Test campaign on LVDS
In 2011, the Onboard Computer and Data Handling section has performed a lab test campaign on LVDS components in order to characterize them in a cross-strapping configuration used in On Board Computer units. LVDS drivers (’31) and receivers (’32) from three different manufactures (National Semiconductor, STm and Aeroflex) have been tested.
For a type of devices, a dedicated evaluation board has also been designed and developed with the support of the TEC-TCE section. A particular attention has been dedicated to the Aeroflex components as they are used in several flight units that are approaching the launch date; detailed test plans, test procedures, intermediate dry-run tests and the final test report have been produced for the Aeroflex 5Vdc UT54LVDS032 and 3.3Vdc UT54LVDS032LV components.
The first test that has been executed was presence of oscillation at the power up: no spontaneous oscillations at the output of the undriven ports of the LVDS receiver (5Vdc and 3.3Vdc version) at the power up or during normal operative modes have been detected in all the foreseen test sequences.
The second test was to measure the noise sensitivity using two different methods: a bulk current injection method and a capacitive coupling method.
In both test methods, a success criteria of 30mV as amplitude of the injected input signal that produces an oscillation at the output has been considered. This value considers a margin of 20mV when related to the value present in the Aeroflex Datasheet (10mV). The second test has also been successfully concluded.