Thank you for contacting Cypress Semiconductor.
We do not provide the values for thermal resistance to base and thermal resistance to case for our flash devices.
However, I can tell you the Theta JA and Psi JT values which can be used to calculate the value for maximum operating junction temperature.
The Theta JA and Psi JT values for S29GL256P11FFIV20 (LAA064 - 64 ball FBGA) are -
- Theta JA - 39 °C/W
- Psi JT - 11 °C/W
The following application mentions the formula for calculating maximum operating junction temperature value - https://www.cypress.com/documentation/application-notes/an201006-thermal-considerations-and-parameters
Please let me know if you have any further queries.