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Andrew Starr, 10/19/2012 05:06 pm

Lab Journal

20 Oct, 2012 - Tunnelling Current Amplifier simulation

The tunnelling current amplifier is an example of a transimpedance amplifier: it converts a current input into a voltage output. This amplifier is a critical circuit in the microscope, so I have taken advantage of available electronic simulation software to test and tune the design before committing to a PCB.

Bandwidth vs noise

In a transimpedance amplifier there is an unavoidable tradeoff between the bandwidth of the amplifier response and its output noise.

Simple_transimpedance_amp.jpg (92.6 kB) Andrew Starr, 10/19/2012 10:17 pm

Composite_transimpedance_amp.jpg (145.4 kB) Andrew Starr, 10/19/2012 11:30 pm

tca-simple-response.jpg (60.7 kB) Andrew Starr, 10/21/2012 06:37 pm

tca-simple-noise.jpg (52.6 kB) Andrew Starr, 10/21/2012 06:37 pm

tca-composite-response.jpg (58.4 kB) Andrew Starr, 10/21/2012 06:37 pm

tca-composite-noise.jpg (53 kB) Andrew Starr, 10/21/2012 06:37 pm

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