OCTOPUX - automated setup for testing superconductor circuits
Basic technical features
- 32, 64 or 128 universal I/O channels for precise analog measurements and fast digital testing
- Each channel has low noise DC bias outputs with 4 programmable ranges from +-200 uA to +-200 mA, with
16-bit resolution at each range.
- Truly differential measurements between any pair of channels with accuracy 0.5 uV P-P in 4 kHz bandwidth
- Fast multi-channel pattern analysis at data acquisition rate of up to 2 MS/s, with
noise limited sensitivity of 10 uV P-P at 1 MS/s rate
History
OCTOPUX is a universal multi-channel system for testing
superconductor circuits. It is being used worldwide since 1997
by leading groups dealing with superconductor circuit design and
technology. The reason for this is simple - OCTOPUX system
outperforms all other commercially available setups by robust
performance and operation versatility. But the most important feature of OCTOPUX
system is its compatibility with rigorous requirements imposed by superconductor
chip testing, which results from extremely high sensitivity of superconductor circuits
to external electromagnetic interference and the quality of used current sources.
Whether being used for chip design functionality testing or for
fabrication chip screening, OCTOPUX will always provide you
with the best and the most effective solution. Due to completely
automated control, OCTOPUX can implement sophisticated
measuring protocols, which is vitally important in volume testing
and characterization of fabrication technology.
OCTOPUX system was developed in close collaboration of engineers and physicists with
more that 30 years of experience in the field of superconductor research and
measurement instrumentation. The system utilizes unique
approaches that ensure minimization of 50/60 Hz power line and
external RF interference from laboratory equipment, computers
and other remote sources.
Applications and functional description
Recent progress in the field of superconductor
electronics, particularly the Rapid Single Flux Quantum (RSFQ)
logic and memory devices, requires adequate testing equipment
that can flexibly accommodate the needs of analog and
digital superconductor circuit designers.
Octopux perfectly satisfies these requirements by utilizing the following technical solutions:
- Hybrid design concept that naturally integrates the fast but less
accurate hardware for digital experiments, and a slow but precise
equipment for analog experiments, allows the user to choose a flexible trade off
between speed and accuracy of measurements
- Sensitive and low noise analog-to-digital converters and sophisticated
built-in algorithms optimized for typical RSFQ signal encodings
make it possible to facilitate high-speed data acquisition and
logic analysis
- Matlab environment provides for convenient hardware control combined with
the ease of programming of sophisticated measurement scripts. All measured results are
immediately available to user in the form of Malab variables, which significantly simplifies
the subsequent data processing and visualization.
Advanced features
- Truly differential precision analog measurements
- Digital test pattern generation and analysis
- DC biasing with controlled rise/fall time simultaneously at several bias lines
- Monitoring actual values of applied DC bias currents
- Automated measurement of Ic for shunted and non-shunted junctions
- Extraction of on-chip resistances and inductances
- Finding multidimensional parametric windows for arbitrary functional tests
- Real-time virtual oscilloscope with possibility of power spectrum analysis
- Self-calibration and self-diagnostics functions
- Direct control of hardware from Matlab
