500 kHz / 5 MHz Impedance Analyzer

The Zurich Instruments MFIA is a digital impedance analyzer and precision LCR meter that sets the new standard for impedance measurements in the frequency range from 1 mHz to 500 kHz (extended to 5 MHz when upgraded). The MFIA has a basic accuracy of 0.05% and operates over a measurement range spanning from 1 mΩ to 1 TΩ. It is also characterized by a high measurement repeatability and small temperature drift. Every MFIA comes with the LabOne user interface and with the MFITF Impedance Test Fixture.

With multi-device synchronization (MDS) you can operate multiple MFIAs as a single multi-channel device:

• Operate all instruments from a single LabOne user interface and LabOne API.
• Lock in phase all instrument clocks and oscillators (stable phase relationship).
• Synchronize time stamps and sampling rates for automatic alignment of measurement data.

Front panel interface

The front panel of the MFIA features 1 current signal input, 1 differential voltage input, 1 differential signal output, 2 auxiliary inputs that can work as reference inputs, and 4 auxiliary outputs. Both signal inputs and outputs can be operated in single-ended and differential mode for experiments that require extra noise immunity. The signal ground can be referenced to the instrument ground or to the BNC shield of the signal inputs.

Back panel interface

The back panel offers additional BNC connectors comprising 2 trigger inputs, 2 trigger outputs, and 1 input and 1 output for 10 MHz clock synchronization. Moreover, a SCSI connector offers access to all DIO channels. The units can be operated with standard 90 - 240 V mains supply or by an external 12 V DC power supply (e.g., an external battery pack) to break up ground loops.

High repeatability and fast start-up

Temperature changes of the instrument can severely limit start-up speed and measurement repeatability. The MFIA performs exceptionally well in both aspects, as shown by the start-up drift graph above and by the reactance chart at the bottom of the page. You can start the first measurements after 25 s from turning on the instrument.

Voltage and current measurements

Voltage measurements and current measurements are both supported by the MFIA. The analog front end features variable input impedance as well as AC/DC coupling selection, and the high-frequency analog to digital sampling provides a large oversampling factor. This ensures superior lock-in performance and high signal fidelity for the Scope.

Parametric Sweeper

The Sweeper enables measurement automation by scanning instrument parameters over a defined range with a freely adjustable number of scan steps, linearly or logarithmically. It is also possible to automatically record the frequency dependence as well as the variation of bias voltages or test signal amplitudes. A variety of application modes enable the identification of the optimal settings to obtain the most accurate results in a minimum time without tedious manual tweaking.

The example above shows a frequency sweep from 100 Hz to 5 MHz of a 1-GΩ resistor in a dual-plot representation. The top plot illustrates the absolute value of the impedance |Z| and the resistance Rp. The bottom plot shows how the stray capacitance Cp remains constant at about 30 fF over the entire scan range. A free choice of additional parameters can be visualized at the same time.

Numeric

The Numeric tool displays all measurement values and model parameters in a user-configurable format. Each impedance unit features simultaneous views of the impedance value, the underlying current, the voltage measurements, and the model-derived parameters (L,C,R, etc.).

Plotter and SW Trigger

The Plotter and Software Trigger are tools for the analysis of measurement data and model parameters in the time domain. The Plotter can display multiple data streams continuously. For a window length of 10 s, the time resolution goes down to 10 μs. The Software Trigger captures and displays individual shots based on different internal and external trigger conditions.

The LabOne Plotter displays impedance data continuously. The above plot shows data from a 100-mΩ resistor over 20 minutes. The histogram indicates a standard deviation as small as 6 µΩ.

Confidence Indicator

All measurement data pass a confidence estimation before appearing in the LabOne tools. Whenever the measurement is compromised by suppression, gain error, or compensation error a warning flag is raised to signify that the data might be inaccurate. Depending on the type of warning, suggestions are provided to improve the measurement result.

Compensation Advisor

In order to achieve a high measurement accuracy, parasitic effects caused by the test fixture or cabling between the instrument and the DUT need to be compensated. The LabOne Compensation Advisor provides step-by-step guidance and an efficient workflow to achieve maximum measurement performance. In addition to Short-Open (SO) and Short-Open-Load (SOL) compensation, a variety of alternative compensation schemes are offered. Each compensation step is validated and feedback is provided before data are taken to correct for measurement errors.

The reactance chart presented below indicates the instrument accuracy for given frequency and impedance values. In the wide core area indicated in white, a 0.05% accuracy is specified between 1 mHz and 500 kHz, and 1 Ω and 1 MΩ (with limitations towards higher frequencies). The measurement range extends further with reduced specified accuracy of 0.1% and 1% to cover a measurement range from 10 mΩ to 1 GΩ. Even outside of this range, repeatable measurements are possible but accuracy might drop below 1%.

Measuring high impedances at low frequencies can be particularly challenging when values have to be obtained close to the line frequency. Adequate sample shielding along with a sinc filter and the possibility for battery operation will provide the most accurate results.