AnsweredAssumed Answered

summing amplifier

Question asked by Christian.S.B. on Apr 10, 2011
Latest reply on Apr 12, 2011 by Reemo


Due to my Bachelor thesis in physics at the Department of Applied Solid-state Physics at the Ruhr-Universität-Bochum (Germany) I have to do capacity-voltage-measurements at Schottky-Diodes.
In this context I intend to use an analog amplifier. Since there is such an enourmous diversity of products it would be great if you could give me some proposal for possible amplifiers.


The amplifier should be used for the following application:
I aim to use an amplifier that adds a DC- and an AC-voltage coming from the reference outputs of a LockIn-amplifier. This AC-voltage with DC offset will be connected with the device under test (DUT)  and the resulting current should be measured with the LockIn-amplifier.


Therefore i want to buy a summing amplifier that should perform the following specifications:
- Adding an DC- and an AC-voltage
- Dividing the AC-voltage through 100
- Amplification of the DC-voltage with factor 1
- DC-voltage in: 0..+-10V
- AC-voltage in: 0..5V (rms)
- Frequency: 0..100kHz
- The current that flows through the amplifier and the DUT and should be measured is about 50fA..0.3mA and is usually about nA.
- Low noise
- Low distortion


It is important, that the amplifier has as few as possible distortion and noise.
Do you have suitable integrated summing amplifiers?


I would be very greatful if you could help me.