5 Test Setup and Procedures

SEE testing was performed on a TPS73801-SEP device mounted on a DEM-SOT223LDO Demonstration Fixture. Power was provided to the device with the V_IN input on the J1 banana connectors using the N6702 precision power supply in a 4-wire configuration. The device was loaded using a chroma load on constant resistance (CR) mode.

The SEE events were monitored using a National Instruments (NI) PXie 5105 (60MS/s and 60MHz of bandwidth) digitizer module. The NI-PXIe Scope card was used to monitor V_OUT and V_IN. The trigger signal was V_OUT using an a window trigger set at ±5% from the nominal output voltage. All equipment was controlled and monitored using a custom-developed LabVIEW™ program (PXI-RadTest) running on a NI-PXIe-8135 Controller. A block diagram of the setup used for SEE testing of the TPS73801-SEP is shown in Figure 5-1. Limits and compliance used during the SEE characterization are shown in Table 5-1. In general, the TPS73801-SEP was tested at room temperature (no external heating applied) where the die temperature was approximately 25°C to 50°C under the load (0 to 1A) conditions used for the testing. A die temperature of 125°C was used for SEL testing and was achieved with a convection heat gun aimed at the die. The die temperature was monitored during the testing using a K-Type thermocouple attached to the heat slug vias of the EVM with thermal compound.

All boards used for SEE testing were fully checked for functionality and dry runs performed to verify that the test system was stable under all bias and load conditions prior to being taken to the TAMU facility. During the heavy-ion testing, the LabView control program powered up the TPS73801-SEP 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).

Figure 5-1 Block Diagram of the Test Setup Used for TPS73801-SEP SEE Characterization

During irradiation the PXIe-5101 scope card continuously monitored the V_OUT and V_IN of the TPS73801-SEP, and any deviation of ±5% of the nominal voltage triggering a capture.

During a trigger event, the digital scope card captured 40k samples (the card was continuously digitizing so when triggered, a predefined 20% of the samples that preceded the event were stored). The NI scope cards captured events lasting up to 2ms (40k samples at 20MS/s). In addition to monitoring the voltage levels of the scope cards (PXI), the current on the V_IN pin was also monitored during each test to monitor for any SEL event. No sudden increases in current were observed (outside of normal fluctuations) on any of the test runs indicated that no SEL events occurred.