37 Threads found on edaboard.com: Cascade Amplifiers
I need to cascade amplifiers to achieve higher gain. But my signal output from first stage includes a DC offset. How can i remove the offset without using a coupling capacitor between the two amplifiers.
Please also let me know of any notes/tips on cascading amplifiers.
Thanks in advance
Analog Circuit Design :: 21.09.2008 04:43 :: awan :: Replies: 1 :: Views: 827
After added feedback oscillator it started to oscillate. I don't want it.
First comment, you don't necessarily need to cascade amplifiers, because the shunt has the same ground reference as the input signal. But with sufficient fast OPs, you possibly get stability problems due to the MOSFET input capacitance even with a single OP.
Analog Circuit Design :: 01.06.2011 10:21 :: FvM :: Replies: 17 :: Views: 1049
This is quite wideband and cascade connections may not give this bandwidth and power level. Instead of that, "distributed amplifier configuration" should be used. For this kind of amplifiers, there are lots of document and paper. But it's quite difficult to implement.
RF, Microwave, Antennas and Optics :: 28.05.2004 13:34 :: BigBoss :: Replies: 4 :: Views: 1711
There are monographs with filter order coeficients people have calculated them from decades ago. It simplifies task of determing component values.
"On the Theory of Filter amplifiers," Wireless Engineer, vol. 7, 1930, pp. 536-541 by Stephen Butterworth (hence the name!)
"cascade amplifiers with Maximal Flatness," RCA Review, vol. 5, (...)
Analog Circuit Design :: 17.09.2004 09:35 :: djalli :: Replies: 13 :: Views: 2841
cascade connection means that two or more stages are connected together in a way that output of previous stage is connected to input of next stage and so on.
Electronic Elementary Questions :: 04.09.2004 05:55 :: Borber :: Replies: 10 :: Views: 7358
Hi everyone. Need some advice from you all. Basically when we cascade amplifiers we faced the problem of bandwidth shrinkage. Is there any way where i can resolve or at least reduce the bandwidth shrinkage.
From the text books for example Franco and such we can find numerous formulas to have the widest bandwidth however this is not a transistor
Analog IC Design and Layout :: 05.09.2004 01:28 :: chinboon :: Replies: 1 :: Views: 1217
What everyone described is a cascode circuit. cascade connection is a similar circuit but with a signal decoupling at the connection of the two stages, so that it is connected as in cascode for the DC current only (to get higher efficiency by using the same DC current for both stages), but still get two independent stages for the AC signal.
Analog Circuit Design :: 26.04.2005 00:47 :: strabush :: Replies: 5 :: Views: 5373
I have a question on the mixed signal circuit. We are designing a 155M limiting amplifier which consists of the cascade of amplifiers and an output buffer.We treat the cascade amplifiers as analog part and the output buffer as digital part because it works like a current switch. To isolate the crosstalk from the output (...)
Analog IC Design and Layout :: 21.12.2005 00:26 :: John Xu :: Replies: 4 :: Views: 1610
if there are n stages of amplification each with bandwidth = b what is the effective b.w of all n amplifiers in cascade?........
i found it as b.(2^1/n -1 )^.5......how?
Electronic Elementary Questions :: 21.01.2006 22:42 :: abishek :: Replies: 1 :: Views: 4398
very oftenly i was messed up by this question....how to find the differences between Cascode and cascade amplifier... LIST out some prons and cons of cascade and Cascode amplifier
Electronic Elementary Questions :: 10.02.2006 08:38 :: electronics_kumar :: Replies: 5 :: Views: 11744
Liang,J.Y.,and C.S.Aitchison,"Gain Performance of cascade of Single Stage Distributed amplifiers," Electronics LEtters,Vol.31,NO.15,JUly 1995,pp1260-1261
Banyamin,B.,and M.Berwick,"The Gain Advantages of Four cascaded Single Stage Distributed Amplifier Configurations," Digest of the iee
RF, Microwave, Antennas and Optics :: 20.08.2006 02:12 :: raghavenderece :: Replies: 4 :: Views: 861
The transistor doesn't have a voltage gain,it has a transconductance i.e it varies its current according to the applied voltage .OpAmps are voltage amplifiers that may be of cascaded single stage amplifiers .When you cascade amplifiers, the total gain will be the multiplication of the gains of all (...)
Electronic Elementary Questions :: 01.06.2007 15:40 :: ieropsaltic :: Replies: 7 :: Views: 5104
Hello, before I ask you my question I just wanted to say I am new at the board.
