RF is large signal array. SRAM is small signal array. SRAM uses bit line differential signalling and hence generally faster than register files.

RF is used when depth of memory is less and width is more. SRAM is used when high depth memory is needed.

But SRAM is faster, but requires MBIST in ASIC. Whereas RF is slower and less dense and it does not require MBIST in asic, it is tested using scan chain.

Bit Cell wise difference: RF bit cell: 8 transistors. Read and write ports are different so no read/write conflict. SRAM bit cell: 6t 1RW. Here same word line and bit lines are used for both read and write operations.

Architecture diff: RF: as read and write ports are diff, so separate decoder logic is required for read and write operations. That means decoder area will be twice compared to SRAM decoder.

Area diff: compare to RF, SRAM area is smaller because of above reasons.

Performance: Compared to SRAM, RF performance will be better because read and write ports are separated.

RF: To write to a RF we need decoder and to read from RF we need multiplexer.

Implementation details:

1. DFF to store bits.
2. decoder for each write port.
3. Mux for each read port.

RF tradeoffs:

1. Very fast (a few gate delays for both read and write).
2. Adding extra ports is straightforward.
3. drawback is it doesn’t scale for large memory sizes. Eg: 32 bit registers need 32x1M to 1 multiplexor and 32x20to1M decoder.

SRAM: SRAM is typically 6T cell. SRAM has lower access time and is faster wehereas DRAM has higher access time and is slower compared to SRAM.

SRAM uses transisotrs and latches while DRAM uses capacitors and very few transistors.

L2/L3 CPU cache units are some general applications of SRAM while DRAM is mostly found as main memory in computers.

SRAM needs a constant power supply, which means it consumes more power. DRAM requires reduced power consumption as the information stored in the capacitor.

With SRAM you will loose data when power is OFF.

Advantages of DRAM:

• cheaper compared to SRAM.
• higher storage capacity. hence it is used to create larger RAM space system.
• It does not require to refresh the memory contents.