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DRV8703D-Q1: About GND Pins

Yuta Nishie
Genius 4955 points
Part Number: DRV8703D-Q1

Tool/software:

Hi,

The customer is using DRV8703DQRHBRQ1.

1. Could you tell me if each GND pin (1 and 13, 17, and 25 pins) is conductive?

When the customer checked the conduction of each pin with a tester, the following results were obtained. Is this result correct?

・Pins 1 and 17 were conductive. (Resistance value displayed on the tester is 0 Ω)

・Pins 13 and 25 were not conductive. (Resistance value displayed on the tester is high.)

2. Also, if pins 13 and 25 are open, what will happen to the IC operation?

Best Regards,

Nishie

  • 0
    TI__Genius 11691 points

    Hi Nishie,

    Thanks for the question.

    Our device expert is out of office. Please give him a couple of days to respond.

    Thanks,

    ibinu

  • 0 in reply to Ibinu Alaudeen Nadeera
    Genius 4955 points

    Hi Ibinu-san,

    Thank you for your reply.

    If there is an update, please let me know.

    Best Regards,

    Nishie

  • 0 in reply to Yuta Nishie
    TI__Mastermind 44475 points

    Hi,

    Thanks for the question. Will feedback to you in a day or two.

    regards

    Shinya Morita

  • 0 in reply to Shinya Morita
    Genius 4955 points

    Hi Shinya-san,

    Thank you for your support.

    Could you give me an update on what you are doing? 

    Best Regads,

    Nishie

  • 0 in reply to Yuta Nishie
    TI__Mastermind 44475 points

    Hi Nishie san

    As customer mentioned, DRV8703D-Q1 has some difference among GND pins. I could confirm it. I need to wait further checking result on the bench to response.

    regards

    Shinya Morita

  • 0 in reply to Shinya Morita
    Genius 4955 points

    Hi Shinya-san,

    1. Is it correct to understand that "slight difference in GND pins" is the same as what the customer confirmed?

    Or is it correct to understand that you plan to confirm the slight difference in bench test? I am sorry to trouble you, but I would appreciate it if you could confirm it.

    2. Also, if pins 13 and 25 are open, what will happen to the IC operation?

    Best Regards,

    Nishie

  • 0 in reply to Yuta Nishie
    TI__Mastermind 44475 points

    Hi Nishie san

    Thank you for your questions. Let me feedback to you when bench test is completed.

    regards

    Shinya Morita

  • 0 in reply to Shinya Morita
    Genius 4955 points

    Hi Shinya-san,

    I would appreciate it if you could contact me when the bench test is completed.

    Best Regards,

    Nishie

  • 0 in reply to Yuta Nishie
    TI__Mastermind 44475 points

    Hi Nishie san,

    Looking for resource to have test. Will feedback to you when it is available.

    regards

    Shinay Morita

  • 0 in reply to Shinya Morita
    TI__Mastermind 44475 points

    Hi, 

    Let me add my feedback in Blue.

    1. Could you tell me if each GND pin (1 and 13, 17, and 25 pins) is conductive?

    Not all conductive together. Pin 1,13,17 are connected interlay in device. Pin25 is not.

    When the customer checked the conduction of each pin with a tester, the following results were obtained. Is this result correct?

    ・Pins 1 and 17 were conductive. (Resistance value displayed on the tester is 0 Ω). Yes, your customer's test data makes sense.

    ・Pins 13 and 25 were not conductive. (Resistance value displayed on the tester is high.). No, your customer's test data makes sense.

    2. Also, if pins 13 and 25 are open, what will happen to the IC operation? 

       As Datasheet recommended, 13 and 25 should be connected to system GND together with pin 1/13/17/25 pin.

       However, 

        -If 25pin is OPEN (by soldering issue etc), no damage should happen on device. No impact to functionality.

        -If 13pin is OPEN(by soldering issue etc), no damage should happen on device. No impact to functionality.

    regards

    Shinya Morita

  • 0 in reply to Shinya Morita
    Genius 4955 points

    Hi Shinya-san,

    Thank you for taking the time to conduct the test.

    Shinya Morita said:
    -If 25pin is OPEN (by soldering issue etc), no damage should happen on device. No impact to functionality.

    →It is not connected to the device inside, but what function does the 25 pin have? Also, if it is open or NC, could you tell me what kind of condition the device is expected to operate? For example, does the input current decrease?

    Shinya Morita said:
    -If 13pin is OPEN(by soldering issue etc), no damage should happen on device. No impact to functionality.

    →Could I check if your answer is a mistake? Since the 13pin is connected to the device internally, I think there will be damage to the device if it opens. Is it correct that there is no damage?

    Best Regards,

    Nishie

  • +1 in reply to Yuta Nishie
    TI__Mastermind 44475 points

    Hi Nishie san

    25pin has internally connected to silicon, however there is no function on 25pin for customer use. Therefore, If 25pin is left OPEN on PCB, no impact functionally.

    13pin is internally connected to silicon and it is GND line on silicon. Even if GND (13) is not connected (by error, soler issue etc) externally, DRV still have 1 and 17 connections to PCB GND externally. Therefore, functionally working and no damage happens. 

    regards

    Shinya Morita

  • 0 in reply to Shinya Morita
    Genius 4955 points

    Hi Shinya-san,

    Thank you for explaining the 13pin and 25 pin.

    There is a problem with the customer's 25 pin terminal floating. Could you tell us if the following is related to the 25 pin? If not, could you tell us the possible cause? The motor does not work and the product is defective.

    < Symptom >

    When the power is turned on (when the motor is not running), the input current is about 37 mA, and then the motor does not work.

    When the 25 pin is not floating, the input current is 48 mA when the power is turned on, and then the motor works.

    When the 25 pin is connected to the PCB, the input current is 48 mA.

    X-rays and visual inspection confirmed that all the pins except the 25 pin are connected to the PCB.

    Best Regards,

    Nishie

  • 0 in reply to Yuta Nishie
    TI__Mastermind 44475 points

    Hi Nishie san,

    Basically, 25pin should be connected to GND.  This is TI's position. 

     "37mA and motor does not work" happens on multiple unit? Or only one specific unit? If multiple unit, this could be just device behavior. 

    regards

    Shinya

  • 0 in reply to Shinya Morita
    Genius 4955 points

    Hi Shinya-san,

    Shinya Morita said:
    Or only one specific unit?

    It occurs in multiple unit.

    What is the other expected behavior when the 25 pin is open? I would like to know the expected behavior because I would like to test the electrical characteristics to confirm the terminal floating of the IC mounted on the mass production board.

    Best Regards,

    Nishie

  • +1 in reply to Yuta Nishie
    TI__Mastermind 44475 points

    Hi Nishie san,

    Thank you for your feedback.

    25pin should be connected to System GND together with other GND pins. This is required on Datasheet.

    regards

    Shinya Morita