TPS82130: Tolerance to ionizing radiation

Hi Tom,

Flash stores data by storing electronic charge in floating gate memory cells. If the floating gates are hit by X-ray, the charge may leak. When the leakage exceeds a certain degree, the bit will be erased. So in theory, there is always a risk exposing flash under X-ray. Whether the flash will corrupt depends on the amount of radiation it receives, which is affected by exposure time, beam current and voltage potential of the X-ray machine. X-ray machines are different so it is difficult for TI to specify a safety threshold.

However, the customer can conduct a test: if the device can survive X-ray exposure for 10x longer time than real application case, the device should be OK. The customer should avoid inspecting or leaving the board under X-ray for extended time period.

Also, the X-ray machine usually generates a relatively wide spectrum but only a certain frequency is used to develop the image. A technique that applies a thin Zinc film to filter output unnecessary frequencies can be used to reduce X-ray exposure of the board. Please refer to Richard C. Blish II, Susan X. Li, and David Lehtonen, Filter Optimization for X-Ray Inspection of Surface-Mounted ICs, IEEE Transactions on Device And Materials Reliability, vol.2, No.4, December 2002.

Best regards,
Omar