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122 Threads found on Sample And Hold Circuit
I am designing an ADC in umc 65nm which operates at 1GHz. The analog section consists of the sample and hold and a bunch of comparators. The digital section consists of an Encoder(synthesized in Cadence Encounter). When I connect the analog section and digital section to different power rails(VDD_A (...)
The analog input impedance of the PIC is very high. The reason for the 10K "recommended" limit is because the pin goes through an analog switch matrix to route the pin to a sample and hold circuit. The S&H 'snapshots' the voltage so it can't change while the measurement is being taken. It uses a capacitor to (...)
I try to simulate a chopper instrumentation amplifier. Chopping frequency is 5 KHz and cut-off frequency is 700 Hz. I use pss+pnoise analysis to see the noise spectrum and measure the integrated noise, but it seem to be wrong. Is it necessary to put an ideal ?sample-and-hold? circuit in (...)
Perhaps you wish to catch the maximum readings? During every 1/50 sec? Or 1/10 sec? Or 1 sec? Then this might be a job for a sample-and-hold circuit. It depends on what amount of detail you wish the data to contain (for instance, waveform as jackhammer makes single break through concrete). Also depends on what timeframe (...)
Regarding sample-and-hold chips, I would simply assume that ICs like AD783 with sufficient speed aren't available in your country. Sorry for that. sample and hold circuits with OPs and separate analog switches are shown in many OP application (...)
Hi, I have a question about simulating the noise of a S/H circuit. The method I am using right now is to simulate noise in sample and hold phase separately. First, I put it in sample mode and simulate the noise over the sampling capacitor (CS) and (...)
Hi, you want to to store any anloge value? Then look for sample and hold circuits. But it keeps value only for a limited time... For inifinte time maybe digital pots are useful. It needs a comparator and some logic. It needs some sampling time for the wiper to adjust. then it has theoretically infinite (...)
Accoring to kT/C noise theory, I expect to noise power as much as 37.692nV2/Hz because of 100fF load capacitance. However, the simulation results shows just 0.3464fV2/Hz at flat zone (white noise by thermal) likeIntegrate regarding frequency. Then you can get same value for both static case(dc-noise) and sampled c
You need way, way better than 1MHz BW for that fast of a conversion rate. I'd suggest that you think of track/hold rather than sample/hold (the latter implying a shorter sample window to me, short window makes the settling time a greater problem). Depending on the loading of the "S/H" you might have a bare cap (...)
some PA systems will sense the ambient sound level and automatically adjust the volume so it is above the background sound level so you might look at the circuit blocks they use. I would surmiss it is a sample and hold circuit feeding a DC controlled voltage amp
Hey guys, I have a basic question about SC circuits. Say we want to have a switched cap circuit as a sample and hold in an ADC or as an integrator. If the resolution of the converter is expected to be 10 bits, I wonder if it means that the voltage stored on the capacitor should be within one LSB error of (...)
Hello all, I have a basic question, when we design a sample and hold or switch cap circuit, the output of the circuit (voltage on the sampling cap in SH, or on the integrating cap in integrator) would not be exactly like the input voltage. Now I am not quite sure about these issues: 1) which parameter (...)
Hi, I'm trying to design an two staged Op amp for a sample and hold ciruit with 125v/us slewrate and GBW>50 mhz with 60 degrees phase margin. My main problem is that i can t fullfill both gbw and phase margin requirement. Am i doing something wrong or should i just use a different amplifier? I (...)
What are the sample and hold circuit ..... What are it's specification..? One of the better thread and solution so far.
Hello, I'm designing a differential sample-and-hold. I have some specifications I have to met. The maximum supply voltage is 1.2V and there is chosen to be 100mV margins on the supply lines leaving a voltage swing of 1V from 0.1V to 1.1V. The kind of circuit I am designing is the differential equivalent (...)
