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US 9,425,132 B2Granted
Stacked synchronous buck converter having chip embedded in outside recess of leadframe
AssigneeTexas Instruments Incorporated
InventorsOsvaldo Jorge Lopez, Jonathan A. Noquil
Life of this patent
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Abstract
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.
Claims10
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.
2 more elements
A method for fabricating a packaged device system comprising:
- providing a leadframe having leads and a pad with a first and a second surface, the first surface having a portion recessed with a depth and an outline suitable for attaching a semiconductor chip;
- attaching a first chip vertically on the second surface of the pad, a terminal of the first clip electrically coupled to the second surface;
- attaching a clip with a first flat side on the first chip, electrically coupled to a terminal of the first chip;
- encapsulating the clip, the first chip and the second pad surface in a packaging compound, while leaving the first pad surface un-encapsulated;
- and
- attaching a second chip with at least one second chip terminal is electrically coupled to the recessed portion of the first pad surface so that at least one of a second terminal of the second chip is co-planar with the un-recessed portion of the first pad surface and with the leads.
3 more elements
Dependencies are inferred from the claim text.