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CSD88537ND: CSD88537ND - Reverse recovery time

LM
Prodigy 215 points
Part Number: CSD88537ND
Other Parts Discussed in Thread: TIDA-00196, TIDA-00197, TIDA-00261

Hi there,

I'm currently selecting a mosfet for my motor driver application. The only requirement that I'm not sure is the reverse recovery time trr for the bulk/body diode. 

This needs to be quite fast in the order of 10 ns. How do I know if this is fast enough? What is the reference value? 

I'm trying to compare this mosfet with another mosfet which has a trr = 12.5 ns for a reverse recovery charge of Qrr = 3.5 nC (di/dt = 100 A/us and If = 8 A).

The problem is the di/dt of the CSD88537ND is 300A/us for a Qrr = 50 nC and a trr = 30 ns.

I've done some research and it seems that the higher the slope di/dt, the lower is the reverse recovery time. Is this right?

This also needs to have a soft recovery but the datasheet doesn't provide enough data to determine this. 

Is this a good mosfet for my application?


Kind regards,

Laura

  • 0
    TI__Expert 7385 points

    Laura,

    Thanks for considering our devices.

    Yes the CSD88537ND is a good device for motor control. There are 3 motor reference designs on TI.com using this device,

    Ref Design Number Description
    TIDA-00196 12V and 24V Brushless DC Outrunner Motor Reference Design
    TIDA-00197 Speed-Controlled 24V Brushless DC Outrunner Motor Reference Design
    TIDA-00261 High Performance Bipolar Stepper Drive Stage Reference Design with 256 Microstep Support

    Qrr in the datasheet is very dependent upon the test conditions, please see article here :

    In addition there is a an article discussing selecting FETs for Motors here:

    I assume you are concerned about Qrr for the losses generated.

    We have developed a tool that will calculate the losses in a motor, you can download the tool here: