Based on the placement and routing constraints, there might be a need to place ICs at a distance from the power sources for example regulators. The IC could be a Microcontroller, Transceivers and any other medium to high current drawing devices. In these scenarios, when the current drawing device needs an instantaneous current, an example scenario could be I/Os switching, then the power supply may not be able to supply that instantaneous current due to the inductance of the trace associated with the plane. Also, the trace adds some resistance. To compensate for this, a local bulk capacitor is required to supply that current. Such a capacitor is called Tank capacitor.
The value of Tank Capacitor depends on:
- Current to be drawn by the IC
- Voltage Rating
Typical Value of the bulk or Tank Capacitance can range from 1uF to 100uF.
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