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Questions tagged [transimpedance]

The transimpedance of a device relates the current through the input of the device to the voltage across the output of the device.

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How much variation in the transimpedance gain of the TIA is acceptable?

I have designed a transimpedance amplifier with a transimpedance gain that varies from 113.1dB to 111.46dB over a current input range from 200nA to 6uA. Is this variation in transimpedance gain ...
Vishesh Gupta's user avatar
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Finding poles of the transimpedance amplifier

I`ve been having problems with finding poles of one transimpedance amplifier. Acording to LTSpice the first pole should be somewhere around 1.6MHz, but I cant get that (I am getting about 200MHz). I ...
Огњен Пискулић's user avatar
1 vote
3 answers
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Photodiode Circuit Output Saturating to 0V. Is there a way to salvage these boards?

My colleague and I recently designed and ordered a PCB intended to capture red laser light using a SFH2440 photodiode. We used the analog devices photodiode circuit design wizard to design the ...
Jort2750's user avatar
-1 votes
1 answer
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Sensitive Transimpedance Amplifier frequency bandwidth [closed]

I've built the transimpedance amplifier based on this project Sensitive Transimpedance Amplifier Oscillates. I've used op amp LMC6001, symmetrically power 5 volts, feedback resistor Rf = 100MΩ, ...
Paweł Chmolewski's user avatar
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3 answers
61 views

Does TIA amplifier minimize the capacitance of a photodiode?

Let's say we have a photodiode modeled as follows where Cs represents PD capacitance: We can say that, the larger the Cs the slower the response time of the photodiode. Now we can use this photodiode ...
cm64's user avatar
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5 votes
2 answers
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Filter non-inverting input of operation amplifiers or directly to GND?

In the following configuration on this operation amplifier (OPA838), which is transimpedance configuration, can I connected the non-inverting input directly to GND, or should I use this filter? Not ...
Andromeda's user avatar
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1 answer
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Connecting an op-amp to a second-stage amplifier: loading effect considerations

I designed an amplifier with an OPA838 as follows: First scenario: I want to connect the OPA838 to a next stage voltage LNA (Low Noise Amplifier). What components or circuit should I add to my output ...
Andromeda's user avatar
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Transimpedance amplifier oscillating at high gain setting on PCB only

I am trying to make a bare minimum transimpedance amplifier for a very large Si photodiode (Thorlabs FDS1010). My circuit is just like in the picture except my digipot is an AD5272-100kohm and my ...
selene flemming's user avatar
0 votes
1 answer
123 views

Transimpedance amplifier with OPA838 - instability

I have the following circuit as a transimpedance amplifier for ultrasound application: I checked all the possible criteria for the stability of the circuit, including phase margin, step response ...
Andromeda's user avatar
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1 answer
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How does this Precision, High-Speed Transimpedance Amplifier work?

I am confused by the equivalent circuit of the OPA380, a precision Transimpedance Amplifier from Texas Instruments. The internals of the amplifier are pictured below: I assume the integrator and the ...
Virgil_Tibbs's user avatar
2 votes
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Simulation of transimpedance amplifier in LTspice

I am trying to simulate a circuit that is presented in a research paper by Dr Behzad Razavi. I am using LTspice for the simulation (please see the attached image and netlist for the circuit). I am ...
Masood Salik's user avatar
4 votes
3 answers
272 views

How/why exactly does this JFET work as a current source?

I am designing a mic amplifier with a transimpedance amplifier circuit. The mic is connected to a JFET. I know how a transimpedance amplifier works and that it works by converting current into a ...
LEXOR AI's user avatar
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0 votes
1 answer
132 views

High pass filter after TIA is not behaving as expected in LTspice

I have the following schematics to amplify a current signal modulated at 10 kHz. The first stage is a transimpedance amplifier with a -3dB bandwidth of 72 kHz. The second stage is a high pass filter ...
oscar garcia's user avatar
0 votes
1 answer
79 views

Right transimpedence amplifier choice for input range

I have a device that produces a ±30 nA signal and I'd like to measure this to a 0.1 nA precision. Since the currents are so low and I don't have much time to make mistakes, I am planning to use a TIA ...
JoVi's user avatar
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1 answer
118 views

Putting a RC filter after the photo-diode to AC-couple the TIA gain stage

I have been designing a photo-diode circuit which separates out DC and AC signal of the photodiode. I am using MAX4007 as the current mirror for the DC branch and I am using OPA858 as the ...
Wu Eric's user avatar
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Determine feedback capacitor values for transimpedance amplifier

I need to decide feedback capacitance Cf for the for transimpedance amplifier. I have the confusion. Which equation is appropriate for finding the Cf? Cf= 1/(2piRf*fp), where fp is the frequency enter ...
GMS's user avatar
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1 answer
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how to measure leakage current across a zener diode with a transimpedance op amp

