Questions tagged [single-supply-op-amp]

For questions about op amps that are marketed as capable of "single supply" operation. While all op amps can be operated with a single supply, op amps that are marketed as capable of "single supply" operation typically include an input common mode range and output voltage swing down to the negative supply voltage. Always use with the "operational-amplifier" tag.

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1 answer
57 views

Does an op-amp's input-referred noise increase or decrease with decreasing supply voltage?

I plan to use the OP97F in an application using a single 5V supply, but all of its parameters are listed for +/-15V supply. There's a noise density graph showing it's valid from +/-2V to +/-15V but I'...
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1 vote
1 answer
69 views

OPA452 op-amp output voltage problem

I have a question about an OPA452 op-amp IC. I am using the op-amp as a single supply amplifier. My gain is 8, and V+ is 40V and load is 1k resistive to ground. If the input voltage is 1V I measure ...
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0 votes
2 answers
94 views

Need help to understand op-amp input resistor and capacitor network

I'm trying to understand the circuit design from this application note. Here is the figure: The author said: Resistor RIN provides a dc return path for the VS/2 reference voltage and sets the ...
1 vote
1 answer
50 views

Single transistor VCA for gate type CV signals

I am in the process of designing a sort of mini synth / noise machine and I'm struggling with the output stage. I only want sound to come out when I press the button, so based on some designs I have ...
-3 votes
2 answers
93 views

Op-amp with both inputs the same doesn't output zero [closed]

In the picture below: We have exactly the same input at both + and - pins of the op-amp's input (in the above picture, In1 and In2 are identical). Normally we must have a zero output all the time but ...
-1 votes
2 answers
82 views

Simulating ground cancelling output stage in LTspice [closed]

I've tried to simulate ground cancelling mentioned by Douglas here: The simulation cannot cancel ground noise: V3 is noise pollution, V2 is microphone signal generator, V1 main power. R8,R10,R9,C1 ...
4 votes
3 answers
746 views

TL072P Opamp behaviour

After noticing a strange behaviour from a TL072P Opamp in a circuit I was building, I decided to test my stock, coming from two different batches, side to side. I am getting confusing results when ...
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2 answers
159 views

Photodiode amplification circuit

I'm going to build photodiode amplification circuit which is then connected to ADS1115 controlled by Raspberry Pi, it has sampling 3.3k. The operational amplifier I ...
2 votes
5 answers
556 views

High precision resistance meter

I'm designing a high precision resistance meter, which will measure the change of resistance of a given remote resistor, which is not placed on the circuit PCB, against temperature. I want to do this ...
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0 votes
2 answers
98 views

Why this ZCD not working?

I have a simple drawing of ZCD by using potential divider to stepdown the voltage feeding to the inverting and non-inverting input of LM358N. The simulation result as below In practical, I connect ...
  • 607
0 votes
1 answer
48 views

Power/Sense line connections when a relay in path

I need to connect a power supply instrument with (power and sense line) to my IC; this IC is separated by a relay. Can I connect/tie the sense line of the instrument close to IC in the layout (as ...
1 vote
2 answers
106 views

Supply voltage for opamp in a current sink circuit

I want to use an opamp in a current sink configuration in order to control the emitter-base current of a PNP transistor via a digital-analog pin from a microcontroller. The circuit is as shown below. ...
0 votes
1 answer
57 views

Amplifying a pyranometer's small output using a single-supply amplifier

I am making use of theApogee SP-110-SS Pyranometer which outputs 0.2 mV per Wm-2. This pyranometer gives its true output over two cables, described as a positive and a negative output, where the mV ...
0 votes
2 answers
159 views

Band pass filter with single-supply op-amp not filtering

I am working on a university project that requires me to build a 40kHz band pass filter for receiving an ultrasonic signal. The filter is to be implemented into a portable device powered by a 9V PP3 ...
4 votes
1 answer
470 views

Op-Amp Voltage Follower not working at "extreme" voltages

I was testing the AD712 on LTSpice with a simple voltage follower. In a perfect world, I'd get this. Instead, I'm getting this. Now, I am aware that op-amps do not reach their V+ and V- voltage and ...
3 votes
1 answer
98 views

Op-Amp inverter not working at high frequencies

I set up an inverting Op-Amp with the following schematic, inputting a 32.8 kHz signal. Two identical resistors on each side of the inverting input. Bias voltage is 7.5 V, Supply voltage is 15 V and 0 ...
1 vote
1 answer
83 views

Ngspice convergence problem AD8606 simple simulation

I am new to electrical circuit simulation and I would like to simulate the behaviour of the operational amplifier AD8606 in a simple follower configuration, facing different loads. In order to do that ...
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3 votes
5 answers
280 views

Measuring bidirectional voltage drop across current shunt on positive rail

I want to measure a voltage drop across a current sensing resistor (in both polarities) on rails up to 30V using an Arduino / AVR ADC with 1V1 reference. For background, this is a part of a battery ...
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0 votes
1 answer
76 views

Are there any differences between an inverting opamp with gain X vs. a voltage divider with gain X followed by buffer?

