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73 Threads found on Voltage Inversion
If you tie source and drain together, and you ensure that vgs is always higher than vth, the oxide capacitance will dominate since the transistor is ON and in triode. It is helpful for supply rails when you will have a high voltage already and the oxide of the NMOS will have a good capacitance density.
Consider that the high impedance DR is coupled to low impedance voltage source by impedance inversion of 1/4 wave to understand basics. This conversion from M to E field with high Q resonator is enhanced with the Q of the 1/4 wave resonator coupling.
Hi, guys I have problem with P_DIOD design, as you can see to set this device to strong inversion ( gmoverid near to 10) I choose W/L= 1/12, problem is that this p_diod have large vds=720mV a therefore less voltage left fo DIFF_PAIR which is going to triode and Gain of this OTA is going to hell. 108730 So I can
Hello all, I am using cadence umc 180nm technology. I want to replace MIMCAP from my circuit because of huge area. currently I am simulating with MOSCAP with the same size but in simulation capacitor value giving very small (Instead of 500pF its showing 12pF).voltage applied range is from 300 mV to 500mV. Please suggest me how to use and if pos
Hi all, What are the challenges in designing a voltage reference in deep submicron CMOS process? To my knowledge, CMOS voltage reference are designed on the basis of vertical/lateral BJTs and MOSFETs in weak inversion, and they are adopted to emulate the behavior of real BJT. But is there any non-ideal factor/characteristic in these (...)
In CE configuration output is collected at collector terminal,charge carriers take some time to travel from input to output terminal(equals 180 phase shift) Please, convince yourself before answering. Explanation for the phase inversion: Increase in signal input voltage (Vbe increase)
Yes the Cgs capacitance is voltage dependent capacitance. Hope the following references will help: 1) Chapter 2, Section 2.4.2 Mos Device Capacitance Page No: 29 from the book 2) The voltage-dependent capacitors[
Hi all, I'm designing an OTA in weak inversion using cadence. I found the threshold voltage of each transistors working in weak inversion are different and they are also changing with applied gate-source voltages. Does anyone know how it happens? Thanks in advance!
The question here is that, would the AC voltage across the R5 affect the GND's voltage potential How can a voltage across R5 affect a ground potential? You have to assure that ground is actually the common potential of your circuit, also that the current flows into the resistor. Regarding intended intended halfwave rectification
... and qb i have connected to vdd. It is not allowed to connect an output to a fixed voltage. Often, the other output q is generated by inversion of qb. Unused outputs have to be left open!
Dear friends I have used the MOS as a capacitor. I am running it under the saturation strong inversion region. I have attached you this picture from Jakob Baker book. He told that in order to use the MOS a capacitor it must work in the strong inversion because it has less or no voltage dependency as shown in the graph. However, the (...)
I have designed a opamp based voltage peak detector. As shown in the diagram below. however the output voltage only follows the input I thought i had the cap sized right to hold the value longer. The input wave is only about 1ns or smaller pulse is the
In common emitter circuits an increase in Base voltage causes a decrease in Vout and a decrease in Base voltage produces an increase in Vout. I`ve got the impression that Andrew would like to know WHY there is a phase inversion. The answer is simple: An input voltage increase causes an increase in th
Dear all after long time of dealing with op-amp design still I am stuck with many basic things, I found my chance in this forum to ask you about it... how could i know if my op-amp is working in the strong inversion or in the weak inversion??, i read from many resources that i have to check the overdrive voltage if it is below 50 mV (...)
I read in article that "At short channel lengths the halo doping of the source overlaps that of the drain, increasing the average channel doping concentration, and thus increasing the threshold voltage. This increased threshold voltage requires a larger gate voltage for channel inversion. However, as channel length is (...)
I read that in an n-mosfet, when drain voltage is increased above threshold (in saturation mode) the inversion channel between the source and drain is pinched-off near the drain region. so the channel length decreases and so its resistance. so larger current flows through the channel. My doubt is, when a smaller portion is pinched off near the dr
Hello guys. i am designing a OTA in weak inversion... and the voltage gain looks good but the gm behavior shows very low values at low frequencies it this normal? I calcuate that from the ratio of the output current over the voltage input. It this correct? 73483 its only for gathering the idea for weak inversion
when we decide to select over drive voltage according to some reference we must choose it's minimum value around 0.15-0.2 (strong inversion)for critical condition.but others don't attention to this subject and so select the transistors over drive voltage to operate only in inversion(moderate or near the weak inve
I'm designing an integrated cap-less LDO in 45nm so the W/L ratio of my pass transistor can be quite large without too much area penalty. Is there any reason, why all the LDO designs I've seen have relatively high dropout voltages in the range of 100mV+? Of course, the transient response and compensation will suffer. But how come there is no LDO on
No, it will not change what you say. What it means is this: When the input voltage of a CE amplifier increases, the output voltage decreases, and vice versa. An audio signal is a voltage that's changing constantly in strength (voltage) and direction. If you feed that to the input of a CE amplifier, it will cause the (...)