Ground bounce
Under Ground bounce refers to an unwanted voltage -increase the on-chip ground at the . This increase in voltage is caused by the resistance and inductance of the bond wire . This is a special aspect of impedance coupling
The counterpart to the ground bounce is the so-called "V cc Sag". The same effect causes the supply voltage to drop briefly at the input.
Emergence
Ground bounce occurs when an output signal switches to low level or when the output has to actively drive a low level. The chip mass increases due to the current pulse when switching or a permanent high current to ground. Ground bounce can also be caused by an input signal. If an input signal is switched from low to high level, the inrush current for recharging the input capacitance has to be diverted to ground, whereby the ground level also rises.
Analogous to the ground bounce, V cc Sag is also created .
Effects
The increase in internal mass causes various errors:
- Unclean input and output signals (undershoot and overshoot).
- Degradation of the quality of analog signals.
- Deterioration in the effective resolution of AD converters.
- Unauthorized state transitions in chip-internal state machines . Usually leads to a crash.
- With a high ground bounce, the parasitic diodes of the pin become conductive, which also leads to malfunctions.
Web links
- Jeff Barrow, Reducing Ground Bounce (PDF; 649 kB) , (2007), Analog Devices
- Vikas Kumar, Ground Bounce Primer , (2005), TechOnLine (now EETimes).
- AN-640 Understanding and Minimizing Ground Bounce (PDF; 218 kB) , (2003) Fairchild Semiconductor, Application Note 640.
- Minimizing Ground Bounce & VCC Sag (PDF; 743 kB) , White Paper, (2001) Altera Corporation.
- Ground Bounce part-1 and part-2 by Douglas Brooks (PDF; 48 kB) , Articles, Ultra Cad Design.