0
\$\begingroup\$

I need to use a fast decoder to communicate with a SRAM memory, CY7C1041GN. The circuit I need to implement is the circuit suggested in the Example #5 of the document AN2408 .The suggested decoder in this example is obsolete, but I found another, even better, with a smaller Tpd, the model that I found was the SN74LVC1G139, its Tpd is in the range of 0.8ns to 3.6ns using VCC = 5V. The problem with this model is that it does not have active low Enable pin.

I supposed that the work done by the decoders in the example #5 of AN2408, could be done by logic gates, but I didn't find logic gates that are faster than the found decoders.

I searched in many places, I listed many 2x4 decoders at digikey site, I did parametric seach at Texas, Nexperia and OnSemi websites, but I didn't found a model that have a Tpd(propagation delay) as low as 3.6 ns. Does someone know, or has a tip, of a model of decoder with Enable-Low pin that is able to reach these values of Tpd ?

\$\endgroup\$
2
  • \$\begingroup\$ I'm sorry, but we are not supposed to recommend specific products or places to buy them. \$\endgroup\$ Apr 24, 2020 at 15:25
  • \$\begingroup\$ Yes, Eliot Alderson. In addition to the places I mentioned, would you know where I can get information like that? \$\endgroup\$
    – Daniel
    Apr 24, 2020 at 15:36

1 Answer 1

1
\$\begingroup\$

The 74x139 decoder is a common chip, you should be able to easily find them. The 'x' in between the numbers will change depending the logic levels, so pick one that's compatible with your design. (The chip you found is a 1G139, which isn't quite the same thing.)

\$\endgroup\$
2
  • \$\begingroup\$ Yes, Justin. But I didn't find yet one as faster as I need. \$\endgroup\$
    – Daniel
    Apr 27, 2020 at 11:36
  • \$\begingroup\$ I found a good choice. SN74LVC1G29. It is a 2x3, but, maybe, can work \$\endgroup\$
    – Daniel
    Apr 27, 2020 at 13:49

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge that you have read and understand our privacy policy and code of conduct.

Not the answer you're looking for? Browse other questions tagged or ask your own question.