Part Number: INA826
Dear E2E team
This is Besson, a electronic engineer from ABB.
we are planning to use INA826 in our Level Measurement project as a pre-amp to face a piezoelectric sensor which will generate a 40us narrow pulse with only 200uVpp amplitude. The equivalent C and R of piezoelectric sensor are 900pF and 30Mohm. The power supply what we used for this project is 3V.
Previously we used opa345 as a pre-amp to achieve 26dB Gain because of low power consumption and low ib, and acceptable slew rate (we want bigger than 1V/us).
When we looked into the details of comparison between opa345 and INA826, we were aware of that the ib is 35nA of INA826 is much bigger than opa345, at the same time, take the 200uVpp signal from sensor into consideration, we worry about if INA826 can handle such lower signal or not, also doubt that if INA826 can provide enough bandwidth to achieve 26dB Gain or not, please help us to comment, many thanks.
By the way, we also looked opa314 as a substitute for better performance than opa345, if there is much better alternatives, please tell us, thanks.
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In reply to Besson:
There is not enough information to answer your questions: what is the input common-mode voltage? Is the input signal at 200uV for 40us and 0uV for 40us around Vcm? If so, the bandwidth of INA826 in the gain of 20 (26dB) is more than enough (BW~250kHz - see below.)
The input signal depends on supply voltage, Gain, reference voltage and Vcm, thus to answer your queestion you must specified Vcm.
For 50mV<Vcm<1.35V, 0.1<Vout<2.85 (see below), which allows input differential signal from -70mV to +67.5mV around Vcm.
Please download the Vout vs Vcm calculator using following link:
Marek Lis, MGTSSr Application EngineerPrecision Analog - TI Tucson
In reply to Marek Lis:
The piezoelectric sensor is differential, and we used 1.5V as Vcm for input common mode voltage for INA826 in Tina, and we can get correct simulation result from Tina.
for the schematics and simulation result, please check the attahced figures.
But we still have concerns about the 35nA ib of INA826, it is much bigger than the current design - opa345.
Based on presented information, could you please tell us any other consideration we should take into account if we want to use INA826 as a pre-amp for this application? thanks.
In reply to kai klaas69:
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