S29AL008J55TFIR10 (TS048 package) has a junction to ambient thermal resistance (Theta JA or θja) of 40 °C/W.
We do not provide theta JC and theta JB thermal resistance values for our flash products. We usually give psi JT and theta JA parameters which provides a meaningful method to predict junction temperature in plastic package devices.
The psi JT value is 17 C/W.
You can find this value (theta JA and psi JT) in the device qualification report page 2 available at:
Also, for your reference, please find our application note "Thermal Considerations and Parameters" available at:
It explains why theta JC and theta JB values are not good approximations for plastic packages. I hope this application note is helpful for you.