Questions tagged [transimpedence]

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69 views

Why is the resistance on my PCB low?

I am designing a PCB for a LED, photodetector (several different tried), TIA (OPA380), and linear regulator (LT3042 to reduce noise). It's on FR4 from OSHPark. When the LED is on the photodetector's ...
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0answers
45 views

Why would a common Gate MOSFET (instead of a resistor) reduce noise in a TIA?

simulate this circuit – Schematic created using CircuitLab I am reading a paper on TIA for optical recievers. On one of the improvements regarding the noise the writers replace the feedback ...
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3answers
72 views

Transimpedance Amplifier and Photodiode for BFSK

I am working on my first transimpedence amplifier circuit and am having some trouble. I have am looking to reconstruct a BFSK signal modulated on an LED. The BFSK signal uses a 50kHz sine wave at 80mA ...
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2answers
68 views

Op amp output voltage swing vs noise

Staying within an op amp's specified output voltage range, how does a difference in output swing affect the op amp's noise applied to the output signal? Obviously by increasing gain, we amplify the op ...
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1answer
96 views

Introducing SiPM Array to an Op-Amp

I'm working on a transimpedance amplifier circuit, but it appears that there are issues reading out a signal. The source is comprised of sixteen individual SiPMs in parallel with each other, ...
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1answer
102 views

Transimpedance Amplifier Gain Analysis

I'm trying to go through a mathematical gain analysis of a closed-loop transimpedance amplifier circuit, but I'm having issues trying to relate the block diagram to the actual circuit. simulate this ...
2
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1answer
323 views

Norton Op-Amps advantages

I have been reading about Norton Operational Amplifiers, I get a good idea of how they work, even at the transistor level, I understand that difference current in = voltage output. What I have been ...
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2answers
47 views

Transimpedance AMP, Active HPF, phototdiode (updated)

The original post is here Transimpedance AMP, Active HPF, phototransistor I decided to change back to a photodiode instead of a phototransistor since I have used one for a similar experiment in the ...
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0answers
69 views

How does one calculate output voltage noise of a current output DAC?

I am using a current output DAC connected to a voltage reference and a transimpedance amplifier. I know the noise characteristics of the voltage reference and the amplifier. The DAC simply lists "13 ...
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1answer
154 views

Topology for ideal cutband response (-20dB per decade per order) for passive, low pass, constant output impedance filter

I am trying to develop a low-pass constant output impedance filter. The output impedance must be within ±10% of 5Ω from DC up to 1GHz. The filter is driving an open load (>10M) and must filter current ...
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1answer
71 views

How to calculate the maximum amplification of a transimpedance amplifier

I want to calculate the maximum amplification that I can get out of my transimpedance amplifier and I'm struggling a little bit with how to do determine this value. Is the amplification simply the ...
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0answers
51 views

Difficulties simulating transimpedance amplifier

I am developing a transimpedance amplifier as an assignment for a faculty course and I am running into problems when trying to simulate my circuit in ADS Keysight, even though I am quite sure how my ...
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2answers
151 views

Transimpedance amplifier with diode feedback

Can someone explain the effect of capacitor and diode on the below circuit? Since when injecting 0.2uA (instead of photodiode)to the opamp with only a resistor(1Mohm gain) feedback I am getting a ...
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2answers
541 views

Determining Output Resistance of Transresistance Amplifier

I'm really inexperienced when it comes to operational amplifiers, but I'm trying my best to learn more about them. That being said, I'm currently having trouble understanding the transresistance ...
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1answer
154 views

Current-to-voltage opamp in DAC application: snubber network between inputs

In transimpedance (or current-to-voltage) opamp application for DAC, it is reccomended to put at the opamp inputs a capacitor (together with a snubber RC network through the feedback resistor), in ...
2
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1answer
60 views

Measuring integrated current

I want to measure the amount of light striking a photodiode in a specific time window (about 1ms). In this window, we get \$10^6-10^7\$ photons, which get converted into electrons with about 80% ...
5
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1answer
89 views

Large dynamic range current sense 1uA - 100mA

I am looking at large dynamic circuits and came across an interesting project by ETH Zurich called the rocket logger - https://rocketlogger.ethz.ch/ I am a little confused by their current sensing ...
2
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1answer
483 views

Origin of increased noise in BF862/OP27 charge amplifier

For the amplification of piezoelectric sensor signals I am currently building a charge amplifier with a low noise JFET frontend utilizing an NXP BF862. The amplifier design is based on application ...
3
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1answer
57 views

Phase shift near saturation mitigation in input stage amplifier — How does this work, why does this work?

