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99 Threads found on Active Biasing
active biasing is often used in rf power amplifiers where emitter or source is grounded. Such amplifiers are usually dissipating heat. To improve temperature stability negative dc feedback is used to keep average collector (drain) current constant. Feedback is usually made with PNP transistor.
HI, I am interested in a LNA design for low noise. I am told to use an active biasing to minimise the noise figure and also have a lower VSWR ratio. Does anyone have idea what is active biasing and where can I find information on it? Thanks for the help Rula
HI, I am interested in a LNA design using BJT for low noise. I am told to use an active biasing to minimise the noise figure and also have a lower VSWR ratio. Does anyone have idea what is active biasing and where can I find information on it? Thanks for the help Rula
Hi, everyone. I have a question about what kind of op-amp I should use to design an active biasing for a power transistor. Basically the I am going to employ a sensing resistor to capture the power supply current from Vcc to transistor. The voltage drop is then compared with a reference voltage by an op-amp. And the op-amp output is connected to
Im checking out this FET type LNA IC (ATF-54143) that offers two different schemes of implementation (passive biasing and active biasing) What is the difference between the two? Is one scheme better than another in terms of providing gain, rf output?
Hello, Did you have a look in their web page (Minicircuits) or the data sheets. If you are talking about a Minicircuit active mixer the power is required for the internal amplifier module so current consumption will depend on the model. Passive mixers don't require any biasing. Cross
There is an IC from infineon for an active bias circuit. i am not sure that you can use -0.2 v or not.
try active bias circuit, it is more stable voltage for temperature change.
Suppose in your second stage you have NMOS common-source amp and PMOS current source load. Then your second stage biasing current is mainly controlled by the PMOS current source, and actually Vgs of the NMOS is determined by this current. However if the opamp is used as a feedback amplifier, the common-mode feedback will automatically adjust the Vg
Appcad has the capability you need. Go active Circuits, scroll down twice, or more, and you will find the bias calculator you need. g579
i need a famous topolgy for designing an active bias network for an LNA operating at 11.5 Ghz in an LNB .. i found a one in Gonzales book but i need a good application note about this topology... Another question....will the noise figure be degraded so much after biasing the transistor with this topolgy ?! THANKS IN ADVANCE..
walters, Why do you have to set Baising for a Tube or transistors? biasing is required for any transistor that is designed to function as an amplifier, not a switch. biasing sets the DC operating conditions, operating region of amplification and AC swing. What is the Operating Stage for a Tube? I don't quite
4th edition of Gray and Meyer teaches you basic to advanced biasing circuits. See active current mirrors chapter. I guess, it is chap.4. Hope this helps.
bias 1. Any parameter of which the value is set to a predetermined level to establish a threshold or operating point. Although it is common to think of bias currents and bias voltages, other parameters (e.g., capacitance, resistance, illumination, magnetic intensity, etc.) can serve as biases. 2. In a high-fidelity audio system, a circuit in
emavil, In addition to the good advice from kevpat, here a couple of additional considerations: . Look at the spec of the output driver that is used to drive the transistor. If the driver has a passive pullup resistor, then there is no prblem with using as low a value resistor as you want. Keep in mind, however, that the passive pullup resisto
hi knack, In electronics every active device, ex. transistors, needs a contant dc current and voltage on it to work properly. Setting this current and voltage level and giving it to the device is called biasing. biasing determines a device's operating point. What i meant by operating point is: for ex. by bias level you can change an (...)
hi all, wanna know the difference between active and passive mixers (like how the gate n drain biasing will be in both) n which one is better??
Can anyone show me how to setup the simulation in AWR for a BJT frequency multiplier? I am using an active biasing network also. Thank you, ks
Hi One of the reasons I am interested about this, is regarding active biasing. I have found some articles, that say that active bias can be difficult to achieved with class AB amplifiers. I have attached a paragraph from an article discussing this. I have seen different ways to do active bias. One is where we use a (...)
Hello! I´d like to design a limiter with pin diodes. When I use two pin diodes (without active biasing) the point at which limitation starts is to low. The limitation begins at 5dbm - I need it at 30 dbm. How can I solve the problem? Any usefully documents? nice greeting :)
I m studying basic filter circuit.Was given a task to modify a passive bandpass filter to an active op amp bandpass filter,the passive filter spec is given below: Low pass filter - R(68 ohm), C(0.047u F) , fc=49.8kHz High pass filter - R(3.3k ohm), c(0.047u F) , fc=1.03kHz anyone can teach me how to convert it ?Thx.
active Frequency multiplier would have been more appropriate topic for this query. As multiplier in analog electronics means mixer . Can anybody explain in case of HEMT/MESFET which are biased deep in nonlinear region(for multiplier action), how the bias point shifts(or vary) as the circuit experience extreme cold and hot temperatures ? As
Hi, In reference to u r ckt, M12 and m13 act as pre charge devices which pull either of out- or out+ to vdd (its explained how this happens in CS amp with diode/active load in razavi) If you use a resistor to do this job, there will b a drop across it so u r output can't reach vdd any time. which is not the case when u use a pmos device.