I am trying to measure the leakage current of a SMF36CA zener diode. I am doing this with a transimpedance op amp (LMC6062IM/NOPB). Attached is the circuit I am using. The amp and diode in the circuit ...
Temujin's user avatar
0 votes
1 answer
162 views

Transistor transimpedance amp design for photodiode digital input to arduino at 1MHz

I would like to use a photodiode with an atmega328 to detect pulses of light from a toothed disk (illuminated by IR from the far side) at around 1MHz. Its to detect mechanical jitter in the rotation ...
Pete's user avatar
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2 votes
1 answer
226 views

Transimpedance Amplifier Not Outputting Voltage

I'm trying to build a transimpedance amplifier to convert the current from my photodiode to a voltage that can be read using an ESP32. The components I am using are: OPA170AIDRLT Operational ...
FridgeMagnetPoet's user avatar
1 vote
1 answer
52 views

Would more connectors introduce more noise for low-frequency current signal?

General question When measuring the weak amplitute low-frequency (DC) current signal (in 0.1 - 1 uA) transmitted through FFC cable and connectors to a PCB with transimpedance amplifier (TIA) and ADC, ...
Yuanyi Wu's user avatar
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IR LED and Photodiode (G10899-01k) to make NIR sensor

I am working on a final project to detect glucose. I am using IR LED of 1200nm spectral wavelength and a photodiode (G10899-01k) of 500nm to 1700nm spectral range. I have used a transimpedance ...
J.Kirui's user avatar
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Cannot Find MOSFET Transconductance - Incredibly Confused

I am tasked to find the gain of this small signal circuit drawn in my work. I have absolutely, NO idea how the professor came up with his answer. I would e-mail him, but he doesn't respond on weekends....
willbanks's user avatar
1 vote
3 answers
599 views

What are the pros and cons for the various photodiode circuit arrangements?

I've been messing around with photodiodes do measure relative light intensity from very low light to very bright conditions. My search for information on photodiodes and the circuits they are ...
Ender's user avatar
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8 votes
3 answers
692 views

Why does using a second analog switch reduce gain error?

From the analog website this switchable gain amplifier is shown. It uses a second switch S2 to reduce gain error from S1's on resistance. Why is this the case?
W30's user avatar
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1 answer
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BPW34 Photodiode TIA amplifier

I have a problem with circuit, for some reason I always have 4.8 volt in output. Like a: 4.8 V - when I put finger on photodiode 4.83 V - in room light 8.27 V - when I light it with IR laser What am ...
Yuri Tsiomra's user avatar
0 votes
2 answers
178 views

Low gain transimpedance amplifier

I have an op-amp based current-to-voltage converter, where the input current is summed from a number of LM13700 OTA's. The signal is audio, so the bandwidth of interest is up to \$20\mathrm{kHz}\$. ...
Timo's user avatar
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3 votes
2 answers
540 views

Sensitive Transimpedance Amplifier Oscillates

I built a sensitive transimpedance amplifier for a photodiode. Motivated by this question, I am attempting to push the limits on sensitivity. I have some experience with sensitive transimpedance ...
Mattman944's user avatar
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2 votes
3 answers
147 views

Transimpedence amplifier with photo-transistor linearity

Given that the irradiance and collector current for a (random) photo-transistor is linearly correlated like below. Then I am wondering why the output voltage graph of the transimpedence amplifier ...
W30's user avatar
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1 vote
2 answers
132 views

Voltage output range of PSD circuit

I saw this circuit the other day on here: What is the basic circuit to wire up a position-sensitive detector, or PSD? From what I understand from the answer given, the voltages X1 and X2 can be used ...
joe's user avatar
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1 answer
157 views

T-network feedback of op amp [duplicate]

I want to know how the equivalent resistance of T network feedback in this op amp configuration is calculated?
BlackHawk's user avatar
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0 votes
1 answer
91 views

Transimpedance amplifier resistor calculations

How are the values of resistors in this transimpedance amplifier calculated? Also, why is a resistor divider used in the feedback path?
BlackHawk's user avatar
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1 vote
1 answer
149 views

Feasibility of high-speed omnidirectional communication through infrared light

I am currently working on the design of a low-cost communication system based on IR LEDs and photodiodes for my research project. The goal is to transmit data with ~100ns pulses across ~0.5m distance (...
Wjx's user avatar
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0 votes
2 answers
297 views

Input bias current calculation

I have a VBP104FAS connected as above with the LMP7721 opamp to produce an output voltage from the photodiode's small input current. I am trying to calculate the input bias current I need as I am ...
user1397215's user avatar
0 votes
2 answers
235 views

Transimpedance amplifier circuit with uniform light input gives a sine wave output

