fz2101
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Hello everyone,
I'm using a QFN package with exposed paddle, i.e., the bottom of the package is a big ground plane and can be directly contacted to the PCB ground plane. This allows me to downbond the "Gnd" pin to the ground plane and thus achieve a small bondwire inductance, L_Gnd, of 1nH, let's say.
On the die, Vdd and Gnd pins are right next to each other. If I don't downbond, then the Vdd and Gnd bondwires run in parallel to each, and because of the opposite direction of the current flow, the inductance of both are reduced (by the mutual inductance).
So my question is, which bonding scheme is better? 1. Downbond Gnd ----> large L_Vdd, small L_Gnd 2. Do not downbond -----> medium L_Vdd, medium L_Gnd
Thanks,
frank
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