Retention Flop basics

[mehboobali]

1. What is Retention Flops?
2. How it differ from the simple flip flop?
3. Where they are widely used and why?
4. How the retention flops are related to power?
5. Is the cross-coupled inverter which stores data is itself the retention flop.?

Can anyone please explain it clearly.

Thanks in advance.

 

[rca]

1- retention flop has two power supplies, one could be switch-off.
2- when the functional power supply is of the second power supply will preserve the flop contains.
3- there are used when you want to switch off std-cell island, it is to reduce the leakage power.
4- see below.
5- no idea.

 

[bright8848]

I think cross-coupled inverter seems like a simple latch, retention flop is special flop for low power design.