* Question
| Analysis of the heat dissipation function of the heat sink, what characteristics can be found? |
* Answer
| • When the wafer substrate is operated at a clock rate of 100 MHz or more, a large amount of common mode current is generated in the device package.• The decoupling capacitor eliminates only the differential mode RF current between the power supply and ground.• Some ceramic package devices have pads on top for further differential mode decoupling.Therefore, the heat sink is placed on top of the component package so that the physical distance of the metal plate from the ground plane (y) is closer to the wafer (x) in the package.• When a metal heat sink is placed on top of the component, a zero volt reference (image plane) is provided closer to the wafer than the image plane on the PCB. |
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