configuration recommendation for stable driver

[yefj]

Hello, I am starting to design a new design for a driver.So i opened a new thread with your permission in order not to mix the old with the new.
Specifications:
BW of 2MHz will be good.
10mW input needs to be interpret into 30mA on a load coil.
The FM coil data:
sesitivity: 450 KHz/mA
3dB bandwidth 2.2MHz
resistance 2Ohm
inductance 1.5uH

previously you recommended me to use a combination of AD8033 and a MOSFET

https://www.analog.com/en/products/ad8033.html#product-overview

could you please recommend me some good configuration of two of those element .
The main thing i need it to be stable.no oscillations at high frequencies as much as possible.
Thanks.

 

[yefj]

UPDATE:
Hello i have found a configuration in the attached article.
could you please reccomend me a suitable opamp to use?
Thanks.

 

[D.A.(Tony)Stewart]

I already provided a solution. Yet the problem was the shunt capacitance creating a high Q resonance.
What has changed? There is no need for transistors.

 

[yefj]

Hello Tony,could you please give me an intuition why AD8033 is more suitable then LT1028?

https://www.analog.com/media/en/technical-documentation/data-sheets/1028fd.pdf

Thanks.

 

[D.A.(Tony)Stewart]

The AD8033 has a wider Vcm range, and needs low C loading so it must be located at the load without coax or parasitic C load on the coil.

The LT1028 has low Rout open loop value 80 Ω and has more phase margin at Av=+1 with LC loads but costs 5x more. So in your case go for better performance then cost-reduce later. Eliminate all unnecessary C loading. Ultimately LT1028 does not have enough slew rate for your previous examples of a 10 kHz pulses with 11V/us at Av=-1

However your detailed requirements to compare are missing.
e.g. If you are using PWM then consider https://www.analog.com/en/products/max40056u.html

 

[yefj]

Hello Tony , The YIG was Cristal clear single tone when I used power supply for FM input .
The big problem I had is Noise delivered to the load .
Could you please recommend me a manual for similar case which I could predict the noise I would have .
I know noise could come from traces or bad decoupling the components themself.
Could you please recommend a manual where I could plan properly the noise?
Thanks

 

[D.A.(Tony)Stewart]

Here with forward compensation to speed up slew rate.

 

[D.A.(Tony)Stewart]

Noise is a big subject.

Define your noise properly to be more specific.

--- Updated Feb 2, 2024 ---

If you cannot eliminate C load effects then you must compensate to match coil current to input.

 

[yefj]

Hello Tony , i am sure that the basic functionality will work.
The problem will start at stability and noise.
Currently i am building a setup of signal generator and a scope and using automation to get bode plot of the real circuit.
How do you reccomend to investigate noise in real life?
Thanks.

https://www.analog.com/media/en/technical-documentation/data-sheets/AD8033_8034.pdf

 

[D.A.(Tony)Stewart]

Noise reduction is broad spectrum of engineering. I do not know what you know or need to know.

My best advice is to read EMC by Henry Ott. I read this 40 yrs ago and it fills the gaps in experience you may need. It is still relevant today but not specific to YIGs. cabling, grounding, filtering, shielding, digital circuit grounding and layout,

Henry W. Ott Electromagnetic Compatibility Engineering by Henry W. Ott, Hardcover | Indigo Chapters | Niagara Pen Centre

Praise for Noise Reduction Techniques IN electronic systems \"Henry Ott has literally 'written the book' on the subject of EMC. . . . He not only knows the subject, but has the rare ability to communicate that knowledge to others.\" —EE Times Electromagnetic Compatibility Engineering is a...

thepencentre.com

Today if you know the right Prompts you can get quick answers from OpenAI GPT 3.5 or 4.0 as long as you specify to exclude and include the right prompts

• Neighborhood/Community Noise:
  • Residential Noise: Noise in residential areas from neighbors, parties, etc. (LOL)
• Electronic Noise:
  • Electromagnetic Interference (EMI): Unwanted signals that interfere with electronic devices.
  • Radio Frequency Interference (RFI): Interference in radio signals caused by other electronic devices.
• Social Noise:
  • Conversations: Talking and discussions in public spaces.
  • Crowd Noise: Noise from large gatherings and events. and those with little experience LOL
• Biological Noise:
  • Biological Interference: Noise caused by living organisms, such as animals or insects.
• White Noise:
  • A type of random noise that contains equal intensity across different frequencies. Often used to mask other sounds.
• Pink Noise:
  • Similar to white noise but with lower intensity at higher frequencies. Used in various applications, including sound masking.
• Brownian Noise:
  • Also known as Brown Noise or Red Noise, it has a spectral density inversely proportional to the frequency squared.
• Impulse Noise:
  • Short bursts of high-intensity sound, such as a gunshot or a hammer strike.
• Thermal Noise:
  • Random electrical noise generated by the motion of electrons in a conductor.
• Mechanical Noise:
  • Noise produced by mechanical vibrations or movements, often found in machinery and equipment.
• Cross-Talk:
  • Unintended transfer of signals between communication channels.
• Quantization Noise:
  • Noise introduced in digital signal processing due to the limited precision of digital representation.
• Aliasing Noise:
  • Noise artifacts that occur in sampled signals when the sampling rate is insufficient.
• 
  