I'm trying to understand how this circuit works on the input stage to the 4192A Impedance Analyzer. Apologies for the quality... this is the best scan I could find. The design is furnished with the ...
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1answer
181 views

where do i find max short circuit current of photodiode?

I'm trying to convert the current signal from a photodiode to voltage through a transimpedence amplifier. The photodiode is put in photovoltaic mode in order to get the greatest accuracy and lowest ...
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0answers
91 views

Electronics interface circuit for PIN Photodiode

I am designing an interfacing circuit for PIN photodiode which will be used in NIR spectrophotometer project. The PIN diode is <...
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3answers
160 views

Photodiode in photoconductive vs photovolatic configuration

I want to use a photodiode to measure light intensity, but I am not sure if the photodiode should be used in photoconductive or photovoltaic mode. From my understanding the photovoltaic ...
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2answers
139 views

SPICE circuit to find AOL and noise gain of Transimpedance amplifier

In Chapter 10 of Art Kay's book "Operational Amplifier Noise", he gives a SPICE circuit (pp.179) that can be used to generate the noise gain, AOL, and current-to-voltage gain. Could anyone explain to ...
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2answers
156 views

Current feedback amplifier input structure

This is an input stage of some obsolete CFA (current feedback amplifier): Current feedback amplifier is a transimpedance amplifier, which converts current signal at its input into voltage signal at ...
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2answers
68 views

Measuring current vs voltage

Let's say that I have a periodic charge build-up across the capacitor C1. I could either choose to measure the current using a transimpedance amplifier as shown below or could measure the voltage ...
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2answers
151 views

Photo multiplier tube and lock in amplifier

My photomultiplier tube is connected to a Transimpedance amplifier for routine experiments. However for an experiment I need to connect the output of the PMT to lock in amplifier (SR 865A). The manual ...
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1answer
85 views

multiplex multiple photodiodes to one transimpedance amp

TIA = transimpedence I have lots of photodiodes for barrier detection, I tested one photodiode with one TIA op amp, and it was OK 1) Now I want to multiplex multiple photodiodes for my project, and ...
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1answer
107 views

Filtering current spikes in photodiode transistor selector

I am building a circuit for sensing photocurrent from a photodiode. The diodes are manufactured with selection transistors to form an active matrix and below is a model of a single pixel consisting of ...
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1answer
376 views

Transimpedance amplifier PCB layout

I'm trying to replace an avalanche photodiode board + external voltage amplifier combination that suffers from RF pickup due to cabling between the diode and the amplifier as well as low bandwidth due ...
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0answers
279 views

Photodiode Amplifier Circuit Design

I'm working with a mid-infrared (~4um) photodiode model Lms43PD-03-CG (Datasheet) and a matching LED (Datasheet). (I can't switch from this photodiode/LED pair) I'm trying to make a functioning ...
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2answers
660 views

Bootstrapped Transimpedance Amplifier (TIA) - High Frequency Instability

I have constructed transimpedance amplifier in the hopes to achieve both high-gain (5kΩ) and high-bandwidth (50MHz) performance using the FGA21 photodiode, the OPA657 Op-Amp and the 2N2369 Transistor. ...
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1answer
157 views

Transimpedance Amplifiers on PCB

I have several transimpedance amplifiers on my board, and I want to avoid the need for a negative power supply, but I can't see any way around it (except for running the current through a resistor but ...
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2answers
589 views

Reducing Transimpedance Amplifier Noise

I'm investigating a noisy output of a Femto DHPCA-100 high speed transimpedance amplifier (http://www.femto.de/en/products/current-amplifiers/variable-gain-up-to-200-mhz-dhpca.html). The final ...
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0answers
108 views

Whats going on with my transimpedance amp?

