Stacked synchronous buck converter having chip embedded in outside recess of leadframe

摘要

A system has a leadframe with leads and a pad. The pad surface having a portion recessed with a depth and an outline suitable for attaching a semiconductor chip. A first chip is vertically stacked to the opposite pad surface. A clip is vertically stacked on the first chip and tied to a lead. A second chip has a terminal attached to the recessed portion and terminals co-planar with the un-recessed portion. A second chip is attached to the clip.

主权项

1. A system comprising:
a leadframe having a plurality of leads and a pad with a first and a second pad surface, the first pad surface having a recessed portion and an un-recessed portion, the recessed portion having a depth and an outline suitable for attaching a device, the pad tied to a terminal of the system; a first chip vertically stacked to the pad, the first chip having at least one first chip terminal attached to the second pad surface; a clip vertically stacked on the first chip, the clip having a first flat side attached to a source terminal of the first chip, the clip tied to a lead from the plurality of leads as a grounded output terminal of the system; and a second chip vertically stacked on the first chip, the second chip having a second chip terminal attached to the recessed portion of the first pad surface and further having a plurality of terminals co-planar with the un-recessed portion of the first pad surface.