So over to my question. I need some help to dimension a cascade circuit amplifier with the LM324. The circuit must fulfil the following values:
- In Impedance = 25kΩ
- Above frequency = 100Hz
- Below frequency = 150kHz
- Maximun gain = 40dB
I have solve
Analog Circuit Design :: 07.10.2007 08:06 :: Ventilo :: Replies: 2 :: Views: 708
Everytime when I try to plot the noise figure from a cascade using standard s-parameters files involving amplifiers and filters in between I get a warning message in the microwave office (or similar like Genesys) saying that for example the filters does not contains noise parameters, so therefore the device will be treated as noiseless.
RF, Microwave, Antennas and Optics :: 06.05.2009 10:46 :: enrico :: Replies: 5 :: Views: 1515
one year ago, I made that project,
I used two OP. I have found resistance values for cascade amplifiers
The first circuit had 10 of gain, then there were a filter and finally the second amplifier (100).
The cascade configuration avoid noise between stages.
Microcontrollers :: 02.07.2009 13:27 :: alberto1683 :: Replies: 4 :: Views: 1200
When i verify the cascaded amplifiers with ADS S-parameter simulation, i get a nice curve showing that i obtain 60 dB gain at the IF frequency, which is what i want.
However, for real implementations 60 dB of gain can become a problem if the amplifier is not band-limited, i.e. by having filters in between cascaded stages. I dont undertand (...)
RF, Microwave, Antennas and Optics :: 03.05.2010 11:44 :: Xavipersonal :: Replies: 4 :: Views: 794
I was searching the net for this topic but it's hard to find...
I have a sine signal obtained by an active opamp filter from a square wave.
This opamp has single supply, and so the reference for input and output signals is Vcc/2.
But if I have to add a second amplifier stage (another opamp), how can I connect it to the output of the
Electronic Elementary Questions :: 30.04.2011 11:41 :: vaka85 :: Replies: 16 :: Views: 1822
I am constructing an RF Chain. I have put 4 amplifiers in cascade. I have added a tone source. The P1dB and IP3 are fixed. So, I can vary only the gain(transducer gain). The cascaded gain, I am getting 50dB but noise figure is showing 166dB. Certain times, i also get the message, no noise power is available at input. Should I add (...)
Electromagnetic Design and Simulation :: 21.09.2011 08:41 :: avins_1234 :: Replies: 0 :: Views: 861
You can connect two MiniCircuit amplifiers in cascade. S12 vill be the sum of them both. Use PI-type attenuators at input, between amp's and at output to achieve correct overall gain AND to serve for low input/output VSWR. Careful PCB layout is important to maintain S12 isolation.
RF, Microwave, Antennas and Optics :: 15.12.2004 18:11 :: VSWR :: Replies: 7 :: Views: 864
A 2 stage CMOS opamp is a operational amplifier which is made up of 2 amplifying stages in cascade. 2 stages are generally used to achieve high voltage gain and high output swing simultaneously, 1 stage is optimized for each parameter.
You can have more stages in cascade to acheieve higher gain, but at the expense of reduced bandwidth. See the
Electronic Elementary Questions :: 15.01.2005 06:57 :: aryajur :: Replies: 8 :: Views: 1571
Thanks for the reply. I have cascade of 3 identical stages. Persistence paid off. Though I had 1000pF decoupling caps on the drains and no spurious oscillations were visible, after adding a 10uF on drains the gain jump up to 30dB. The peak is still at the lower frequency, but at least I have a fighting chance now!
RF, Microwave, Antennas and Optics :: 22.02.2005 15:11 :: edf :: Replies: 4 :: Views: 997
For analog Design, the maximum frequency is a somewhat vague concept since you can increase your frequency of operation using distributed amplifiers. ft is the unity current gain frequency which can be found out using the expression:
ft = gm/(Cgs + Cgd)
but this has little meaning. A more meaningful frequency metric is the unity power gain
Analog IC Design and Layout :: 28.03.2005 07:07 :: aryajur :: Replies: 3 :: Views: 912
I want to design a power detector which can monitor the received signal power. I know one implementation is to use piece-wise linear proximation of the logarithm function by using a cascade of limiting amplifiers, which can be implemented with CMOS process.
If I don't want to use cascade of limiting amplifiers(which (...)
Analog Circuit Design :: 10.08.2005 05:28 :: John Xu :: Replies: 0 :: Views: 434
I need help concerning CATV specifications. I crossed upon the C/N ratio and it's use in CATV system design. C/N of and amplifier means the ratio of Carrier to the output noise of it. For one unit this definition is fine, but what about a cascade of amplifiers ?
In ordinary RF cascade design, one wants to calculate the (...)
RF, Microwave, Antennas and Optics :: 14.11.2005 04:45 :: eyalc :: Replies: 0 :: Views: 1067
I saw "cascoded" and "cascaded" in some books and papers
i am confused,who can tell me the differents about this two words?
thanks a lot!
