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63 Threads found on Low Offset Amplifier
offset voltage and gain error terms need to support LSB accuracy. Bandwidth / settling time need to be well better than sampling rate, and settling time is to a very low residue error. You would have to design the amplifier for the worst case (max bits, max bit rate) or cases (if your scheme varies them independently or according to (...)
We are using the TCP303 current probe with TCPA300 current probe amplifier to measure DC average current. We are connecting the TCPA300 into a Lecroy Wavesurfer oscilloscope. The readings are coming out much more inaccurate than the ?+/-3% of reading? suggested in the current probe datasheet. The current waveform that we are measuring the
Apparently the TINA LF444 model comes with 10 mV built-in offset. According to datasheet it's rather a worst case than a typical value, but not impossible with this cheap general purpose amplifier. A straightforward solution is to use a precision (low offset) amplifier instead of asking for (...)
Its datasheet is published by its manufacturer and it says the max gain (with all spec's) is 1000. Don't you believe them or do you want poor spec's? Simply add a cheap low noise opamp to its output. The extra amplifier does not need to be an expensive instrumentation amplifier.
140dB (!!) is a voltage gain of 100 million. Then an OTA with an input offset voltage of 5mV will produce an output of 500,000V when its input is zero! What about low frequency noise being amplified 100 million times? Don't be silly.
hi, Connect a 4K7 or 10K from LM358 Vout to 0V and recheck the Vout low. E
any method to design a low offset CMOS amplifer? Without the auto-zero and chopper, besides the large size of the transistors, any other way to realize low offset? Thanks, Shawn
If resistor values are high and board is uncoated, even relative humidity could make that kind of change. At such low input level, Vio drift and things like charge pumping of ambient 60Hz/120Hz hum could be at play. A copper box and a known-stable voltage meter might be a good thing to try. I see "520mV" and "530mV" as being a bit short of resol
Hai, I'm trying to interface a thermocouple to microcontroller. As the thermocouple produces very low voltage, I've given an INA126P instrumentation amplifier to amplify the voltage. I'm using +5V as V+ and GND as V- and Vref=2.5V. But, in the datasheet it says input common mode voltage is 1.5V to 3.5V (from graph). So, I tried to add an (...)
amplifier noise and offset voltage are the limiting factors. offset voltage matters in case you want to sense DC voltage. amplifier noise can be as low as ?V for MHz bandwidth down to nV for Hz bandwidth.
If clock is not acceptable and continous-time amplifier is required, you can employ very big size device to achieve very low offset.
For best sensitivity , low offset and best common mode noise rejection use an Instrumentation Amp IC ( 3 opamps) and use the series RC to define your HPF cutoff (fc=1/(2pi RC) instead of R7 You can get these in 1
Anything you can do to use symmetry on differential output, such as loads, current mirrors, CCBDI, will help reduce offsets. Use a balanced Wheatstone bridge config with an Instrument amplifier IC. They come in all kinds, but are designed for small signals, low offset, high impedance.
Why did you use an inverting amplifier, you have a low positive input and you want a higher positive output so a non inverting amplifier seems to be the proper solution. You should use a precision opamp that has a low input offset because your input level is low and
Hi All, For an op-amp which will be used as open loop comparator, How do we simulate and judge the performance of the op-amp which include the following items: 1. Input voltage range 2. Output High voltage Vs Output low Voltage 3. Output current source and sink capability 3 Input offset voltage 4. Frequency response ( Open Loop or (...)
Can anyone please tell me what would be a perfect alternative for LMC662CN used in this circuit. LMC662CN was used because it was found suitably designed for low current measurement,has ultra-low input bias current (2 fA maximum) and low offset voltage drift (1.3 μV/oC). But since I don't have a LMC662CN IC with (...)
Why do you need the adjustments? If you are measuring small voltages, use low offset opamps or maybe an instrumentation amplifier. Keith
Just use comparator to compare the two input signals for LDO error amplifier (output feedback voltage and reference voltage). If Vfboffset, comparator outputs a signal to pull low LDO power PMOS. Also another comparator (Vfb>Vref+offset) can be used for overshoot suppression.
You can also feed an offset voltage to the reference input. But it should be low impedance, e.g. buffered by an OP voltage follower.
I am thinking of using a precision low frequency op-amp to null the offset voltage of a wide bandwidth fully differential amplifier (LT6600) by sensing the closed loop offset voltage across the input terminals and driving a suitable correction current into one or other of the virtual earths to correct the (...)
what kind of distribution the amplifier offset looks like? For example, auto zero type of low offset amplifier.
Hi all, I want to measure 50?V, 50/60Hz AC signal. with gain of say 100, in low cost way also I need to keep supply current of the amplifier below 100uA. I searched precision instrumentation amplifiers but either offset voltage is more or supply current is more. Can I do it with normal opamp having (...)
Do you have a link or reference where you got the circuit from? The reason I ask is because the feedback amplifier looks like it produces a current output and VGA3 presumably doesn't have a low impedance voltage output otherwise the circuit wouldn't work. An explanation of the circuit requires some knowledge of the internals of the (...)