Hi, can u please tell me how to draw sample and hold circuit in cadence using two stage opamps.....and can u please tell me if i give input voltage 1.8v the how the output voltage in sample and hold circuit..Can u send me the (...)
Hi all, during the simulation of the sample and hold circuit, i have encountered one problem. the circuit is a simple sample and hold circuit consisting of a switch and a capacitor. the input is vsin with pac mag set to 1. (...)
The falling edge of the pulse (that is used for reset of the integrator) can be used for storing its voltage into a sample-and-hold circuit, only if the new value is lower than the old. I.e., there is a comparator that enables or not the S&H. (There should be a small delay before the integrator reset.) Regards Z
Hi, i am Dev working for a project Flash ADC design using Tanner EDA, I am very much new to this tool and facing lot of problems with the design of FLASH ADC. Please help me how to start.I am want to design sample and hold circuit using CMOS 180nm Technology. Please help me how to start.
I am playing with sample+hold circuits in pspice and after getting frustrated with leakage currents across mosfet hold switch I went to falstad and tried to come up with a way to compensate for the leakage using ideal and identical components. Here is part of an sh (...)
The S/H (sample & hold) is a separate function that is part of the inputs of many (but not all) ADCs. The S/H captures a short slice of the analog input signal and holds it as a DC level during the time it takes the AD to convert the analog sample to a digital word. The S/H function certainly can be (...)
The circuit is used in a high speed sample hold circuit. The output swing for both circuit is enough. So can any one tell me which one is better, the right or the left? Why? 3X! 74073
Hi, I meet a problem of convergence when I use veriloga to model the SH circuit. I first use veriloga to build the model of capacitor, ideal switch and ideal opamp, but when I do the simulation with spectre, It tell me no convergence, how can I do with this problem? thx!!
With reference to It is the time to charge the hold capacitor
The exact hardware equivalent of taking a reference on button press would be a sample and hold circuit. in "older days", they have been implemented with large capacitors (e.g. a 10 uF foil type) and low input current FET amplifiers. They have been able to keep a reference may be for hours with acceptable (...)
To decide about component values, we need to know the OP and switch transistor types first. In addition, there's no particular need to give the input stage a gain > 1, it can be configured a s buffer similar to the output stage as well. A reasonable capacitor value depends on the signal time scale, sample rate and available acquisition time.
dear all good day i am a R&D engineer and search about ADC with following specs -2channel -2 sample and hold circuit -SPI interface -100khz sampling frequency wait your reply for impartance best regards
Dear all, I am designing a low-to-medium S/H circuit for an ADC. The sampling switch is a bootstrapped switch to linearize the on-resistance. I first designed a bootstrapped switch, and I simulated the waveforms and obtained DFT and THD in cadence with the calculator. After that, I also designed a dummy switch to (...)
Hi, how to suppress charge injection effect in sample hold circuit ?
I want to make a sample and hold circuit. I want to know if there is a way to simulate and plot graphically the number of time constants. To be more specific : I know from behavioral model that 1 time constant is max 30ns. The Tsample is 250ns. So the minimum UGF is 1/(2pi*tau)=5.3MHz. (...)
Hi All, In my design I would like to sample analog signal whose frequency is 350 MHz using a 600KSPs ADC. In this case I thought of scaling down the frequency from 350 MHz to around 100KHz using a sample and hold circuit. Is my idea O.K or are there other techniques that I can use to scale down the (...)
ok i'm designing a sample and hold circuit, using a mosfet and a capacitor, maybe a buffer at the output but im still not past this point yet. my question. as i'm using the mosfet as a digital switch or CLK , so ofcourse as i learnt it will be operating in the linear region. so when im applying the voltage (...)
hello everyone, i am trying to write the equation for charging of a capacitor. Vo = Vin(nT)*(1-exp(-t/30)); for nT< t<(n+1)T. where, the T=hold time for a sample and hold circuit. I have to write this equation in matlab. Can anyone suggest me the code....
