SMU gang function

[wei-smart]

Dear All,

Is there any plan to deliver standardized API for SMU gang channels.

Normally, customer can configure how many channels will be ganged, then all ganged channels can adjust voltage synchronized. (what even use one remote sense as “Master” or use averaged sensed voltage).

Thanks for your help a lot.

[wei-smart]

[santo_13]

I don't think NI has a plan to provide ganged functions at the driver/hardware level for SMUs. It is up to the user to implement it properly in the application layer.

I have done such merging on 416x SMUs, be careful of all that can go wrong, if the load will vary, the CH1 SMU might try force current into the CH0. In your example, the load is constant and hence no problem, but in a scenario where you test semiconductor DUT, it will not be constant.

For load current measurement, you would need to sum up the current from both SMUs (CH1 will always be positive and CH2 will be negative unless the load is above the source current limit of CH0)

There is a hardware limit on the current from each channel and current for the whole board, you can't exceed those.

Also, take into consideration the source and measure the accuracy of SMUs.

https://knowledge.ni.com/KnowledgeArticleDetails?id=kA03q000000x22lCAA&l=en-US

[santo_13]

Update: Recently, NI has introduced the merged channels feature at the driver and instrument level (note this is only on specific models - PXIe4147)

https://www.ni.com/docs/en-US/bundle/ni-dcpower/page/ni_dc_power_supplies_help/increasing-smu-current-merging-channels.html#guid-987c767e-fa22-4bd5-b33f-06e76c021949 

https://www.ni.com/docs/en-US/bundle/ni-dcpower/page/ni_dc_power_supplies_help/merged-channels.html