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LMZ31704 / Bottom pad

Other Parts Discussed in Thread: LMZ31704


I know that LMZ31704 has bottom pad, VOUT(41 pin) and PH (42 pin). Now I plan to replace it on EVM because it was damaged, but then the solder machine can't solder bottom pad. I understand that the thermal performance will be decreased if the bottom pads are not soldered, but I believe that it will be no problem electrically. Is my understanding correct? I also know that 10 pin (PH) is connected to bootstrap diode internally, so it must be connected other PH pin on PCB.

Best Regards,

Sonoki / Japan Disty

  • Yes, the bottom pads, 41 & 42 are connected internally to the pins on the perimeter of the device. The pads are required for thermal relief, however the device should operate electrically.
    See app-note #SLTA069 for information on removal and rework of these devices. By cleaning the pads and applying solder paste, the device can be re-soldered down to the pads during reflow.