operational amplifier

  1. G

    Electret MIC and MAX4466 Picking Up VCC Noise (sometimes)

    Hello there, The backgorund: I'm working in an audio module using an electret microphone and a MAX4466 amplifier, I'm using the layout recommended in the MAX4466 datasheet (datasheet Figure 2), with the only difference being there is a 100 nF cap between the MIC+ and MIC-, the presence of said...
  2. Dr. Heinz Doofenshmirtz

    Where to clamp inputs for op-amps with zero headroom?

    In op-amps where the absolute maximum input voltage range is limited to the range of the supply rails, is it sufficient to clamp inputs right at the supply rails or should they be clamped a bit lower/higher to allow for wiggle room? For example, I'm designing a single-supply audio circuit and...
  3. gdma2004

    Lowpass filter with TL072

    Hi everyone, I'm trying to implement this active low-pass filter using a TL072CP. I have simulated it in LTspice, and its behavior is pretty much what I expected. However, when I assemble it on the breadboard and analyze its Bode plot, it appears more like a high-pass filter with poor gain...
  4. H

    Need help calculating mid-band gain of an inverting operational amplifier with a capacitor in its feedback network

    Hello everyone! I'm extremely confused about this and I was looking for advice, I'm sorry if this is the wrong place to ask. I have the following inverting operational amplifier with these values: - Rs = 1k ohms - R = 10k ohms - C = 10 mF - Aol = 74dB - Zin = inf - Zout = 5 ohms I need to...
  5. Samaze123

    Why my operational amplifier TL3472IDR doesn't work properly with 1Mhz ?

    On a breadboard i'm using an Arduino Nano to produce a square signal of 1Mhz. I pass it through a volage divider to keep 1V. Until here all is working properly. Then i use my op amp TL3472IDR to make a volage follower. The op amp can't produce a correct signal and using a scope i'm seeing that...
  6. Younes Thabet

    what kind of noise can be introduced in an OPAMP conditioning circuit?

    Hello all, I have 2 almost similar PCBs for voltage and current measurement. I have used 230VAC from the outlet to test them both. The circuit in both boards is similar which is just a voltage divider to reduce the input voltage (see attached image). but I got some noise in one of them even...
  7. S

    OPA4990IDR Getting too hot

    Hi all. I have designed a PCB using the OPA4990IDR op amp in a comparator configuration. I have use the OPA as a unity gain buffer also before the comparators. The purpose of this PCB is to measure battery voltages of up to 10 Li-Ion cells (3.3V each , 38V MAX). I am having a problem tho...
  8. J

    folded cascode op ampdesign

    Hello, I'm trying to design a folded cascode op amp as shown below. I need a high full power bandwidth, about 90 to 100MHz, and a high gain (>60dB). I reach the required gain but it's hard for me to have a large full power BDW, it doesn't exceed the 500KHz. From the theory, the frequency at...
  9. J

    PSRR in op amp

    Hello, I have a question about the PSRR and the noise in an op amp. Which configuration has the best PSRR? Is it the telescopic one or the folded cascode? I know that to improve PSRR, we need to have a high output resistance and symmetric architecture ( can someone pls tell me why symmetry...
  10. J

    Operational amplifier MOSFET vs BJT

    Hello, I have a question regarding operational amplifiers. Whenever I search for some datasheets of high gain and high-speed Op Amps ( BW higher than 50MHz), I mostly find that they are made of bipolar transistors rather than mosfet. Why is it so? I've done some research and I've found that...
  11. J

    operational amplifier design

    Hello, I'm trying to design an one stage OP AMP made of a differential pair, a current load and a current mirror as shown in the picture ( the first stage only, I didn't include Q7 Q6 and Compensation capacitance) I designed the circuit to have a gain of 100V/V, a slew rate of 2V/µs, aGWB...
  12. hulage

    Sample and hold circuit simulation in Altium

    I'm done getting crap output signals. I've tried to simulate about a dozen circuits with several operational amplifiers. Filters work fine, but SAH doesn't. I give up and asking you for help. There can I find tutorials about designing circuits with OP AMPs? Also, if you got a circuit, you are...
  13. P

    OPA657 Op-Amp oscillating for unknown reasons

    Greetings, I am working on a Lidar system for a senior project and am running into issues I am unable to solve with my circuit. The project requires the use of an amplification and comparator circuit in order to take the detector output up to a level that will trigger a TDC controlled by a...
  14. alifaqil25

    What is the important of Gain Bandwidth of op amp

    Hello, I am required to design an active band pass filter and I needs to design it at high frequency around FM Radio frequency (>80MHz). Do the GBW of op amp needs to be selected accordingly to the required frequency or it does not matter? And what is GBW indicates actually?
  15. R

    DC biased opamp input resistor function

    http://www.generalguitargadgets.com/pdf/ggg_dist_plus_sc.pdf I'm looking to understand this schematic. Currently focussing on the input and power stages. Here's where I'm at: INPUT R1 is a pulldown resistor. It provides a path for the leakage current through C2 when the switch is in the...
  16. R

    Op-Amp Voltage Follower Outputs ~+Vcc when IN+ is 0V

    Hi all, I'm fairly new to working with operational amplifiers and so I'm just messing around with a few basic circuits. Had a comparator working fine to switch an LED on/off based on some variable reference voltage, but now I'm trying to get a working voltage follower. I have 2 different...
Top