I'm looking for the advantages/disadvantages of using one over the other, especially for low-noise applications where I'll be feeding the output into an ADC. In terms of AC response, the BW looks the ...
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1 vote
2 answers
138 views

Voltage follower configuration

for the LM4952 chip (class AB amplifier), I wanted to add an NE5532 OA in voltage follower configuration at its input. That to take care of whatever input source will be plugged into it. Is it a good ...
0 votes
2 answers
119 views

Using a voltage follower to stabilize the ground in a single supply op-amp circuit

I was building a distortion circuit using op-amps and had to figure out a way to power the op-amp using a single supply, in other words I wanted to obtain +half supply voltage and -half supply voltage ...
1 vote
1 answer
56 views

Converting a range on high side to a range on low side for very precise voltage sensing in ultra low power application

I have an ultra low power design running on CR2032 where it is critical to monitor precisely the current usage and the primary cell voltage during dev. So I added a second MCU dedicated to ...
1 vote
2 answers
124 views

SMPS Pre Regulator Minimum load

I am designing a 30 V 5 A lab bench power supply having SMPS as a pre-regulator for the linear stage which will keep the SMPS output always 4 V higher than the main output voltage. This means SMPS ...
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0 votes
2 answers
113 views

I am planning to design comparator based on Opamp but I am not getting the exact pulse output in LTspice [closed]

I am trying to simulate this but I am not getting the exact "RECTANGULR" pulse output. Kindly help me to figure out where I am going wrong. I am going to use this circuit as pulse generator ...
0 votes
4 answers
194 views

In this voltage follower circuit why isn't the output voltage equal to the input voltage?

The image below shows the circuit and the plot of vin/vout in function of time. The green curve is the voltage source that is connect to the non inverting input of the op amp (so the 10V) and the blue ...
2 votes
3 answers
150 views

Single supply op-amp saturates every time

Given a reference voltage level, I need to pick the difference with respect to that reference, amplify it and then convert it to digital. (Yes, I want to measure small voltage drops between two lines)....
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0 votes
2 answers
82 views

How to pass from a double-supply filter circuit to a single supply filter circuit?

So here is the main circuit, it's a lowpass filter-4th order bessel, so 2 sallen-key low-pass circuits in cascade. I already have all the components and transfer functions figured out but i would like ...
0 votes
1 answer
159 views

High voltage current sensing with floating isolation amplifier

I need to sense 200V (to GND) 0.5mA - 20mA DC with minimum components count. After a lot of searching I think isolation amplifier followed by post-amp would give least components count. Isolation amp ...
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1 vote
2 answers
261 views

Single-ended 3.3V guitar preamp circuit is clipping and offset

I'm designing an audio signal frontend to take an electric guitar analog output and deliver it to an ADC channel on a microcontroller. The µC/ADC are 3.3V devices (...
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2 votes
2 answers
183 views

What is the relationship between power supply rating and audio amplifier power rating?

I use many different types of Class D amplifiers in my designs. I am aware that the rated audio (RMS) power (with typical 10% distortion) relates to a sine wave which is not typical of music and audio ...
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1 vote
2 answers
98 views

Is it OK to control many (10s) of analogue switches with a single buffered op-amp?

Analogue Switch (SPDT) - DG419LEDY-T1-GE4 Datasheet: Vishay - DG41XLE Analogue Switches Op-amp - LM358PT Datasheet: LMX58 Op-amps Using a microcontroller's GPIO, and a non-inverting buffered op-amp ...
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1 vote
1 answer
118 views

Bidirectional Hall current sensor signal conditioning (shift and scale sensor output voltage)

I am using a Hall current sensor in circuitry where I need to implement signal conditioning in order to improve accuracy of measurement. The Hall sensor outputs 1 volt when measuring maximum current ...
0 votes
2 answers
123 views

Question related to a differential amplifier: Should one of the inputs be inverted?

