用英文详细介绍CMOS反相器的输入输出特性

The CMOS inverter is a fundamental building block in digital circuits, offering high noise immunity and low static power consumption. It consists of an n-channel MOSFET (nFET) and a p-channel MOSFET (pFET) connected in series, with their gates tied together. When the input voltage is low, the pFET is on, and the output voltage is high. Conversely, when the input voltage is high, the nFET is on, and the output voltage is low.

The voltage transfer curve (VTC) of a CMOS inverter shows the relationship between the input voltage (Vin) and the output voltage (Vout). When Vin is less than the threshold voltage (Vt), the pFET is on, and Vout is approximately 0V. When Vin is greater than (Vdd - Vt), the nFET is on, and Vout is approximately Vdd.

The inverter also has certain DC characteristics, such as the low-level output voltage (VOL) and the high-level output voltage (VOH). VOL is the output voltage when the output is at a logic low level, and VOH is the output voltage when the output is at a logic high level. The ideal inverter has VOL = 0V and VOH = Vdd, but in practice, there are some voltage drops due to the finite on-resistance of the transistors.

Noise margins are crucial for the reliable operation of CMOS inverters. The noise margin for the low level is the difference between the threshold voltage and VOL, and for the high level, it is the difference between VOH and Vdd.

The CMOS inverter\'s load characteristics show that the output voltage is dependent on the load current. The inverter can be considered as a current source with a voltage-dependent output impedance. The output voltage decreases as the load current increases.

The rise and fall times of the CMOS inverter are determined by the charging and discharging of the load capacitance through the transistors. The propagation delay is the time it takes for the output to change from one logic level to another after the input has changed.

For a more in-depth understanding of the CMOS inverter\'s input-output characteristics, you can refer to the detailed sources provided, including academic papers and electronic engineering references.