Hi, I'm using the National/TI LM9061 power MOSFET driver in a part used for aftermarket applications to drive an N-channel power MOSFET in a high-side configuration. One problem I have is when customers ignore instructions and try to connect the part without turning off the power first (usually by disconnecting the battery), and then connect the part's +12V input and output lines before connecting the ground lead. When this happens, the power MOSFET's gate is floating, and if a low-resistance load is connected to the output line, current is conducted through the MOSFET, but at a high on-resistance, causing the MOSFET to heat up excessively and damaging it internally, rendering the device useless. Do you know any way to keep the MOSFET gate from floating when the ground connector is not connected? I've found that tying the MOSFET's gate and source pins together prevents the problem, but of course this also renders the device useless during normal operation; I also tried using various resistors between these pins to prevent the gate from floating, but that didn't work; a low enough resistance to prevent floating was so low the LM9061 was unable to drive it. Any tips would be greatly appreciated; I realize that in OEM applications, a wiring harness prevents this kind of condition, but in the aftermarket customers generally prefer fast-on terminals.
Also, do you have any advice regarding the LM5060 as a possible replacement or upgrade to the LM9061? Would that be a better part for future designs? Currently, it seems to be quite a bit more expensive.
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