06-09-2017, 01:15 PM
Complementary MOSFET (CMOS) technology is used today widely in the day to form circuits in the various applications. Nowadays computers CPUs and cell phones make use of CMOS due to several key benefits. CMOS offers low power dissipation, high high speed, high noise margins in both states, and operate over a wide range of source and input voltages (provided the source voltage is fixed). Next I'll try to explain how this logic gate works now that it has an idea of how important CMOS is in your everyday life.
CMOS Inverter Basics
As can be seen in Figure 1, a CMOS circuit is composed of two MOSFETs. The upper FET (MP) is a PMOS type device while the lower FET (MN) is an NMOS type. The effect of the body is not present in any of the devices and that the body of each device is directly connected to the source of the device. Both doors are connected to the entry line. The outlet line connects to the drains of the two FETs.
Take a look at the VTC in Figure 2. The curve represents the output voltage taken from node 3. You can see what the CMOS circuit works as an inverter by noting that when VIN is five volts, it is zero and vice versa. Therefore, when entering a high you get a low and when you enter a low you get a high as expected for any inverter. You might be wondering what happens in the middle, curve transition area. You may also be curious as to what modes of operation the MOSFET are in. Let's see these topics below.
CMOS Inverter Basics
As can be seen in Figure 1, a CMOS circuit is composed of two MOSFETs. The upper FET (MP) is a PMOS type device while the lower FET (MN) is an NMOS type. The effect of the body is not present in any of the devices and that the body of each device is directly connected to the source of the device. Both doors are connected to the entry line. The outlet line connects to the drains of the two FETs.
Take a look at the VTC in Figure 2. The curve represents the output voltage taken from node 3. You can see what the CMOS circuit works as an inverter by noting that when VIN is five volts, it is zero and vice versa. Therefore, when entering a high you get a low and when you enter a low you get a high as expected for any inverter. You might be wondering what happens in the middle, curve transition area. You may also be curious as to what modes of operation the MOSFET are in. Let's see these topics below.