Hi, does anyone know the theta JC for PS2381-1?

Hi Lilly, 

This product is supported by our team in Japan. 

To best support you on this you will need to submit a Technical Support ticket by going to our support portal from the following link: https://en-support.renesas.com

You will need to sign in with your company email address, and if you don't have an account you will need to register with one. https://www.renesas.com/register 

Best regards, Cindy