U1c - Cross-point Matrix
Description
The U1c is essentially a switch board - allowing the user to make or break a connection between ‘input’ points to ‘output’ points fitted on the module. Each connection can be set individually to an ‘open’ or ‘closed’ state.
There are 8 ‘input’ connectors (a.k.a. ‘sample’/DUT connectors) and 8 ‘output’ connectors (‘instrument’ connectors). This gives the user a grid of 64 possible connections, fully-configurable per each single connection. See illustration below.
Therefore the U1c can: * Rotate / sweep across multiple sample points with single source & measurement instruments * Fan out an instrument with limited connections to multiple samples - simultaneously or sequentially * Link samples - short multiple samples together * Fix non-stimulated sample locations to an external bias or GND.
The U1c is especially designed to work with delicate sensitive samples. In general, switching hardware may introduce transient voltage spikes and charge injections during switching, and DC leakage currents. The U1c is designed to minimize such interference and is fitted with RC filters on all external connectors. It is also recommended to use the U1c module together with the stand-alone Matrix Module (matrix rack), which adds further filtering.
Particular attention was given to protecting the ‘sample’ contacts, hence a tighter filtering was applied to the sample connectors. Additionally, sample-side connections are kept by default at GND via a weak pull-down to prevent charge accumulation. These safeties make the module not symmetrical - the ‘sample’ and ‘instrument’ connectors are not equivalent. Therefore the U1c is not suitable for transient measurements, but is intended for steady-state measurements.
The U1c is configured through a configuration file. This is a .csv file containing an 8x8 matrix of binary values, representing the state of each sample-instrument connection. The file can be uploaded via the functions given in the U1c Python package. It can be edited on the host PC outside the Python environment or uploaded and edited from the Python environment.
Specifications
| Parameter | Value | Units | Conditions |
|---|---|---|---|
| Static Characteristics | |||
| Analog Signal Range | ±15 | V | Range for sample- and instrument-levels |
| Roff | 2 T | Ω | Sample connector to instrument connector |
| Ron | 100 | Ω | Sample connector to instrument connector |
| C sample-instrument | >1 | pF | For any sample from each instrument in the off state |
| C sample-sample | 5 | pF | Typical, for any sample from each other sample | Dynamic Characteristics |
| Voltage Spike at Switching | 20mV | mV | At ±15V supply (default constrauction) |
| Switching Rate | |||