Solution
While capable of temporarily producing drive strengths of over the specified 32 mA maximum, PXIe-657x risks two main failure modes when operated beyond specifications:DC Accuracy and Long-Term Reliability.
DC Accuracy
With a higher DC driver output current, the customer should expect higher deviations from the nominal voltage. The nominal voltage must account for the PXIe-657x internal parasitic resistances of ~ 1 Ω in addition to any cable or fixture resistances in the customer's setup.
Note: the PXIe-657x DC Accuracy driver specification of +/- 15 mV is warranted for a 1 MΩ load termination only.
Long-Term Reliability
Due to overheating on the pin electronics backend, there are long-term reliability concerns for higher DC drive currents.To include the PXIe-657x operation in different corner cases, the specification was set to a maximum DC Drive Current of +/- 32 mA to ensure long-term reliability for our customers. The recommendation is to stay under this 32 mA current limit to ensure the module’s specified performance and long-term reliability under different operating conditions.