Getting Started with the Switch Card
Electrical connections to the switch card
- Plug in the source measurement unit (SMU), LCR meter (LCR) and ammeter (AM) according to the figure below.
- Plug in the USB connector. The switch card should power up automatically.
Manual controls of the switch card:
- The LED display should show '---' which indicates that all channels are shorted to GND.
- The two central control sticks allow to change the open channel. The default visualisation mode is the octal numeral system, i.e. the channel numbering runs from '000' to '777'. See figure below.
First tests of the card
- To test the functionality of all the MUXes, you can measure the capacitance at 1kHz and 0V bias. This can be done anywhere, e.g. on a table.
- The result should be a step like structure with 3 periods of 8, similar to the figure below. Average capacitance should be somewhere around 120pF.
- If you see a step structure but values well below 100 pF the measurement frequency is too high.
- If you see a step structure but values well below 100 pF for some channels, most likely one of the MUXes is not working correctly. The structure of the capacitance results can tell you which one. It is likely that the MUX is either broken or, if an early version of the card is used, that one of the pull-up resistors on the legs of the switches (bottom side to the MUX) is not soldered correctly.
- If you see values well below 1 pF, you are most likely creating aground loop somewhere outside of the setup or, if an early version of the board is used, resistor R579 is not removed.
Mechanical Integration
Integration with the mounting frame:
- The pogo pins require quite some weight to be fully compressed. The pressure should be uniformly distributed throughout the sensor area. A mechanical frame with an array of (electrically isolating) standoffs is used for this.
- Mount the probe card on the frame. Make sure the number of standoffs is sufficient and they are uniformly distributed.
- Mount the switch card.
- Mount the system to the platen of your probe station.
Getting Started with the Probe Card
Electrical connections to the probe card:
- Plug in a manual manipulator to the LEMO connector on the back of the probecard.
- Bring the HV to the chuck. You can use the screw terminal on the HV area of the probe card (rear left on the bottom side). You can also solder a triax connector to this region if required.
Further tests of the card:
Understanding the Electrical Circuit
Alignment