What's the difference between 24AA1025, 24FC1025 and 24LC1025

Question

24AA1025: operates from 1.7V - 5.5V, 400kHz, $2.37

24FC1025: operates from 2.5V - 5.5V, 1 MHz, $2.37

24LC1025: operates from 2.5V - 5.5V, 400kHz, $2.37

See here.

24AA1025 is unique, because of the lower operating range. What I don't understand is why Microchip produce both 24FC1025 and 24LC1025 at the same price with different maximum clock frequencies. Why not just make one? Am I missing something?

Answer 1

It seems clear to me. The FC component has a higher clock frequency, but it also has a lower maximum operating temperature. The LC extends this maximum operating temperature, but at the cost of some of the clock frequency.

That gives you the choice of either high temperature, or high clock frequency.

Answer 2

The standby current is much lower for the 24LC1025 (100 nA vs 5 uA). That would be important for low-power applications where the faster speed isn't required.

Answer 3

I've always been amazed at the number of different parts Microchip make, however the 'same price' thing may differ as quantities increase. It may also be the case that a new, faster part is introduced at a premium price, and at some point the products both use the new die, but both numbers are retained to avoid changing customers ordering/parts lists etc. I've not looked at the data but there may also be some other subtle spec differences, like standby or operating power draw. Looking at the LC/FC256 data I have to hand, the LC is avaialble in automotive temp range, the FC is not.