What is minimum rank required to get into top institutes like IIT'S and IISc or PSUs?
This depends on the institute and the program that a candidate applied to.Generally students with a rank upto 500 in GATE are in a good position to do well in the technical interview at the IITs/IISc /PSU however several top institutes and PSUs are flexible on the rank requirement. Many student with lower rank have secured admission job at top institute/ PSU based on their technical interview Performance.
I hope it will helpful
Good luck