I would like to understand how to assess the size of a ST product (STM32F378CC http://www.st.com/content/st_com/en/products/microcontrollers/stm32-32-bit-arm-cortex-mcus/stm32f3- series / stm32f3x8 / stm32f378cc.html) in a WLCSP package (WLCSP66 - 66-pin, 3.767 x 4.229 mm, 0.4 mm of step of wafer level chip scale).
On Wikipedia I find that "the package must not have an area greater than 1.2 times that of the die and must be a single-die mountable package, the direct area."
So it means that the die size should be estimated equal to area_package / 1.2?
Also the same product may have different die size in different packages?
In the sense that STM32F378CC could be sold in LQFP with different dimensions and UFBGA. For EVERY type of package there are Different designs of the same product and thus Different die sizes?
The WLCSP Technology should not be sinónimo of minimum die size?