Hi All, Am working on sampling analog signals. In my work I need a sample and hold circuit that can sample analog signals in GHz (10 HGz is nice) region. May somebody help me if there is a link to such a S/H circuit. Thanks in advance.
The easiest way is to use a series FET that drives a capacitor to hold the voltage. You can DC bias the gate so the FET is normally off, and has a short pulse turn on the fet. The short pulse can be either from some sort of one-shot circuit, or could be a ac coupled spike from a squarewave rising edge. If you had a much faster waveform (...)
hi, i need help for constructing a sample-and-hold together with a bit-to-symbol converter in 1 circuit board. From what i had understand, a sample-and-hold circuit consist of a input, switch(BJT or Mosfet) and a (...)
Hi, I need help to understand the circuit to be implemented in my project. Can someone provide me guidance to understand how this sample and hold circuit works? Thanks. ---------- Post added at 18:32 ---------- Previous post was at 18:30 ---------- Sorry... I need (...)
Hello, It is probably a simple question, but I struggle with this a little. I use an RF detector and I need to integrate after the detector, so I have about every 10's sample or less. If its detector, that should basically produce an envellope, is it possible just to use low pass filter as integrator? I am using LT5507 as integrator. So I ju
I have had the "pleasure" of designing a JFET based S/H product once. The key is to ensure that when "on" the JFET switch gate is roughly at the sampled signal potential, and when "off" it is pinched off as little as possible, beyond "what works" so you minimize charge injection and sampling pedestal. I did this with a secondary (...)
wats there C1?Obviously it has to be connected, too. P.S.: To answer more generally, I simply wanted to suggest the LF198 functional circuit as an example, how a S&H can be build. A specific detail of the LF198 is the feedback from output to the first stage. It's not the only way to realize a S&H, and it may need special measures
i Hello I am designing a sample and hold circuit ,whose out put will be given to ADC in ARM signal is analog signal of on time 2-4 micro sec and period >=10ms . I am using comparator before to this sample and hold circuit whose (...)
hello, everyone I have following questions about track and hold circuit. (1)What's the difference between track and hold(T/H) and sample and hold (2)how to T/H improve ADC input bandwidth? by (...)
What you suggest is a perfectly valid way of doing it and probably easier to get working accurately than a sample & hold based circuit. Keith.
I am using ADC to acquire a signal 1MHz. Would I require a sample and hold circuit before ADC? I am using ADC--> ADS5474
I tried this topology but I have offset problem . these opamps are working 500Mhz but they have offset such as 4-5mV. but I have 20mV range for every step. 2^6=64 step . so 4mV is large for me when I decreased offset I have settling problem. I didnt find any opamp with low offset and high speed at 0.18tsmc . any suggestion for hig
Thank you Frankliner. The design is a sample and hold circuit. If out of 1000 runs, I have, let's say, 50 runs where the output is not stable (oscillates) and the remaining runs result in good Harmonic distortion figure. Is that considered acceptable or good circuit?
i am trying to modify an old synthesizer to accept a 0v / 5v or 15v trigger input to trigger a sample / hold circuit. currently there is a slider that controls the sample time (frequency) of a sample and hold circuit. the dc output on scope after the (...)
Hi, all, I am designing a switched-capacitor S/H circuit, and from some documents, I found that the opamp used in the circuit takes use of a switched-capacitor CMFB, what I want to know is that, why this specific CMFB should be used here, but not a general CMFB circuit? and also any literature about (...)
hi, I design a bootstrapped switch used in a simple sample/hold circuit( a bootstrapped switch with a cap load). The bootstrapped circuit and simulation result is in the following graph. In the simulation, the blue line is a ideal switch result. the red line is using a bootstrapped switch. It (...)
Hi, all, I am trying to build a testbench for ADC in ADS, to get some behavioral information. and I got an example in the design guide, but it seems that only sample-and-hold circuit is provided there, so the question now is how to quantize the sampling results, to get the digital codes? which component (...)