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# Current Noise Transistor

47 Threads found on edaboard.com: Current Noise Transistor

## [Moved]: noise in high Vth and low Vth FET

Yes, you are right, they should be compared with the same Vov voltage. I just use the same Vgs to bias the high Vth and low Vth transistor, and then observe the thermal noise in the current mirror configuration from them. The thermal noise equation is: in^2=KT*(gm)/3. For the low Vth device has higher Vov, with the same (...)

## Very Low Differential voltage amplification

No real idea for the moment about the voltage or current noise. Perhaps you should review the transistor data of your design kit. You can calculate expectable voltage and current noise for specific transistor size and drain current.

## what's the minimal input current for the Ib current of NPN transisor?

Can the input base current to be as low as 1pA for the npn transistor? Then what's the typical current gain for such low base current? thanks.

## Transistors as diodes

The emitter-base junction of a transistor has a reverse-biased avalanche breakdown at 5V to 7V and is not robust to handle the breakdown current so the transistor will be damaged. Then maybe the base-emitter should be shorted to make a diode.

## calculating resistor to use with transistor pins

Hi, We can't givd you a valid answer because there are a lot of informations missing. One can use a transistir in maby different ways. * it could be a voltage amplifier * current amplifier * temperature sensor * power switch * and many other things Each of the above needs another circuit = connection to other electronic parts like resistors, cap

## Problem with Inverter

You can also add a snubber circuit near to each switching device. This will reduce the peak current flowing inside during opening period. Another possibility, but it's kind of hard to evaluate without a notion either of the waveform or the board layout, is that the transistor base is receiving induced noise, which could cause undesired (...)

## Amplifier biasing: Methodology?

Hi, I´m working with Virtuoso/Spectre in the design of a low noise amplifier. The very first thing to choose is a proper transistor operating point which provides a good compromise between noise figure (low current) and high gain (high current). I´ve been told that the first thing is to define the (...)

## TIP35C as Pass Transistor Thermal Loss 50%

Linear regulators have low noise but poor efficiency unless Vdrop is held to a minimum. 50% is normal. when input is twice adjusted output. You mention SMPS design but this is not SMPS , which can do 80~90 efficiency. This is a LINEAR regulator. 1st define your acceptable requirements for input and output power, voltage, current

## Relation between Current and Noise (Input or Output referred)

The output thermal current noise increases with the current, but the transistor transconductance also. Then, you calculate the input noise dividing by gm^2, thus the input noise decrases. Consider the MOS thermal noise: SIDout = 8/3 kT gm = 8/3 kT 2ID/(VGS-VTH) and SVin = (...)

## why & how in most of the new applications, FETs are used than BJTs ?

FET is a voltage controlled device and so it doesnt need a high current to drive it where as the power transistor will have very less current gain so its base should be drived with the high current driver, another advantage of FET over BJT is very high input impedance,less thermal dependent noise,etc.., if (...)

## phase noise calculation

hi all, I'm designing a vco with its frquency ranging between 350-550MHz and for doing noise analysis i assume that the maximum phase noise in the circuit will be -120dBc and would like to know how could i find the current required for the shift mentioned above if the width and length of the transistor is known. Please (...)

## Circuit of BC817 as a switching transistor

Most probably your multimreter is drawing a few microamps which causes the leakage current on the amber LEDs Plus noise on the leads. noise (mains hum etc. throug power supply connected to mains ) rectified through LEDs. High impedence voltmeter and small leakage through LEDs makes two resisters in series potential divider circuit

## A problem of my LCVCO phase noise

I have designed a 5GHz LCVCO. when i simulate the phase noise of it, i find the phase noise is bad. Seen from the noise summary, the mainly contribute to the noise is the transistor from bandgap. The bandgap only generate a reference voltage, and convert to bias current for the VCO. When i (...)

## How to design the transistor size in this latch?

Review this book: Model and Design of Bipolar and MOS current-Mode Logic

## Noise or voltage triggered relay

I drew circuit for you, if someone will practice and count component values in circuit. If relay coil current > 100mA , add transistor to drive relay coil. 56089 Regards KAK

## difference between single ended ring and current starved ring oscillator

can anybody tell me difference between single ended cmos ring and differential CMOS ring oscillator?? what is the role of nmos and pmos tail transistor i n current starved ring oscillator?? which one is better between the two? and which one gives better phase noise peformance?

## Help on biasing transistor

the current in MN1 & the resistor R2 will decide the operating point of MN2

## Unwanted spikes on inverting converter output

I haven't found the cause of the unwanted spike: maybe a bad grounding layout, maybe radiated noise from the inductor. I would rather expect the diode reverse recovery behaviour as the main interference source. The commutating current path is usually through output capacitor, output diode, switch transistor and input capacitor. Unsu

## How can I improve the gain of CMOS Gilbert cell mixer?

In CMOS amplifiers reducing current generally improves gain. Perhaps the 2 bottom transistor's should be in Sub-Threshold. This also improves gain. Increase the upper transistor's L (length). This increases channel modulation effect, thus increasing incremental resistance Ro which will increase your gain. If you can't change W/L ratio (...)

## Is noise analysis necessary for all analog IC designs?

noise is quite critical, it depends on the application of your circuits, depends on what you are doing power relates with voltage through current offset can be reduced by larger transistor size, flicker noise is smaller for larger transistor size. noise is not important for some (...)