Part Number: TLV3404
We are working an a design with a piezo element. This piezo element (long cable) generate an output when it is triggered (e.g. by a car driving over it). The piezo output has to be digitalized such that it can server as an interrupt to a processor. For this I want to use 2 opamps.
The first opamp amplifies the piezo signal and the second opamp is a comparator. The output of the 2nd opamp is fed into a processor. For the opamp design the following is considered
As the piezo cable is a separate sensor I am not sure how the input bias current path could run. Have a quick sketch drawn below. As I am not an opamp designer I hope you can give me some guidance or tips how I could make this design work
Thanks a lot!
In reply to kai klaas69:
Not using the OPA348 for the simple reason that it does not come in a DIP package. I am only used to work with breadboard before creating a PCB protoboard.
(maybe silly question but are there other ways to test non-DIP packages?)
The TLC272 comes in a PDIP package so that is one I can use to test.
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In reply to Jeroen van Bussel:
Received the adapters and got the circuit working with the OPA348 and the TLV3012. The detection of the piezo signal goes very well.Have connected the output directly to a micro processor and signal is received.
However there is one issue which I have not found a solution for. After measuring on the oscilloscoop I found out that when the output (comparator) goes from LOW to HIGH the first 50 usecs the signal bounces a couple of times.Not sure what the best measurements are to eliminate this?
you could add some hysteresis:
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