Burr-Brown of Texas Instruments offers some very good opamp or instrumentation amplifier. Try the following link:
You can employ a rail-to-rail op-amp, supply it of +5V and configure it as AC amplifier with 2.5Vdc offset .. see attached picture .. The gain can be calculated in such a way that the max output signal is within 2.5Vdc - +/-2.5V range .. Here is an example of low-voltage rail-to-rail opamp:
The offset-QPSK with half-sine pulse shaping modulation selected for the 2.4 GHz PHY is equivalent to minimum shift keying (MSK), which is a constant envelope modulation scheme. This allows the use of simple, low-cost and relatively non-linear power amplifier designs. I hope it can help. Mazz
The optimal amplifier selection depends also on the electrode properties, but low-noise FET OP is generally a good choice. JFET is possibly preferable to MOSFET because of a lower 1/f noise corner frequency. FET instrumentation amplifier is best for differential signal acquisition.
There is other kind: offset-stabilized amplifier - which consists from 2 branches. The first one is high speed, low gain, high offset. The second one is low speed, high gain, low offset. Of course it works with a proper frequency compensation. So when chopper (...)
I wander whether you drawed the schematic completely. I designed a fourth order filter with DC offset cancellation.the feedback block acts as a LPF to extract the dc signal of the output. And the BW of the LPF is very the value of R and C is very large. For the main signal path,the load is only R. when you design the amplifier, This shoul
Did you look at the datasheet for the OP97 opamp? It has extremely low input offset voltage and offset current. You could use an ordinary low noise opamp and trim the offset yourself with a trimpot.
I recently experiences power surge at home. the relay of my JVC amplifier switches off when I increase the volume and turns on again at very low volume. what should be the likely cause?
Since you won't be needing a high output swing you can go for a single stage telescopic cascode differential amplifier that will give you a decent gain with good PSRR and low power consumption. The main problem with this is the systemic offset which may or may not meet your spec of BGR+10mV. Alternatively you can go for a typical (...)
besides of low loop gain , and the offset of error amplifier. there are any other reasons ? thx
Hi, The input offset voltage is amplified by the closed loop gain and appears at the output,the input offset current produces an output voltage equal to offset current multiplied by the feed back resistor. So in applications where the closed loop gain of the amplifier is not high, by choosing a relatively (...)
I designed an integrator, it is actually a low pass filter, a simple one stage differential amplifier with one terminal input short to the output and connected to a capacitor. In this case, the input is a signal, the output would be the input average voltage. All the transistors work in the weak inversion. The integrator has a tail current of 100pA
Hi, You measure offset voltage by configuring the opamp as a high gain closed loop inverting amplifier with zero input voltage and with relatively low feedback resistor such that the effect of offset current is negligible in the measurement. The voltage offset referred to input is then calculated by (...)
Check the book Design of low-Voltage low-Power Operational amplifier Cells by Ron Hogervorst. Also check this pdf. It has all the Pelgrom's equations and offset equations for the folded cascode OTA.
It's sure to use low-voltage devices in the design of BG because of good matching. But local regulator is needed for BG. To reduce the input offset voltage, it's better to use HV-LV mixed design design for the error amplifier.
hi, all, this is a chopper-stabilized amplifier. it is a low-offset, low-noise amplifier, used in high precision applications. this amplifier is similiar with ICL7650. CA and CB (about 100nF) is external nulling capacitor. pls help to analysize the nulling principle of (...)
I am designing the four channel led driver with charge pump, I need four channels are perfect matching with the goal current and the output resistor is low, so offset cancell amplifier is needed. But I don't know the auto zero and chopper amplifier which one is suit for my necessary. Due to my knowledge, the auto zero (...)
biggest difference for the instrumentation amplifier is 1. tiny input side loading 2. low offset, accurate. 3. high linearity (precision) 4. usually low speed 5.
since the offset is pretty low, the nonideal ground will induce some offset.
Maybe you can use the LMV301 - low Input Bias Current, 1.8V Op Amp w/ Rail-to-Rail Output OPAMP .. Regards, IanP
how to design a low offset op ? thanks
sine wave output? then filter it and you'll have a nice sine wave square wave output? differential input single output amplifier/comparator can do it. if your input is symmetrical, and the amplifier/comparator is low offset/noise, 50% duty cycle is ensured.
Abstract ? This paper presents a programmable gain amplifier for dual band (GSM900/DCS1800) low-IF receiver. It is a negative feedback approach to achieve high linearity requirement. In addition to the amplifier, anti-alias filtering and dc offset removal are included for the following IF signal processing. (...)
Hi, friends, a low pass filter is usually used to cancel the DC and low frequency offset caused by mismatch in limiting amplifer. However, I have difficulty in deducting the theorectical function. Could anyone of you help me on it? Or, are there any materails on this topic? Thank you all in advance.
hello all, i am designing a 10 bit ADC, and i need an architecture for a comparator that can achieve a resolution of 1.6mV. any ideas, papers, books, references? many thanks Use a low-gain amplifier folowed by a latch comparator, and output offset compensation. Bastos
How to design an low noise amplifier (BW<1K) that has very low input refer noise (or very low offset) ? I think Autozero and Chopping is not good enough. If I can use offchip JFET like LSK ( ), how to do the following design? Also, I found an ultra low noise OpAmp from TI (...)
Can someone tell me how to design a low supply voltage bandgap?