Designer: Maxim Vovenko
This was designed in High School for a club called AVBotz, this work predates my studies of EE at San Jose State University. Reuse Design at your own peral, Im not responsible for anything that happens or gurentee this works. This is only stored for historical record.
This is the Hydrophone Amplifier Code name "Oizys". The code name reflects the absord amount of time figuring out how to make the amplifier and the amount of rivisions that have been trashed. This is the First version of the amplifer wich has been designed based on reasearch and simulations run in LTSpice by Analog Devices. Oziys board is a three stage amplifier and filter combo witch has been tunned to filter out signals below 20khz and above 55khz. The recommended sample rate is above 200khz. The board Consists of three stages each one is powered by an ad8676 dual channel opamp. Dual channel opamps were selected due to the relative little cross talk they have and there ability to process two signals at a time. Stage one is a preamp/decoupling stage witch is required due to the use of piezoelectric Hydrophones. A 1 giga ohm resistor is used to stabalize and prevent saturation of the piezoelectric element. Stage two is an amp stage with the ability to be set to static out-put or variable output by selecting weather you use resistors R2A/R2B or trimpots vr1/vr2 respectively. Stage 3 is an anti-aliasing filter prioritizing speed over atenuation. There is a final passive stage wich offsets the signal by 1.64v using a high pass filter with ground replaced by 1.64v. The amp is to be tuned to function within 0-3.3v. Resources used to build this design are included and so is a BOM.
While the material distrubuted with the mit license I can not and do not take credit for any work done except for the following files: HydrophoneAmpliferCircuit.sch, HydrophoneAmpliferCircuit.brd, README.md, BOM.ods,AmpV0.asc the files listed above are as a result of my work and are as a result covered under MIT License.
Eagle, LTSPICEXVII
-Design is suboptimal, the stages for amplification and signal conditioning should be reversed to prevent clipping -Power Supply instantly fails under any transient voltage spikes. -Improper Crimping may result in damage to power supply due to no reverse polarity protection being present and software engineers not being able to decode wire coloring. -The reference voltage is coupled to the signal producing artifacts in the signal, this needs to be decoupled. -Gain calculations may be off by factor of 10, recalculation required (Symptoms: Signal observed to be in 10mv range instead of 1v).
V1.2 -Updated License -OpenSourced with MIT License -Updated Silkscreens to reflect new state of the project.
V1.1 -Miscillaneous changes -Moved around silkscreen for ease of assembly -DRC Check Cleared -Added OshaPark DRC
V1.0 -Finalized Schematic -Created and finalized board layout and traces. -Created Silk Screens.
V0.3 -Finalized Schematic -Updated Library With Necessary Componets -Organized BRD slightly before building final board
V0.2 -Semi-final design -LTspiceXVII Simulation Files Added -1.6V Rail Created -1.6v Filtering added using 1uf -Identified resistor to replace with pot TODO: -Calculate Amplifier Circuit to add calibration ability -Add C Filtering to 24v rail -Add C Filter 12v -Add C Filter -12v
V0.1.1 -Renamed to "Project OizysAMP" -Updated Capcitors In Filtering circuit to accuratly reflect components being installed -Lost hope in humanity -Wished that power supply filtering was as easy as it is to say power supply filtering
V0.1 Initial Incomplete design -Missing Power supply filtering -missing connectors -Missing Board Design -missing design constraints -Completed amplyfiying circuit -Missing trim pot for tuning amp circuit -Testpoints were added to faciilitate diagnostics.