According to the ElanSC520 datasheet #22003:
For -133AC
"133" = 133 MHz
"A" = 388-pin plastic ball grid array
"C" = commercial temperature range T = 0 °C to +85 °C where T = case temperature
-133AD is not in the datasheet, or the revised datasheet #22003B. Logically, the "D" must refer to another operational temperature range.
