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DRV5057: DRV5057

Arup Mukherjee
Prodigy 10 points

Part Number: DRV5057

Tool/software:

I got this part  DRV5057A4 QDBZR from mouser electronics . The part is in SOT 23 package and 57A4 is etched on the chip.  When i connected the the to 5V DC and checked the ouptut pin by connecting an oscillosope we cant find and clock pulse at all. the output pin is low. while as per datahseet the output pin should give 50% duty cyycle 2khz clock. Currently no magnetic field is present. 

Then we pulled up the output put pin by 4k7ohm to 5v. the output pin was high at approximatey 5v . Still no clock was there.

The we changed the power to 3.3vDC from 5v dc the results were the same as stated above.

Please explain where am i wrong in interfacing or testing ??

The connections are as follows

1. VCC 5 / 3.3 V

2. Ouput 

3. GND

between pin 1 and 3 a decoupling ceramic capacitor or 0.1mfd /30VDC is connected.

Please help in resolving the issue.

Thanks in advance !!

  • 0
    TI__Mastermind 26230 points

    Arup,

    What is the output voltage when powered without a pull-up resistor?  Does it respond to any magnetic field while powered in this state? For example if the output is high, will it toggle low when a magnet is presented?  

    Are you able to measure supply current into the device?

    To confirm, the decoupling capacitor is 100uF? or 0.1uF?  If the larger value, can you try replacing to the smaller cap to see if reducing has any impact on power-up?

    Can you confirm that your pin connections follow the diagram below (top view)?

    Thanks,

    Scott

  • 0 in reply to Scott Bryson
    Prodigy 10 points

    Dear Scott,

    The voltage is zero volt when powered without a pull up.

    No it does not respond to any magnetic field. No change in state or clock when magnetic field induced by magnets.

    The supply current is in micro ampere.

    The decoupling capacitor is 0.1uF.

    The pin connection is exactly the same as shown in datasheet and in your email.

    We tried the other part also DRV5057A3 QDBZR but the results were the same. This also did not work.

    Please suggest what is wrong ?

    Regards

    Arup

  • 0 in reply to Arup Mukherjee
    TI__Mastermind 26230 points

    Arup,

    Is the device output under any sort of load? 

    Can you measure the impedance from:

    • Vcc to GND
    • OUT to Vcc
    • OUT to GND

    Can you send a scope capture of both Vcc and OUT during power on?  Is it possible to capture this with a fresh unit? If this is possible, please capture the entire Vcc Ramp.

    From your description, the part sounds like it may have been damaged.  You should see mA of current when the device is powered normally.  

  • 0 in reply to Scott Bryson
    Prodigy 10 points

    Dear Scott,

    The device is under no load !! the output oin is just connected to oscilloscope probe.

    The issue is that i imported  all these parts from Digikey and have tried 4 pieces but all yield same result !! Its just powered by 5V supply thays it . It should give a clock output without any magnet.

    dont know how to solve it.

    We are already using other hall sensors but none of then have any issues,

    we checked. the chip is not draining any current of large magnitude . just few micro amps.

    So where is the problem ?? please intervene as all chips imported cant be faulty !!

    Regards

  • 0 in reply to Arup Mukherjee
    TI__Mastermind 26230 points

    Arup,

    I agree, it is unlikely that you would get an entire batch of faulty devices.  All units are checked in production, so I would not expect a new unit to draw uA of current.  This would have been flagged in test. 

    By requesting an oscilloscope of your supply ramp, I was hoping to identify whether there were any unusual behaviors on the supply that might account for this. 

    • If there were excessive over-shoot, we might suspect that an over-voltage event may have occurred and possibly damaged the device. 
    • If the supply ramps excessively slow then I might recommend to try ramping the voltage more quickly to see if there was some subcircuit that did not initialize correctly.

    The fact that the device is not drawing current in the mA range suggests that:

    • The device is damaged by some sort of electrical over-stress (High input voltage or ESD) that results with an open circuit in the device
    • The device is not connected correctly (if VCC and OUT are swapped I measure less than 1uA, while I measured 6mA connected to 5V)

    Can you provide scope captures of your VCC and Output?

    thanks,

    Scott