Macros are intellectual properties(IP) that you can use in design. These IPs have been designed by some other analog team, which can be used in the floor plan stage of the design For example, PLL, memories, processor, etc.
Type of Macros
Hard macros are also known as Block. Hard macros always come in terms of hardware IPs, ex. Memory. The functionality of macros is already defined, and we can’t change anything inside it. We knew only the timing information, not the functional information.
Hard macros are defined in LEF or GDS II(Graphic Data System) files.
Soft Macros are defined to Synthesize RTL and these are developed in one hardware description language like systemVerilog or VHDL. It can edit before going to a later stage, which means soft macros are more flexible than hard Marcos. It knew timing information and also functional information.
They are unpredictable in area, timing, and power.
Firm macros are in netlist format. They are optimized for performance, area, and power using a specific technology node. It is more flexible and portable than hard macros.|
It is more predictive of performance and area than soft macros.