3V
    DECAY/SLEEP/SR = 3.3V
    STEP/DIR=3.3V

    Circuit:
    RCA/RCB = 27K || 1nF to GND
    ISENA/ISENB=1Ohm||1uF to GND
    Between AOUT1/AOUT2 and BOUT1/BOUT2 we attach a snubber circuit (10Ohm in series with 470pF).
    All capacitors are sized as suggested in the datasheet (CP1-2/VCP/VGD = 220nF, VMA/VMB = 100nF||1000uF, VCC=100nF).

    Layout:
    The chips are properly attached to GND, signals lines to the passive components are short (<4mm), thermal aspects have been considered (via array under chip with copper flooded area).


    Investigations we made so far:
    We heated up the chips with a hot air gun, without any effects. Therefore we conclude, that the issue is not related to thermal performance.

    It looks like one phase is completely lost in the erroneous case, while the other one is still working (e.g. no current drive through the winding A while winding B looks normal). We observe holding torque, but the motor only moves into one direction (predominant direction, caused by gravity) when the driver receives a step signal. The movement occurs with larger step size than usual.

    A power reset helps to recover, but is not a solution for us. Our devices have to run continously in industrial environment. Resetting the chip by pulling the RES line low does not help in most of the cases. So far, we only experienced one case where the chip recovered after 20 resets.

    Below are two measurements, both measured between OUT1/2 of the two phases. The first measurement shows the lost phase, the second the working phase.

  • 0 in reply to mf101
    Prodigy 105 points
    In the following thread from 2011 two users also experienced similar issues:
    e2e.ti.com/.../385678

    The issue came up in 2008/2009 in our case and as mentioned before, we never had any problems in the meantime.

    Maybe have received devices with old silicion revision again. Since our production line is stopped and we face severe time pressure, we ordered new 8811 devices today. What we need is a general approach to identify and sort out erroneous devices before they get mounted on the PCBs. Is there any possibility to deduct this information from the marking ?

    In addition we also ordered 8818 devices, which seem to be a compatible replacement option. Could you please confirm that the 8818 is a compatible replacement and tell us if it is also affected from the silicon bug of the 8811 ?
  • 0 in reply to mf101
    TI__Expert 4435 points
    Hello,
    Thank you very much for the information provided. We are in the process of identifying if the devices are from an old silicon revision but we are unable to trace the 54TC marking. Could you please kindly send a picture of this device? If you prefer you can send it through a private message.
    Thanks again.
  • 0 in reply to Luis Riveros
    Prodigy 105 points

    Could you please answer my questions regarding the 8818 ? If it is compatible and not affected by the silicon bug, we will replace the 8811 with this part. At least for the current PCB batch.

    Below are the pictures you requested.

  • 0 in reply to mf101
    TI__Expert 4435 points

    Hello,
    Thank you for the pictures. We have not been able to track the 54TC marking. The 52TC is not from 2005 since this part was released in 2008. We would like to have these parts back to do a test analysis. Please work with your distributor to start the return process. I sent you a message with my information.
    As far as your question, the DRV8818 devices are not affected by the bug of the DRV8811 old silicon. Thank you very much.

  • 0 in reply to Luis Riveros
    Prodigy 105 points

    Thanks for the response. I forwarded the return request to our production team. You will receive information if they take action.

    As I conclude, right now the DRV8818 is the only safe option to get our devices working. We are currently performing long-term tests with these motor drivers to get them ready for shipping as fast as possible.

    Is there any way to figure out from the marking if DRV8811 devices are affected from the bug ?

     

  • 0 in reply to mf101
    TI__Expert 4435 points
    Hello,

    The 52TC marking has the latest silicon revision and should not have the old bug.
    We could not track devices with 54TC marking. Counterfeit of part is very unlikely but a possibility since no records are shown. We will be able to determine this if we get parts back for testing. Thank you very much.
  • 0 in reply to Luis Riveros
    Prodigy 30 points
    Sorry to intrude, but I too have this date code 54TC C7YD, so I will be interested in this outcome.
  • 0 in reply to adrian grace
    TI__Expert 4435 points

    Hello Adrian,

    What problems are you facing with the DRV8811 devices? Can you please describe it?

  • 0 in reply to Luis Riveros
    Prodigy 30 points
    Hi Luis.
    I was interested in this comment..
    We could not track devices with 54TC marking. Counterfeit of part is very unlikely but a possibility since no records are shown. We will be able to determine this if we get parts back for testing. Thank you very much.

    I was also interested in the coding used on the device itself as i could find no explanation as to what 54TC C7YD means.
  • 0 in reply to adrian grace
    TI__Expert 4435 points
    Hello Adrian,
    The 54TC is only a part of the device marking. Your marking provided 54TC C7YD is different from the one originally posted, 54TC DLQ8. Although the date is the same there is more information on the marking which are different as stated before.
    Explanation for the device markings can be found in this app report, www.ti.com/.../szza020c.pdf
    Format 2 would apply to your device.
    My question is if you are experiencing any problems with your device please describe it. If the problem is not the same as the original question, please start a new thread for better support. Thank you very much.