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52 Threads found on edaboard.com: Measure Differential Voltage Gain
For fully-differential AMP, I want to measure some of the most important paramters such as differential voltage gain, input impedance, output impedance. I have tried two method: one is to measure 4 port Scatter-paramter using network analyzer, and i got .s4p file and Sdd21. And in order to (...)
Mishu, If the input of the panel meter is always exactly 1V (i.e. it's constant), - Nick That was an example... i mean if it is 10mV, it have to be amplified to exact 1V. Thus if 20mV, then 2V. Actuallyi will measure small differential voltage across a shunt. (mostly for current sense...) To FVM=> The TI INA128 may no
i want to calculate/measure differential output and gain of a simple differential amplifier.i am using HSPICE and cosmos-scope.i have given +0.5v to one input and -0.5v to other input.i am varying the inputs,one from 0 to 1v and another from -1 to 0v.but i have doubt if it is correct or not.because both inputs should vary (...)
hello sir, i want to make a circuit that measure negative voltage of battery.i am using pic adc to measure this voltage, but does not read negative voltage. so i have convert this negative to positive voltage. problems 1. i don't have negative voltage on the system,to (...)
I want to design a one stage differential opamp to sense some on-chip low voltage signals. The opamp's differential gain is to be 10dB around, the bandwidth is about 1GHz. Can anybody give suggestions how to send the opamp's differential outputs off chip for measurement? What prober could (...)
We had some interference problems when we measure a motor supply voltage and some other voltages.We want to isolate motor voltage.What can we use to measure this voltage with isolation?
how to measure the offset of fully differential amplifier. any test bench doc or pdf available would be appreciable. regards
measure U1 with one pin, then measure U2 with another pin and perform calculation in PIC: U1 - U2 or U2-U1, dependig which way do you want/need it .. IanP :D
i think just do DC, and take the derivative of the output. BTW: why don't you measure the peak-to-peak swing instead of the gain? you can also plot the swing versus time.
Assuming that you are referring to a DC current you can use a resistor so that the current creates a voltage drop and use the ADC to measure that voltage. If the resistor is too low and the voltage is not high enough to be measured accuratelly then you can use a differential amplifier (...)
In the absence of a full schematic, the 4284 block diagram is still interesting in several regards: - it clarifies, that the differential measurement is implemented with rather asymmetrical impedances. This doesn't particularly suggest regular instrumentation amplifier topology - the low sense channel is actually implemented as a transimpedance a
I think you need to measure it. if you use simulate soft,you can find precise offset voltage.op offset voltage is not const value.
i am desinging the folded cascode differential opamp. for sample and hold amplifier. my supply is 0 - 5v. my input range is 2Vpp. my output range is also 2Vpp(peak to peak) my question is how to measure the output swing ( which should be 2Vpp) meand in which configuration i put my opamp.and what the input signal should apply at the input, so th
hi i am desinging the folded cascode diff output opamp with gain boost. how i measure the output common mode range of differential output . in books the output common mode range of single ended output opamp is given . plz tell the measurement of o/p common mode range of diff output. waiting for ur reply... manish
Dear all: I have designed a fully differential OP. However, I have no idea to measure it on real chip. I want to measue the open-loop gain. How should I do? Thanks a lot. Best Regards, slchen The open Loop gain will be infinity (however in the real world the max. outout voltage will a little (...)
hi all i am desinging the fully differential opamp with cmfb loop. how i measure the loop stability of cmfb loop. and for loop to be stable what should the criteria of gain and phase margin of loop. my supply voltage is 0-5 volt and common output voltage is 2.5 volt. regrrrds manish
Mark, An IA is a combination of 2 or 3 op-amps. It is differential in that there are 2 inputs to the IA, (call them V1 and V2). The output of the IA is equal to some amplification of the difference between the input signals, that is Vout=A*(V1-V2). The advantage of the IA is that it gives you a high input impedance, good common mode noise reje
Put 0.5 VAC to the in+ and -0.5 VAC to in-. measure the output voltage as out+ - out-.
Pls refer to Philip Allen's CMOS Circuit Design. He have explained in detail on doing the CMRR measurement.
Hi~~~~ If i have a single ended opamp, i want to simulation it offset voltage. I often see the simulation step is that Vin+ & Vin- tied to ground and measure output voltage, the output voltage/gain is the Vos. But when input of opamp is NMOS transistor and single voltage supply, it can?t (...)
Hi, I got this circuit from an IEEE paper. It says that the differential voltage signal at the input is detected by schmitt trigger M1-M6 which ensures a 25mV/50mV hysteresis. I know what schmitt triggering is, but my question is, how does this circuit able to perform schmitt triggering action? and how am I going to measure its hysteresis in (...)
Hi, i need to measure current in circuit with a 3.3V microcontroller(pic24 series). My question is: what op amp have I to use. Now I'm using LM358, but the simulation in TINA-TI shows, that max output voltage from OA is les than 2 V. And what should i prefer: differential ampl (high side measurment), or low side (...)
Hi, You can use a resistor to act as a "shunt". measure the voltage (potential difference) across the resistance. This can be used to detect the amount of current flowing: V=IR, so, I = V/R measure the voltage drop using ADC and convert this to current measurement in your code. Compare the read value (...)
Hi all. can someone help me how to find gain of an differential amplifier in cadence.. i mean what are going to be my virtuso parameters.. and how to plot graph, and how to measure gain ?? thanks, sreel
Sheet 3 of the MXP2010 datasheet shows it has a differential output voltage. I'm guessing that you using the LM741 as a single-ended amplifier, and simply grounded the Vout- pin? If so, that may have been part of your problem. Try using a differential amplifier configuration (has V- and V+ input nodes). Also, notice that the output (...)
