Fuse usage

[c70206150]

this question is regarding the use of fuses in SoC or ASIC's
I have noticed that in newer designs, the number of fuse bits are quite high. As high as 20Kb for example
I can understand fuse values being used for ramp repair etc. but I see a lot of bits being used for IP configuration (e.g. to enable a feature or disable).
Normally, such configurations can be done using configuration and control registers.

So, the question is what is the reason why the new designs have such a large number of fuse bits?

 

[rca]

fuse can be used to differentiate product from the same die.
fuse can be used to store life cycle state....

 

[dick_freebird]

At 20K bits, what you likely have is a fuse PROM bank
(like for boot code?). Trim bits for analog, which is a common
use for fuses, would need far fewer.

It was difficult to do on-chip fuse programming back in the
older CMOS generations, but now programming-switch
size for current has gone way up, while neck current to
fuse minimum polycide or metal has gone way down, so
fuses have become net-area and -reliability winners again.
Back at the 250nm and 500nm generations I could only
get enough current-to-blow into a fuse that sat across a
pad-pair (generally, one of them would be GND and the
rest, used to control CMOS switches in analog blocks).

 

[ThisIsNotSam]

fuse can be used to differentiate product from the same die.

this