6 Test Setup and Procedures

There were two input supplies used to power the TPS7H502X-SP which provided V_IN and EN. The V_IN for the device was provided via Ch. 3 of an N6705C power module and ranged from 4.5V to 14V for SEL, SEB/SEGR, and SET testing. The EN of the device was driven by an E36311A power supply and was either forced to 0V or 4.5V to enable or disable the device. A NI PXIe-6341 DAQ was used to drive V_SNS and V_COMP. V_LDO had 3 programmable voltages, 4.5V, 5V, or 5.5V and were selected by closing relays to connect to a feedback network on the EVM to select the required V_LDO voltage. Input ranges for the different modes and switching frequencies are shown below. Note that the P_VIN column denotes whether or not P_VIN (the driver stage input) was tied to V_IN or V_LDO.

The primary signal monitored during testing was GATE (OUTH and OUTL tied together on the EVM) and this was done so using a PXIe-5110 triggering using a pulse-width trigger at 20%. The other three signals monitored were REFCAP, V_LDO, and SS which were monitored on their own independent NI PXIe-5172 or NI PXIe-5162 cards. The two signals on the PXIe-5172 triggered on a 3% window, the SS signal triggered off of 500-mV below its nominal value.

All equipment was controlled and monitored using a custom-developed LabVIEW™ program (PXI-RadTest) running on a HP-Z4 desktop computer. The computer communicates with the PXI chassis via an MXI controller and NI PXIe-8381 remote control module.

Equipment Settings and Parameters Used During the Open-Loop SEE Testing of the TPS7H502X-SP shows the connections, limits, and compliance values used during the testing. Figure 6-1 shows a block diagram of the setup used for SEE testing of the TPS7H502X-SP.

Note that only the relay for the correct feedback network was driven by the PXIe-6341 for V_LDO, not the actual V_LDO voltage.

For testing of the TPS7H502X-SP in the flyback configuration V_IN was set to 12V and supplied through Ch. 1 of the N6705C. The input of the power stage was set to 28V and supplied through Ch. 3 of the N6705C. The programmable VLDO was set to 5V. For all flyback configuration testing PVIN was tied to VLDO putting the device in GaN mode. A Chroma E-Load in constant resistance mode was used to load the device with a resistance of 1.25Ω to provide a load of 4A. The primary signals monitored were GATE (the OUTH and OUTL tied together before the transformer) and V_OUT (the DC output after the transformer).

All boards used for SEE testing were fully checked for functionality. Dry runs were also performed to ensure that the test system was stable under all bias and load conditions prior to being taken to the test facilities. During the heavy-ion testing, the LabVIEW control program powered up the TPS7H502X-SP device and set the external sourcing and monitoring functions of the external equipment. After functionality and stability was confirmed, the beam shutter was opened to expose the device to the heavy-ion beam. The shutter remained open until the target fluence was achieved (determined by external detectors and counters). During irradiation, the NI scope cards continuously monitored the signals. When the output exceeded the pre-defined pulse-width or window trigger, a data capture was initiated. No sudden increases in current were observed (outside of normal fluctuations) on any of the test runs and indicated that no SEL or SEB/SEGR events occurred during any of the tests.