  GPT 3.5 answer
  Debugging electronic noise can be a challenging task, but a systematic approach can help you identify and address the issues causing the noise. Here are some steps you can take to debug electronic noise:
  1. Identify the Source:
     • Begin by identifying the source of the noise. This could be a specific component, a connection, or an external factor like interference from other electronic devices.
  2. Inspect Power Supplies:
     • Check the power supplies for your electronic components. Noise can often be introduced through power lines. Use a scope to examine the power supply voltage and current waveforms for irregularities.
  3. Grounding and Shielding:
     • Ensure proper grounding of your electronic system. Ground loops can introduce unwanted noise. Use proper grounding techniques and consider adding shielding to sensitive components.
  4. Isolate Components:
     • Temporarily isolate components to identify the source of the noise. Disconnect or bypass components one by one and observe the impact on the noise. This can help pinpoint the problematic element.
  5. Use Ferrite Beads:
     • Ferrite beads can be effective in suppressing high-frequency noise on power lines. Place ferrite beads on power and signal lines near the source or affected component.
  6. Add Decoupling Capacitors:
     • Install decoupling capacitors near the power supply pins of integrated circuits. These capacitors can filter out high-frequency noise and stabilize the power supply.
  7. Check for Signal Integrity:
     • Examine the signal integrity on the affected lines using an oscilloscope. Look for unexpected signal distortions or noise spikes.
  8. Use Differential Signaling:
     • For communication lines, consider using differential signaling. This helps reject common-mode noise, improving the signal integrity.
  9. Inspect PCB Layout:
     • Review the layout of your printed circuit board (PCB). A well-designed layout with proper trace routing and ground planes can minimize noise issues.
  10. Eliminate Crosstalk:
      • Check for crosstalk between adjacent traces. Increase the separation between traces or use shielding to reduce the impact of crosstalk.
  11. Upgrade Cables:
      • Low-quality or improperly shielded cables can introduce noise. Consider using high-quality cables with proper shielding.
  12. Filtering Components:
      • Introduce low-pass or band-pass filters where needed to limit the frequency range of signals and reduce noise.
  13. Use Differential Probes:
      • When using an oscilloscope, consider using differential probes to measure signals differentially and reject common-mode noise.
  14. Consult Datasheets:
      • Refer to the datasheets of components for recommended operating conditions, filtering, and grounding guidelines.
  15. External Interference:
      • Investigate if external sources are causing interference. This could include nearby electronic devices, radio frequency interference (RFI), or electromagnetic interference (EMI).
  16. Temperature Effects:
      • Some electronic components may exhibit noise-related issues at certain temperatures. Monitor the system's behavior under different temperature conditions.
  Remember to document your debugging process and make changes one step at a time to observe the impact on the noise. It may also be helpful to consult with colleagues or seek assistance from forums or communities dedicated to electronics and troubleshooting.

--- Updated Feb 2, 2024 ---

Using a Spectrum analyzer on the output of a scope vertical channel or a DSO with FFT is a good way to see noise with different probes.
Common solutions include ferrite chokes and feedthru pins with caps to case.

 

[yefj]

Hello Tony, i want to plug a signal generator to the input of a circuit and output to a scope and create automation to get a closed loop bode plot.
However stability analisys need loop gain not closed loop gain and in real world i cannot open the loop.
What methos do you reccomend to analyse stability using closed loop gain?
Thanks.

 

[D.A.(Tony)Stewart]

You can measure Open Loop Gain in a closed loop. See Verbal Kint's answer. He is a power supply guru that worked at On Semi and is advanced in his design methods with several books he as written on PSU design and design by simplicity.

What is the best way to simulate the open-loop gain of an op-amp in LTspice?

I have been trying to simulate open-loop gain to check the SPICE model in LTspice. From what I could find out so far, there appear to be two main approaches to achieve this. The example in this vi...

electronics.stackexchange.com

also Null method. http://conf.e-jikei.org/ICTSS/2019/...i/IPS04-04(Aoki)/IPS04-04(Aoki)Manuscript.pdf

Also Sigilent, Rigol and others have Bode Plot features as add-ons.

 

[yefj]

Hello Tony,I was told that for loop gainstability we need the open loop gain (and closed loop) .Open loop gain can only be made using simulations.
simulations doesnt take into account parasitics.
for example input parasitic capacitance in opamp intreduces anothe pole and ruins stability.
Sorry for not understanding and answer, is there purely lab measurement method to get loop gain stability?
Thanks.

 

[D.A.(Tony)Stewart]

you measure all load C and parasitic L with RLC meter or estimate and add to simulations.

Open and closed loop Bode plots may be done as I said.
The open loop is closed at DC but intercepted so that AC sweep can be generated and response plot can be made.
but if DC stabilizer bias is not achieved with very low BW then small signal open loop gain(f>BW) cannot be measured

- closed loop stability can be measured by small step response with overshoot at different amplitudes by overshoot to estimate Q and phase margin from Laplace transforms and measure linearity and noise floor. But easiest way is to use DSO with Bode plot option or network analyzer inside loop.