1.2 Effect of Output Slew Rate on GND Bounce

The slew rate (dv∕dt) of the output can affect GND bounce more than any other parameter. The slower the output slew, the lower is the GND bounce. This becomes a trade-off between performance and signal integrity. However, the frequency of the output does not affect GND bounce. The following figure shows the falling edge of a reference output (purple) in the high slew configuration, which is about 1.5V/ns, and a GND bounce pulse (green) of about 400 mV. The plot shows a GND bounce (green) of about 100 mV (note the changes in scale).

Figure 1-1. GND Bounce Plot with High Slew Output Reference

The only difference between Figure 1-1 and Figure 1-2 is the output slew rate, which is less than 0.75V/ns. This shows a 75% improvement when compared to high slew.

The following figure shows the falling edge of a reference output in the low slew configuration.

Figure 1-2. GND Bounce Plot with Low Slew Output Reference