I am trying to build a transimpedance amplifier circuit on a PCB (as in the figure below). Although I have run a SPICE simulation and got the desired results, I wanted to test it out on a breadboard ...
Nikhilesh's user avatar
4 votes
3 answers
955 views

DC transimpedance amplifier feedback capacitor

I am designing a simple photodiode light sensor circuit. The circuit will use a transimpedance amplifier to generate a usable voltage from the light level detected by the photodiode. The most basic ...
J.P.'s user avatar
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0 votes
2 answers
154 views

Can very small currents be accurately measured using only standard analog electronic components on an IC? [closed]

Let's say, for example, that I have a photodiode, which produces electrons in response to the amount of light. What is the theoretical lower limit that can be accurately measured only using basic ...
Ching Chung's user avatar
1 vote
0 answers
429 views

Designing a guard ring for a transimpedance amplifier

I am at that stage of a PCB design where I need some guidance on guard rings. The Application: The application is a photodiode circuitry (using a pin photodiode and transimpedance amplifier.) The ...
LabMat's user avatar
  • 161
3 votes
1 answer
1k views

Photodiode bias in TIA?

When I see TIA schematics, I can see either the photodiode to GND or against VCC. What is the difference?
nowox's user avatar
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-1 votes
1 answer
144 views

Photodiode circuit unstable measurements on MCU ADC [closed]

I'm working on a fluoresce detection circuit. I have a lot of unstable measurements on the output of my second amplifier with the ADC. With the multimeter I have stable measurements. How can I smooth ...
Ruben's user avatar
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0 votes
0 answers
117 views

Measuring <10 pA of photocurrent using transimpedance amplifier

I am working on a project that measures low intensity light. The photodiode I am using an OSD35-5T. This is a large surface area photodiode. The idea is that the large surface area would absorb/...
LabMat's user avatar
  • 161
0 votes
1 answer
1k views

Feedback resistor and capacitor calculation for transimpedance amplifier

I am designing a transimpedance amplifier using LTC6268-10 from Analog Devices. The photodiode that I use is S9055-01 from Hamamatsu and the laser source that I use has a power of 10mW with the ...
Kailash Kumaravel's user avatar
0 votes
1 answer
127 views

Photodiode Current Calculation for Simulation

I am designing a transimpedance amplifier and was trying to simulate the circuit to study its characteristics. I came across this online design tool provided by Analog Devices that builds the ...
Kailash Kumaravel's user avatar
-2 votes
1 answer
85 views

Is this a transimpedance amplifier?

Help needed on the below image: is this considered a transimpedance amplifier? With the Vo of 3 V given, can I find out the current source current? Since this current source from 0:255 μA (28 bits), ...
Bill's user avatar
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0 votes
0 answers
274 views

Current sense resistor vs transimpedance amp vs hall effect current sensor for instrumentation?

I'm using a photomultiplier tube; this creates a current output relative to the number of photons incident to it, on the magnitude of microamps. So, I need a precise and accurate way of measuring very ...
T.S's user avatar
  • 107
0 votes
1 answer
266 views

High frequency photodiode laser receiver strange output

We've built this transimpedance amplifier circuit to receive 10kHz pulses from a laser. The laser is driven by a square wave signal generator and is pulsing correctly. We expected to see a square wave ...
Zayd A's user avatar
  • 13
0 votes
1 answer
574 views

Understanding noise in transimpedance amplifier

So I've been studying on TIAs for the last days and understood everything except the term of "noise". Let's take this TIA as an example: https://www.ti.com/lit/ds/symlink/opa380.pdf?ts=...
Dakalaom's user avatar
  • 551
1 vote
2 answers
269 views

Benefits of Transimpedance amplifier with a non-ground reference

Regarding this question -> Transimpedance amplifier with a non-ground reference What are the benefits of having an ideal absolute static reference voltage instead of just simple GND on the non-...
Dakalaom's user avatar
  • 551
-1 votes
1 answer
203 views

Transimpedance and resistor bias in IR transmitter

I've been studying the optical (photo-diode) transmitter and receiver circuit for a while. There's a case that I can't understand the difference. In the optical receiver bias circuit, what is the ...
Hossein Ameri's user avatar
10 votes
7 answers
3k views

Transimpedance amplifier for very low currents

I am currently working on a project, which requires me to measure the very low currents (approximately in the range of 100 pA to 10 uA) from an electrochemical sensor. The sensor is kind of a new ...
Rata's user avatar
  • 111
0 votes
1 answer
256 views

Multi stage & gain opamp output voltage issue

I am currently facing an issue with an opamp circuit. The design consists of a transimpedance amplifier followed by a buffer stage and then followed by 6 non inverting gain stages (each stage 4 times ...
LabMat's user avatar
  • 161