Pulling my hair out with this design. I have the following design which was done using analog devices Photodiode Circuit Wizard tool so it should work. The current source in the schemeatic is the ...
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2answers
281 views

Transimpedance Amplifier (TIA) - How to shunt high current spikes?

I am working on the design of a high-bandwidth transimpedance amplifier (TIA) to detect a relatively weak optical signal (100μW) but also be able to withstand short pulse, high power optical signals (>...
0
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1answer
380 views

Transimpedance amplifier transfer function

I am learning analog design. I am trying to understand transimpedance amplifier using Op-Amp. Here is my transfer function. My understanding is assuming Node Va as virtual group I got (Vout= -Iin*Rg) ...
3
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2answers
180 views

Double Peak Phenomenon in Transimpedance Amplifier Simulation

I'm simulating a transimpedance amplifier circuit in order to replicate a phenomenon that my team is experiencing. The phenomenon can be seen below in the image circled in red: My photomultiplier ...
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3answers
110 views

Strange Waveform at high frequency from transimpedence amplifier

Using a simple transimpedence amplifier setup, I was able to measure noise from the output waveform by applying a small signal to the non-inverting terminal, while the inverting terminal receives dark ...
2
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1answer
321 views

Large drift (temperature could be a culprit) in this circuit. Anyone can help?

Purpose: Amplify the differential voltage out of a bi-cell photo-diode. Amplification has to have a high gain as we are looking into nm level displacements of the IR beam centroid emitting the bi-cell ...
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2answers
502 views

Transimpedance amplifier bandwidth limit [closed]

What limits the bandwidth you can achieve on a transimpedance amplifier? Why can you not take measurements at say the GHz range? I'm guessing it has something to do with an RC element in the circuit. ...
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1answer
633 views

Causes for Saturation in Transimpedance Amplifier Circuit

I have a transimpedance amplifier circuit with a Silicon Photomultiplier as shown below: simulate this circuit – Schematic created using CircuitLab We're using the SensL MicroFJ-60035 Silicon ...
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1answer
84 views

How to use a photodiode over a broad range of optical powers

I am using a GaAs photodiode to pick off a small amount of the light of a high-powered infrared laser, supply this to a PID loop and thus have a way to stabilize the intensity of the laser. The thing ...
0
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1answer
237 views

Importance of laser numerical aperture in selecting photo diode

I want to design a circuit in which the laser light will be detected by a photodiode. I just wanted to know how the laser numerical aperture will affect the photodiode selection. Am I have to ...
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1answer
171 views

Transimpedance amplifier circuit for water conductivity

I'm trying to understand the application of the water electrical conductivity measurement circuits based on transimpedance amplifier. Here the picture of general TIA configuration And here what I'm ...
2
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5answers
657 views

Timing Improvements to Silicon Photomultiplier Transimpedance Amplifier Circuit

I'm designing another Silicon Photomultiplier circuit. Right now, it is in the theoretical stage. My team and I have made numerous circuits, and the basic template is below: simulate this circuit &...
3
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2answers
403 views

Trans-impedance Amplifer with a Fully-Differential Amplifier

I'm designing a trans-impedance amplifier (TIA) for a fairly fast Avalanche Photodiode (APD), to amplify pulses of 1mA that last few nanosecond. I found a solution that have just enough bandwidth with ...
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1answer
693 views

Designing a senvitive frequency to voltage converter

I need to make a battery powered frequency to voltage converter that will monitor very minor frequency changes, around 100Hz with base frequency of 3-5MHz (may vary during operation); something like a ...
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2answers
1k views

Gain and Rise Time with Transimpedance Amplifier Circuit

I'm working with a transimpedance amplifier circuit using a Silicon Photomultiplier. This circuit is the recommended transimpedance circuit for reading SensL's silicon photomultiplier. A link to ...
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1answer
255 views

Photodiode max. Output power?

I am designing a transimpedance amplifer to run at 10mA in 100uS to detect proximity of an object (low power application) I am intending to use the VSMB1940ITX01 IR LED and the VEMD6110X01 IR ...
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2answers
681 views

Stability of saturated amplifier and overdrive recovery

I have two questions. First paragraph is background, second is questions. Background: I have a photodiode amplifier (low capacitance APD + fast transimpedance amplifier) that has a nice response ...