Analog Circuit Design :: 16.12.2005 01:07 :: hanson_uestc :: Replies: 4 :: Views: 718
I have a doubt in the Book "Design of Analog CMOS Integrated Circuits" by Behzad Razavi
Chapter 8 Page 253 Figure 8.10
cascade of two 100 Mhz feedback apmlifiers able to provide faster response
as shown in the figure 8.10(Left) what will happen if we choose f 3db = 100Mhz for 20 Mhz amplifier.
Will the response of a single amplif
Analog IC Design and Layout :: 24.10.2006 02:54 :: Robinenemy :: Replies: 2 :: Views: 1217
Greetings, I recently posted a topic in the simulation board about stability calculations and smith chart plots. This is a relating question, but more general.
In my design that I'm trying to do some stability calculations on I have 3 (surface mount technology) LNAs in a cascade.
It looks approximately like this:
input --- LNA --- LNA --
Analog Circuit Design :: 27.11.2009 13:02 :: tjuby :: Replies: 0 :: Views: 538
The story of dimensioning the max bandwidth of an opamp is much easier if you start from the end.
The opamp could not have more bandwidth than the output stage. The Gm/Cload of the output stage define the parasitic pole which could not be compensated or avoided. If the phase of the ouput stage reach -30° the unity gain of the opamp and the feedb
Analog IC Design and Layout :: 18.12.2009 16:29 :: rfsystem :: Replies: 6 :: Views: 1502
A “cascode” amplifier uses a transconductance amplifier followed by a current buffer, when a “cascade” amplifier are two (or more) transconductance amplifiers following one to each other.
I found there are a lot of papers and books which are confusing these two terminologies.
RF, Microwave, Antennas and Optics :: 04.04.2010 00:34 :: vfone :: Replies: 2 :: Views: 1273
I have read a bit about transistor design for amplifiers, the parameters that are needed for stability and how to design for stability etc.
However, it seems that for the most part, stability considerations and tests such as Rollets K-factor and the mu-parameter are meant for a lone transistor and matching networks.
Now, I am not desi
RF, Microwave, Antennas and Optics :: 29.08.2010 09:34 :: tjuby :: Replies: 0 :: Views: 430
This is not a power amplifier. There are two low signal amplifiers placed in cascade. The low pass filter at the output has a cut-off at 75 MHz, and need to be re-designed to allow passing 95 MHz signal. (see the attached
Analog Circuit Design :: 17.12.2010 05:39 :: vfone :: Replies: 12 :: Views: 1085
You cant use 2 identical pre amp as cascade . because their out put impedance and input impedance can not match.
you should use 2 stage pre amplifier as cascade , with considerating out put and input inpedance. it is very simple with op amp. but if you want to use transistor , i suggest you common base pre amplifier because it
Analog Circuit Design :: 20.08.2011 11:03 :: goldsmith :: Replies: 1 :: Views: 771
I've just read in a book that a cascaded circuit has a high input and output resistance.
About this I have a two questions:
1) which advantages has a circuit with high input and output resistance?
2) why is a cascaded circuit useful for a circuits?
For every answer I will be thankful.
Analog Circuit Design :: 24.01.2012 04:28 :: Student1990 :: Replies: 5 :: Views: 213
I am trying to amplify a 30dB ENR noise source to +30dBm. For my initial stages I am using a MMIC darlington configuration amplifier with a gain of ~19dB (these are input and output internally matched to 50 ohms). I made two pc boards one with 3 stages (54 dB gain) and one with 2 stages (37 dB of gain), each work we
Analog Circuit Design :: 03.03.2012 19:34 :: enjunear :: Replies: 3 :: Views: 634
If there are two BJT small signal amplifiers (common Emitter) cascade connected using a suitable decoupling cap
The first preamp has an o/p imeadance Zo, and the second has an i/p impedance Zin
Now we have Zo and Zin and a cap betwwen them
My question is: Is the connection series or parallel? That, is the o/p voltage divided or the o/p curre
Analog Circuit Design :: 06.05.2012 03:59 :: samy555 :: Replies: 21 :: Views: 696
I have designed a white noise generator. the o/p is very low, so i used amplifiers to take the level upto mV. I also need to incorporate a dc level to the o/p. I used many circuits for this prupose, but no dc shifting. I tried simple voltage divider, opamp ( Non-inverting ac coupled) biasing etc etc, result is same : no biasing.
Here is the samp
Electronic Elementary Questions :: 13.06.2012 03:12 :: paawan :: Replies: 4 :: Views: 496
Ensure all of them are 50 ohm terminated so they can be cascaded, but as you cascade more the power increase and question here arises weather the transistor in the amplifier sustain that much high input??? e.g. your final or 10th stage amplifier in cascaded configuration will have 4500 W at its input !!!
RF, Microwave, Antennas and Optics :: 20.05.2013 01:57 :: Ow@i$ :: Replies: 4 :: Views: 421