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155 Threads found on edaboard.com: Differential Mode Output
i would like to know the factors that limit the amplifier common mode input range and the output range? if both ac input are zero why the common mode gain is not zero?
1-If you use two I/Q Mixers, it will be easy to seperate wanted and unwanted sidebands at the output.You can use a polyphase filter to discriminate them.. 2-Yes, 90 degree phase shift is necessary to drive I/Q mixer combination.. 3-Yes, differential structures have theoritically no even mode harmonics.
Short the inputs together and apply a sinewave at the input. Measure the output. The ratio out/in is your common-mode gain. The ratio between the differential gain and the common-mode gain is your CMRR.
Loop current ought to result in differential mode noise, but not all current returns, some goes out the output, and the imbalance might appear to have some common mode component. To the extent that AC ground current and input current are in phase (likelier during edges than the quasi-DC settled conduction periods) the (...)
I have designed balun-LNA using parallel combination of CS and CG stage. My circuit has differential output and single ended input. I matched the input for 50ohms since it is single ended. But my doubt is how to match the differential output for 100ohms. For output impedance matching, i have separately (...)
ib1 = ib2 -> Vo1 = Vo2 -> Vo = 0 -> Ac = 0 Where am i mistaken? For common mode gain, you should calculate common mode output voltage Vo = Vo1 = Vo2, respectively Vo = (Vo1+Vo2)/2, not differential output voltage.
i am simulating a differential pair in CADENCE and having problems regarding the mid rail biasing and clipping . my amplifying pair is constantly biased at a voltage much higher than the mid range. Any suggestion regarding how can i ensure mid range biasing of my mos amplifying pair without effecting my gain, BW and other product values?
I am doing the project on Modified Nauta configuration using double CMOS pair. Plz help me how to calculate slew rate, PSRR, "dc tran ac" for gain, CMRR. And plz tell me the mathematical analysis for this configuration to above parameters and differential output transconductance and common mode output transconductance.
CM = Common mode DM = differential mode vimalkhanna are you sure the interference is leaving on the DC wires alone and not between the AC and DC wires. Low frequency interference is often radiated with the source in the middle of a dipole formed from both input and output wires. Brian.
Dear All, I need to design a simple single-ended differential input pair OTA for gm-C filter. Here the Gm-block should operate in open-loop configuration. So if there is no negative dc feedback how can I ensure the output common-mode level. To provide only DC-feedback, I need to use large resistor and large capacitor which is not (...)
Usually you would need more specs like what is the supply voltage minimum and what is your process threshold voltage. Should the compensation be internal or should the output pole be dominant (if it drives capacitive loads). Input common mode range? output swing? differential or single ended output? (...)
Hi, The output voltage of a simple differential opamp amplifier is being said as Vo=Ad(Vb-Va)+Ac(Vb+Va)/2 We can definetly derive the differential mode gain using super position theorem. But can somebody tell me how the common mode input signal is taken as (Vb+Va)/2?? Is it simply taken as the average (...)
Hi, Im trying to do a ac analysis of a opamp differential amplifier the circuit is shown below. The input is fed with a common mode ac signal 1 vpp. The differential stage is given a 6V offset too.. So for the common mode signal the output ideally will be 6V dc signal only.But when i do the AC analysis (...)
Hi, May be this is a stupid question,.. but i ve got a doubt with CMRR of an amplifier.. I came to read an equation saying CMRR is defined for an amplifier as CMRR(dB)=20log((Gain*Vcm)/Vout) gain = (differential) gain of amplifier ;VCM = common mode voltage present at the input VOUT = output voltage resulting from (...)
Hi, May be this is a stupid question,.. but i ve got a doubt with CMRR of an amplifier.. I came to read an equation saying CMRR is defined for an amplifier as CMRR(dB)=20log((Gain*Vcm)/Vout) gain = (differential) gain of amplifier ;VCM = common mode voltage present at the input VOUT = output voltage resulting from the presence of (...)
Which offset: input, output or inout offset? Schematic or extracted layout dataBase? Note: from a symmetrical differential input schematic, you won't find any input offset. output and inout offset is common mode voltage dependent. For such dependency, use DC analysis and sweep an additional DC offset voltage between the (...)
I have a question about the input bias for a fully differential amplifier. As showed in attached file. 52186 There I have a single-ended input signal at the port Vin+, how can I creat the DC bias for another input Vin- from the positive output? Thank you!
Dear all, A common mode feedback circuit takes the output of the differential circuit as inputs, averages them and finally subtract them from the "common mode reference voltage" to yeild the desired output which is supposed to be fed into the main differential amplifier. Can anyone tell (...)
Dear All, I was wondering if there is a way to increase the head room (common mode voltage) in a simple diff pair My VDD is 1.2 V and the drain resistors tied up to VDD are 50 Ohms the output swing should be 1V diferentially, requiring something like 20mA(Depends if in DC or AC mode) as DC current sink Any suggestion is welcomed (...)
I expect any decent fully differential amplifier, will have a common-mode reference and common-mode feedback circuit. Your dc offset voltage is still the input difference at output null (difference). I prefer to use controlled sources with a ground referred output to pick off the quantities dvi and (...)