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CSD88537ND: CSD88537ND Doubts

SHASHANK JAGADISH
Expert 1690 points
Part Number: CSD88537ND

Dear Community,

I understand the working of Mosfets in general but I have this doubt, Assume I have CSD88537ND 

And now I make the following connection

1. connect the pin 8 ( D1) to +24v 
2. connect the pin 2 (G1 ) to an MCU which can give 5v and 20mA for logic high
3. connect the pin 1 (S1 ) to a floating wire of a Car 

Here is what I want to achieve 

1. Pull the floating wire of car to +24v if i give logic high of 5v and 30mA from MCU pin
2. Pull the floating wire of car to GND if i give logic low from MCU pin - ( In This case D1 is connected to GND )

Will the above work ? Is my understanding of this mosfet working correct ?

If not can you suggest me a different mosfet  ? All I want to do is pull a floating wire of a car to VCC or GND from MCU via MOSFET !!
My mosfet should be able to able to handle pulsed current of 100A and continuous of around 20A, ( + or - is fine )

Regards

Shashank

  • 0
    TI__Guru** 114905 points
    Hi Shashank,

    Your post has been moved to the NexFET power MOSFET forum for better support.
  • 0 in reply to Rick Duncan
    Expert 1690 points

    Dear NexFET community,

    Kindly help me on this

    Regards

    Shashank

  • 0 in reply to SHASHANK JAGADISH
    TI__Mastermind 18200 points
    Shashank,
    The gate to source voltage of the MOSFET is what dictates whether the MOSFET is on or off.

    So if the source is floating, there is no saying what the gate to source voltage would be. The source either needs to be connected to ground or some stable voltage rail relative to the gate in order to turn the MOSFET on.

    Assuming you do turn the FET on, the source pin will not rise to VDS (24V rail) but rather the voltage drop across the FET will either drop (pulling the 24V down) or if the 24V is maintained, and the FET is fully turned on, it will push so much current through the FET that will be far more power than the device can dissipate and the FET will short.

    Finally, I would point out that this device is not logic level, so we do not recommend driving it with a voltage less than 6V gate to source.