Hello. I am using an external ADC (MCP3421), 16-bit resolution, with internal PGA (internal gain) of 8x to read signals from a thermocouple type T. Within my current ADC configuration, the differential input impedance is around 280K. But when the inputs are floating, the result of ADC conversions behaves incorrectly (negative and positive aleator
I was thinking about a single source, but I agree, that a differential excitation is better to measure excatly differential loop gain. In any case, the voltage source(s) have to be series connected, not parallel connected. With the unidirectional point, I was referring to the fact, that the loop (...)
The shown differential amplifiers have a gain of 1, that means the differential voltage magnitude is kept. I don't know how you are measuring input voltage, you should measure the differential voltage. I don't see however, how how you would get a (...)
Hi all, this is my result from simulation full differential folded cascode op-amp. how can i measure phase margin ? from v(out+),v(out-) or v(out+,out-)? I don't know why gain out+ or out- is less than (out+,out-)? How can I cansel offset foldedcascode(input transistors are pmos)?
Alternatively, you could try putting the resistor in series with the battery negative side. As long as you are careful with the sense wire placement, you should be able to measure the voltage drop relative to ground. Brian.
What about that
Greetings Reader, I am simulating an amplifier (A simple one) The amp is merely a differential pair with a tail current source and resistive load. differential Input differential output. I placed 2 ports at the Gates of the Pair - each of them having first and second sinusoid amplitude set to pin in dBm and swept pin in a swept PSS (...)
The schematics are hiding the critical point which determines measurement accuracy, a clear 4-wire connection of the shunt. To reflect the problem in the schematic, you should add wiring resistance elements. Then the amplifier input connection can be corrected to remove the wiring resistance effect.
What are the ways to reduce noise on the speaker? I have white noise from my speaker from otuput of the codec, even outputting zero. My setup: DAC---> differential output --> 10X power amplifier(bridged connection). From some measurement, I found the noise from the DAC is higher than the ground even though it outputs 0. Also,
Normally you should run pressure transducer of +V (in your case 24Vdc) and inside your PLC you will find 250 ohm termination resistor which is used for 1(4mA)-5(20mA)V range and that is typical configuration. If you want to run it of 0V check if your plc has differential inputs. If it has check in specification what is max common voltage for these
Hi. I think, .Tran analysis should be used for output swing calculation. you can use a .measure statement to measure p-p swing. e.g. .meas tran swing PP v(out) from=0.1ms to=0.2ms where in this case 0.1ms is the period of input voltage. But don't forget, you must calculate THD at least by using .four statement. having THD more than 2 or (...)
You are you simulating this circuit in open-loop, aren't you ? you must do it in closed-loop (i.e. with the feeddback network). Imagine that this circuit has a (open-loop) gain of 1000 and that the input referred offset voltage is 10 mV -> then the output voltage (with the inputs short-circuited) would have to be 10 V. As this is larger (...)
As your circuit is characterized by voltage (and not power) gain, be sure you appy and measure correct sources and loads. A common practice is to talk about equivalent power levels. for example you can express the input voltage as equivalent power to 50 Ohm load. To do so, take the 50 Ohm source and connect to 50 Ohm (...)
With +/-12V supply try to connect both inputs through (1kΩ) resistors to 0V and measure voltage on input pins .. Also, do you have any input protection in place? Regards, IanP
You can check opamp's power and measure 50 Hz on it (though opamp PSRR is high at 50 Hz ). But it could also be due to amplifier impedance is too high and some input circuitry exposed to surrounding electromagnetic field (e.g. ECG). You can do shield or filtering or change PCB layout or change to differential mode connection or ... But you
Try to vary the controlled voltage and measure the output frequency of VCO to see if the gain of VCO is met. If not, adjust the sizes of delay cells of the VCO.
What do you mean test: 1. Simulate amplifier which you design? 2. measure real device?
Hi Guys, I am designing an differential OPAMP in Cadence and would like to know if there are any tutorials that show how to measure the performance (different dc and ac parameters like gain, offset voltage, offset, bandwidth, distortion, etc.) of the OPAMP in Spectre? Thanks.
almost any circuit simulator can do that, it is called AC analysis, you select an ac source in the input of a circuit and measure the frequency response (gain/frequency graph). Multisim can do that , instead on doing an interactive simulation you have to open the simulate menu and you will find a sub-menu (analysis) in which you can find many ty
Connect it as unit-gain feedback buffer to measure input offset.
What you are describing sounds like too narrow an input common mode range, choose a point within your target input range outside the gain spike and make sure all your devices are in their intended region of operation (probably saturation for all of them) at that OP Another possibility is that the systematic offset is altering the simulation result
I'm sorry for the late answer. I seem to lack the knowledge required to analyze the Limiting Amplifier deeply. I am sorry. But something is wrong about your simulation results. Your inputs are 120 mV and the sources of the input MOSFETs are -0.7 V (If your input must accept common mode range of 120 mV you might want to use the PMOS equivalent of
Common Mode Rejection Ratio. A common mode voltage is one that is presented simultaneously to both inverting and noninverting inputs. In an ideal opamp, the output signal due to the common mode input voltage is zero, but it is nonzero in a practical device. The common mode rejection ratio (CMRR) is the measure of the device's ability to (...)
Putting some emphasis on correct technical terms, we should talk about temperature drift as in (a systematical effect) as in the question title in contrast to random fluctuations. In the present circuit, resistor T.C. can be expected to be the most severe drift source, at least factor 10 larger than OP offset drift. It's promoted by a unsuitable
Hi!, We have just designed a 2 stage OTA with a cascoded differential pair as the first stage and a common source amplifier as the second stage. The gain is 59.3dB and we need to measure the slew rate. Can anyone please tell me how to go about measuring the slew rate? The method that we were using is to supply a 1Vpp pulse at the input (...)