Hello, can anybody help me? I design pulsed power amplifier and I need help with biasing TIM8596-15. How can I do temperature compensated active gate bias and how can I set right drain current? Pulse width is 300ns-30us, D.C. max 20% and PRF 3-50kHz Thank you
I suggest taking into account all the parasitics you get from components, including PCB layout. The SRF of the capacitors is the first thing you have to take in consideration at this frequency. For example a 5.6pF 0603 capacitor have the SRF at 2.45GHz, which can give you a lot of headache placing it in a matching network. Ideally is to
Hello, You can do this biasing very easy & simple just use the BIASTEE elemet available in Microwave Office (MWO) (Elements => General => Passive => Other => BIASTEE) Which is just Ideal Bias Tee & which does not affect the input admittence... See the attached picture for the setup for your active Capacitance circuit DC biasing...
hiii.... I used ac simulation to find my inductance and Q factor..I will recheck the s-p analysis later. There is another problem....I implemented a cascode active is meeting my specs....Now i have to implement tunability...What do you suggest is d best way...i'm thinking of changing the bias my g
For the most basic single ended differential input amplifier with one current source and two active load, both the current source (MOSFET) and active loads (also MOSFET) are required to be biased for expected dc current as I see in text books. Say for example, the current source is to be designed to sink 20uA and the active loads will have (...)
Your bias current changes with the supply voltage, this explains why you see a bigger variation with power supply. You should bias your active device with a current source to keep the bias current constant.
Hello, I'm building a frequency synthesiser using a national semi's PLL. Because, the VCO's tuning voltage is out of the range of PLL power supply. I choose to use a type A active filter as attachment. 52508 I used National semi's easyPLL to get a loop filter with 3order, and test it in real circuit. I found the volta
Hi I was searching if a transistor is linear device or not. A linear device has a linear relationship between current and voltage (Ohm's law). I'm a beginner in this electricity and electronic stuff. So, please keep your reply simple. Thanks. While searching I found this: We will operate transistor mainly in 4 regions, namely
I'll conjecture a guess. active gain probably refers to transistor base current flow. (The transistor is the active component in this circuit.) Base current finds a path to ground via one of the coils. Don't break the lines carrying this current. The feedback loop is the network that particularly creates the oscillations. You don't want t
In general, you should not rely on MOSFETs matching well, unless you've binned them so they match. In a single production run, the MOSFETs will usually match okay; they might differ only by 50mV or so. However, if you obtain two MOSFETs from two different production runs, they might be 200mV off from each other. A difference this large would probab
Hello biasing the transistor meaning setting it in the right position of the amplifier operation region. in bipolar transistor amplifier the bipolar transistor has to be in the active region and is done from the DC setting which nothing but the biasing. the exact point of the setting is the Q point, in order to have maximum amplification we (...)
Offset is important in all applications where the DC level plays a role. Also remember that you have two offset components: systematic and random. Systematic offset arises for imperfections in your design. Random offset is given by the random mismatch appearing among devices "supposed" to be equal. Reducing systematic offset depends upon y
Hi, I got a differential input (actualy it is the input of active mixer IC), they gave the differential S11. HOw can I match that input? I do need a transformer to a single end but I have no idea how to do the matching. Also, any tutorial on dfferential input will be very appreciated.
urs question is not clear..anyway i think its possible to bias both active and passive devices...any way xplain Q clearly........
Inverter circuits can be used as an amplifier, and they usually be configured as Class-AB amplifier (or Class-B, depends on biasing conditions) since both PMOS and NMOS receive driving force from the inputs. However, Class-AB circuits are difficults to bias than the traditional Class-A circuits, since a floating constant voltage source must be pres
Sorry the jpg vanish! I rember there was indeed an active load. Added after 6 minutes: The jpg load time was more than 120s The 40kOhm resistor is for biasing the current. You can use instead a circuit similar to a PTAT but with a NMOS (PMOS) biased at two NMOS (PMOS) diode voltages used as resistor.
Hi, I surely have checked the bias conditions, they're definitely in the active regions. I apprecitate if you have a shot at this circuit with SP simulation. Thank you.
The simulation result of an amplifier is different from the result that I calculated by formula. I design an amplifier. Using spectre simulator, the gain is more than 80dB. But using the formula Av=Gm*(Ro||Rl), I can not get the same result. It is much less than the simulation result. I get the parameter from the DC operating point of spectre. T
Hi! I am new to this forum. My question is, does anyone have an idea of a good test-bench for simulating the Common-Source Amplifier? I mean, how to bias the active transistor(dc voltage at the gate) such that the output is maintained at a particular value, for instance (vdd+vss)/2. The biasing scheme need not be practical. Its just for the sa
Changing the input Commom Mode voltage at the input will not affect the biasing of later stages. So the transistors at the later stages should still work in the active region. hi all, i have a doubt on icms. with regard to that, we normally calculate the min and max swing by considering the conditions for the transistors in the input
hi i want to design wideband rf splitter and amplifier(active splitter) any one have a schematic or pcb using minicircuit device?
In your 1st stage differential amplifier, if you are using an active current mirror load then you can define the drain voltages (the Common Mode Output voltage) as Vdd - Vgsp (Vgs of the PMOS transistor). If things don't seem to be workin gin Cadence it may be that you may be putting the input biasing wrong, or you may have the wrong parame
i think the expected s parameters will be like loss passfilter , coz the radial stub acts as shut capacitor to ground , and the high impedance line act as inductance "RFC" this structure is always used to feed the DC voltage to the active device and eleminate any RF signal from pentrating to DC circuit , which this help khouly
Oscillator Design and Computer Simulation Randall W. Rhea This book covers the design of L-C, transmission line, quartz crystal and SAW oscillators. The unified approach presented can be used with a wide range of active devices and resonator types. Valuable to experienced engineers and those new to oscillator design. Topics include: limiting
i found it used for self-biasing at source of fet(filtronic application documents) for designing broadband mpa or lna. the active device is (p)hemt chip. please give some detail information about it,good luck!
M55 & M56 only carry small amount of current. They are not active transistors, so they don't involve in ac analysis. I guess these two transistors just provide enough biasing current for the M13 & M14 to increase the gm of (M13 & M14). More system information are required (e.g. your circuit application, types of signal your circuit are required to
hi there are many methods to biase a transistor that is to put in the active region to work as a linear device rather than aswitch regards