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LMG5200: Allowable transient switch node current

Part Number: LMG5200

The part is marketed as a "10 A" Half-bridge power module. Yet, the abs. max. rating mention 10 A as the unconditional switch node current, which would turn it rather into a "5-6 A" half-bridge module when accounting for realistic transient safety margins.

Currently, I am having difficulty during design to keep the startup current below 10 A in a 50 V application into a 4.7 µH inductor, even when carefully ramping up the duty cycle at fSW ~ 1 MHz. The current is often seen to peak to ~15 A for about 100 µs.

Is this "10 A" max. rating to be understood as a DC thermal destruction figure ? The datasheet gives no SOA for transient currents.

My gut feeling is that this is absolutely usual and even fine thermally, but it is a step over the abs. max. ratings, so I thought I'd ask here for an opinion...

  • Hello Lutz,

    Exceeding 10A during transients is not a problem; you could go significantly higher than the 15A you mention if needed.

    There's a few limits on the device max current:

    1. Thermal. Generally not an issue for transients (excluding shoot through)

    2. Electro migration. Definitely not an issue for transients. This is where the 10A datasheet limit comes from.

    3. Inductive energy / ringing. Can be an issue for transients, depending on Vin, Iout, & layout.

    Thanks,

    Travis