I have seen differential amplifiers online and I want to know if the differential amplifier would still work if the input signals were half wave signal (positive half cycle.)
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2 votes
3 answers
199 views

Amplify DC signal: how to deal with real life problem ==> output is close to Vs when input signal too small OK otherwise

Hi I believe this problem must be classical and well known but I cannot find a place where it is specifically discussed: I have build a simple non inverting 2X amplifier following exactly the ...
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1 vote
1 answer
219 views

Absolute value single supply op amp circuit on TL072 or MC4558

I would like to obtain an absolute value of input signal with TL072 or MC4558 op amps (or other amp) with single supply. When I connect the circuit upper one follows the signal and adds noise and ...
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4 votes
3 answers
559 views

Unused Opamp Termination: How does it cause increased current consumption?

Usually the following configuration for unused opamps is said to be troublesome, even for rail-to-rail input & output (RRIO) opamps. Nevertheless, it is attractive because it requires no ...
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0 votes
3 answers
164 views

Level Translator 3.3V to -7V with drive

I am retrofitting a circuit in existing equipment. I need a circuit for each direction. Circuit 1: 3.3V logic input. Output is GND or -7V with a load of 20k to 200k and 2nF. 25kHz or less. Drive ...
0 votes
2 answers
78 views

opamp with single power supply

I'm trying to build a 'panner' to mix two audio signals, basically a dry/wet potentiometer for an audio effect. It works as intended when I use a dual power supply like this: But stops working when I ...
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-3 votes
1 answer
80 views

opamp dc comparator [closed]

simulate this circuit – Schematic created using CircuitLab I am trying to compare the voltages of the inverting and non-inverting terminal but no matter what input I put in, the voltages seem to ...
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0 votes
2 answers
49 views

OP2177 opamp with single supply

Does anyone know if I can use "OP2177" with a single supply without a negative voltage on V- ?
0 votes
1 answer
78 views

Any reason why the MIC920 op amp should not be used in SINGLE SUPPLY mode?

I understand that practically any op amp can be used in single-supply mode as long as the application (interface, measurement, etc) does not require dual-supply for specific reasons. Is there a ...
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0 votes
2 answers
328 views

Balanced Audio Line Driver Off Single Supply

I am working on a device that needs a balanced audio line driver that can convert an unbalanced signal to balanced and drive a balanced cable run between devices. I am looking at schematics using ...
0 votes
1 answer
99 views

How to prevent single rail ampliier power-on pop sound?

I would like to build a 9V battery powered microphone pre-amplifier and I'm encountering a design problem which I don't know how to solve: I have an opamp that serves as main amplifier which is ...
3 votes
3 answers
939 views

How to implement gain and offset in a single opamp?

I tried designer here in this page. But my particular case (Case 2) seems not working in the page. Then I Read this document and my case there, is section 4. But my calculation results are not ...
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0 votes
2 answers
170 views

Sine wave signal at resonant frequency gets distorted

I am currently at lost on what I need to do to solve my problem. I have a sine wave signal as my input, and the output is sine wave as well. At resonant frequency, the output of the signal gets high. ...
  • 319
0 votes
2 answers
551 views

What are the advantages and disadvantages of a Darlington pair? [closed]

Can the BJT transistors in a Darlington pair be of different types?What are the advantages and disadvantages of a Darlington pair? Is such a circuit able to generate power by itself?
0 votes
1 answer
90 views

Internally compensated opamp for 5V/V or more

I am using opamp for some signal conditioning circuit. I want to use opamp as voltage follower. It is mentioned in the Opamp datasheet that opamp is internallly compensated for 5/5V, 10V/V, or more ...
0 votes
2 answers
69 views

Different voltages for Single and Dual-supply (INA)

Since it doesn't matter for the Op. Amp. itself, the components presented as "single-supply" commonly relate to rail-to-rail input/output devices, which operate on lower total voltage ...
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0 votes
1 answer
137 views

Measuring Voltage from Photodiode with OpAmp

I am trying to measure the voltage coming out from my OpAmp after connecting it to my Photodiode. As a Photodiode I am using the BPW34S from Vishay and the Op Amp is the AD822ANZ from Analog Devices. ...
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3 votes
1 answer
226 views

Help figuring out an op amp circuit with two loudspeaker outputs

I have to design a circuit that amplifies a sine wave with either a AD8616 or a LTC6256 (currently using the AD8616) to a 50 ohm loudspeaker and a rated power of 0.5 W. I'm a novice when it comes to ...
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