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SN754410: Recommended inductive load

Part Number: SN754410

I'm using this device to power an inductive device, however, the recommended inductive load for the chip is not specified in the datasheet. What is the recommended inductive load this device should interact with?

  • Hi Tom,

    There is no recommended inductive load. The device is designed to control bidirection currents up to 1A.

    What are you trying to drive? There are other devices that may be a better fit.

    Rick Duncan
    Motor Applications Team

  • In reply to Rick Duncan:

    Hi Rick, thanks for the response.

    I'm using the chip to drive 4 magnetic particle brake (PWM signals into chip pins 2, 7, 10, 15, brake signals from pins 3,6,11,14). The spec sheet says that the chip is designed to drive inductive devices, so I have small inductors (10 microHenry) at each output, between the driver and the brakes.

    The reason I'm posting this question is because each brake draws a maximum of 220 mA, far below the drivers stated 1A continuous per channel, but for some reason the driver gets really hot during operation. My circuit behaves exactly as I intended, but the heat under normal operating conditions has me worried that I'm doing something wrong.
  • In reply to Tom Augenstein:

    Hi Tom,

    Although the device is designed to drive inductive loads, the device can also drive resistive loads. You may not need the small inductors at each output.

    How are you determining the current in the brake?
    If the driver is getting hot, do you have the proper connections to pins 4, 5, 12, and 13 to dissipate the heat?

    Rick Duncan
    Motor Applications Team

  • In reply to Rick Duncan:

    Hi Rick,

    Thanks for the response, and I figured out the issue. I went back to the original pcb design the device is mounted to and saw that the ground/heat sink pins were routed through a common wire to ground instead of a wire for each pin, as the datasheet calls for. I wired up a new circuit with independent ground connections for each of the four device ground pins and now driver works great and no longer heats up during operation. Looks like you were right.

    Interestingly, when I put small inductors in series with the driver outputs I get better results. However, this improved performance is subtle compared to the improvement seen by proper grounding.

    Thanks,

    Tom

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