Why Is Ground Bounce Bad?

2018-11-28 13:52Writer: qyadminReading:

     The bad of Ground Bounce


       Right now that the input changes state, the output and MOSFETS are no lengthier in a defined state—they are somewhere in between. The result might be false switching or double-switching. Additionally, every other parts on the IC die that reveal the same Gnd and Vss connections will be impacted by the switching event.
 
      Nevertheless the effects of surface bounce aren't limited to the IC die. Just as ΔVB forces the MOSFET source potential above 0V, it forces the circuit Gnd potential below 0 V. Most of the images you see depicting bounce demonstrate outside effects.
 
      If you have several gates switching at the same time, the effect is compounded and can completely disrupt your routine.
 
      You can see jump in the examples below.
 
   Significant Gnd and Vss bounce is shown in Figure 2 in a signal line from the BeagleBone Black computer with the LightCrafter cape attached and activated.
 
   Here, roughly ~1V of noise is developed on a 3. 3V line during transitioning that continues to resonate appreciably in the sign lines before eventually slipping to the background line noise.
 
 
Why Is Ground Bounce Bad?
 
 
  Figure 2. A transmission line from the BeagleBone Black with the LightCrafter cap attached and activated.
 
  The noise is not limited to the entrances that are switching. Typically the switching gates link to the ICs power pins, and PCBs often reveal common power and surface rails. That means that the noise is easily communicated to other places in the circuit either through direct electrical connection via Vss and Floor on the die or coupling of the footprints on the PCB.
 
 
Why Is Ground Bounce Bad?
 
 
   Figure 3. This image is captured from the BeagleBone Black with the LightCrafter cape attached.
 
  In Determine 3, Channel 2 (shown in cyan above) shows ground and Vss bounce in an undamped transmission line. The problem is significant enough that it telegraphs through to an alternative signal line on Route 1 (shown in yellow).
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