What is the cause of overshoot?
Usage: Overshoot occurs when the transitory values exceed final value. When they are lower than the final value, the phenomenon is called “undershoot”. A circuit is designed to minimize risetime while containing distortion of the signal within acceptable limits. Overshoot represents a distortion of the signal.
How can I improve my undershoot?
Overshoot/undershoot can be reduced by a large off-chip output capacitor. If off-chip capacitor is not acceptable for the application, the overshoot/undershoot can be reduced by improving the loop bandwidth and/or by augmenting overshoot/undershoot reduction circuit.
What causes the overshoot and undershoot in an inverter?
These are caused by the gate-drain capacitances of the inverter transistors, which couple the steep voltage step at the input node directly to the output before the transistors can even start to react to the changes at the input. But i am still not so clear about input output coupling effect.
What causes overshoots on a simulated output signal?
Notice especially the overshoots on the simulated output signals. These are caused by the gate-drain capacitances of the inverter transistors, which couple the steep voltage step at the input node directly to the output before the transistors can even start to react to the changes at the input.
What causes the overshoot and undershoot in a PMOS?
However, there is gate-drain capacitance in that device (and also in the PMOS). So, the input signal is capacitively coupled to the output. The PMOS tends to shunt some of that coupling to VDD, but isn’t 100 % successful — thus the overshoot. Similarly, on falling edges, you see undershoot.
What happens when a CMOS receiver overshoots?
Thanks for your interest in High-Speed Digital Design. Overshoot can in severe cases cause CMOS latch-up and destruction of the receiver. Many CMOS receivers include built-in protection diodes on every input to preclude this possibility. Some don’t.