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I am in the process of designing a PCB that will drive a piezo transducer that is split into 4 quadrants with a DAC81404. The piezo transducer will move an atomically sharp tip to probe the surface of a specimen whereby a preamp circuit will measure and amplify the tunneling current when the tip gets close to the sample.

The idea is to scan the sample in an X Y pattern to build up a height map of the surface.

My question is will the DAC81404 be adequate to directly drive the piezo transducer or will I need an additional power stage after the DAC? The piezo transducer is a general use 25mm diameter piezo disk used in cheap piezo buzzers. The piezo transducer has a capacitance of 25000pf at 1khz and a resonant impedance of 500ohms. The DAC has an output stage that specifies a load current of 15mA when Avdd is > 5.5v. now I'm not sure if this is the correct spec to be looking at? I know that the faster I drive the piezo the more current it will require. How would I go about calculating ho much current the DAC will need to supply if Avdd is a bipolar 15v supply and I want to do 100hz scanning.

I would like to scan as many points /second as possible but would be happy with even 100hz scanning rate. This is the first design cycle of this thing I'm building so I plan to get it working to some degree and then start refining it.

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  • \$\begingroup\$ What voltage does the piezo element require? It is common to need many tens or hundreds of volts to get the required motion. There are driver devices for camera focussing that have internal voltage boosters as well as the amplifiers to provide the needed voltages. \$\endgroup\$ Commented Jun 25, 2023 at 1:05
  • \$\begingroup\$ You can just say you're making a scanning tunnelling microscope. \$\endgroup\$ Commented Jun 25, 2023 at 1:23
  • \$\begingroup\$ 30V peak to peak \$\endgroup\$ Commented Jun 25, 2023 at 6:32

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