OPA2192: OPA2291 outout 3.6V square wave without input signal

Hi,

your schematic is very hard to decipher. Can you please redraw it?

Kai

Hi user4577981,

I think that this is your circuit. Please let us know.

There are issues with the schematic, and the DC bias is not configured properly.

/cfs-file/__key/communityserver-discussions-components-files/14/OPA192-E2E-05222020.TSC

Best,

Raymond

thank you, sir, I will check it with my colleague

hi sir

shall I get your point exactly, how many issues are there in this circuit? I found that the power should be higher than 4.5V, and 3.3V could not be used, right?

other issues are?

Hi user4577981,

Please confirm the converted circuit is actual circuit you had posted. It is hard to visualize what you had. 

I need to know your hydrophone's input range and output load. Yes, the minimum single voltage rail has to be 4.5V minimum. 

Best,

Raymond

yes the circuit you post is right, the hydrophone's input are two mics sensering the heart sound. output are connected to CSR chip, which are mics input. thank you! 

Hi user4577981,

Your DC gain is so high (1001) and voltage rail is so narrow. I need to know your actual input signal level. Is it in microvolt range or mV range? With 1mV input  AC signal, your output is already over 1V. With necessary DC biased for the circuit because of the single 5V rail, I need to know your input signal range. 

Can you use dual supply voltage rails? Say bias the negative voltage rail with LM7705? What BW are you trying to get out of this circuit?

Best,

Raymond

Hi user4577981,

I quickly put together a working version, see the attached simulation. However, it is not optimized in any way, since I have a little information about your design requirements. At least you are able to simulate the circuit.  LM7705 will generate -0.233V negative voltage rail with +5V DC input. The gain of the circuit is still too high for the required voltage supply rails.  

In addition, hydrophone normally required to drive a speaker or capacitive load. 

/cfs-file/__key/communityserver-discussions-components-files/14/OPA192-Hydrophone-05272020.TSC

Best,

Raymond

Hi Raymond

My input signal level is within microvolt level, our hardware system only have a 3.3V power rail, a higher or dual supply power rail will have a big impact on the system power consumption 

the input frequence is between 40HZ to 500HZ

based on this situation ,what DC gain may be proper for our usage you think, thank you, if we can change to another  moundel with 3.3V power supply? thank you  

Hi user4577981,

I thought that you understood that the minimum voltage is 4.5V for a single voltage supply. You need to select another Op Amp for the application. 

http://www.ti.com/amplifier-circuit/op-amps/precision/overview.html

Best,

Raymond

Hi Raymond

yes, in my opinion, OPA2192 is not suitable for this system, but what is funny is that this solution comes from WuHan University, they made it for us, and its team said that it works well, haha  

thank you Raimond, thanks for your work, we will consider to change power rail or amplifier, and I learnt a lot from you. thank you.

Hi user4577981,

OPA192 is very capable and high performance IC, and is one of best seller at TI. But it is not the best options for lower voltage and single voltage supply rail precision op amp.. You mentioned that you are concerned about the current consumption as well. 

If you tell me your application and design requirements, I will find something for you on Monday. Is this battery operated hydrophone application?

Best,

Raymond

Hi Raymond

thanks.

yes, it's a li-ion battery powered application, and at present, we give a 3.3V power to the mic pre-amplification circuit, the measured signal is within 100HZ-500HZ frequence, microvolt level,

output is connected to the AD circuit of cpu.

hi Raymond

I use TI tool designed a filter as attachment, please help me check thank you, it's just a filter

filter-design-report-TLV2711.pdf

Hi user4577981,

I need to get back to you. Somehow I am unable to locate the TLV2711 PSpice model. 

FYI, please create a new thread in the future under E2E. The link tends to be organized under a single inquiry. 

Best,

Raymond

Hi user4577981,

What was the program that you generated the 4-pole bandpass filter?

For the most part the design report is correct. However, I was not able to match the magnitude dB and phase response exactly. Enclosed is the simulation for the filter design, and you can check it out yourself. I only use the simulation tool these days. Please let me know if you have questions. 

/cfs-file/__key/communityserver-discussions-components-files/14/TLV2211_5F00_TLV2711_5F00_-BandPass-Filter-06020202.TSC

Best,

Raymond