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I was browsing On-Semi just looking around when I ran across the NLS457. I hit Google and Bing and after trying multiple search terms have came up with 0 hits would answer my question.

The weird part is that I can not find anything even mentioning it, wither at On-Semi or via search engines. I can't believe that they would go through efforts to design, make and sell a chip that has no purpose. It's a new chip(2018) in a small package and so might be useful in a modern device of some kind, I just don't have a clue what it could be.

It takes the output of two AND gates, each of which has an inverted input and feeds it to an OR gate. It looks like something that might clock related, but in that case I would have thought Schmidt trigger inputs would have helped it's usefulness.

It's most likely something real obvious, but all of my schooling was over 25 years ago, most of which was not working in electronics. I'm getting the feeling that I'm going to be feeling rather stupid after it is pointed out to me.

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First of all, never feel stupid because you don't know what a component is used for. Most components are actually pretty fairly specific.

Looking through the speeds in that datasheet: it's unlikely this is modern technology. Feels like 1980's "low-voltage high speed logic", like 74LVCxxx.

  • It's quite possible a high-volume customer came to ON Semi (or whatever they were called at the time) and said, hey,

    I've got this device all built up, and it's been certified for all this stuff, but now in the final pre-production tests we figured out that our interrupt pin shouldn't just be an OR of all inputs, but this complex function. Recertifying after complex modification will kill our DoD contract soooooo could you build that logic for us?
    We'll by a million of them, but you need to guarantee that there's capacity for another million.

And then ON Semi went on and produced 2 million and sold them for $10 a piece. Now, they're sitting on the remainder and decided to sell them as product.

  • Or, that's a part to some old digital bus that's been lost to time ("If BUS 1 TRANSMIT READY is high and BUS 1 RECEIVE READY is high OR BUS 2..."); maybe some bus arbiter, or maybe just a "OR" gate operating on differential lines.
  • Or, that's really just a kind of "oring" multiplexer: with input B and D a microcontroller can select which inputs get ORed into the output
  • Or, this is an ancient "all in one" logical gate, where external connection to high or low or actual inputs makes the gate useful.
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    \$\begingroup\$ The specs look exactly like low-voltage CMOS (LVC1G/NL17SZ). \$\endgroup\$
    – CL.
    Nov 10, 2019 at 11:54
  • \$\begingroup\$ @CL. yep, I should replace the LS by LVC, gimme a second. Done. \$\endgroup\$ Nov 10, 2019 at 11:57
  • \$\begingroup\$ The 5V tolerant inputs is also interesting; power domain crossing made simple (another family that did this was 74LCX). \$\endgroup\$ Nov 10, 2019 at 12:11
  • \$\begingroup\$ The only reason I called it new was that the Datasheet has a date of 2018 with a 0 rev. On-Semi is a Motorola spinoff. Their HQ is less than 3 miles from me, in the center of what was once a major Motorola fab center. As a matter of fact, the house I live in was built in the 50's as part of an employee housing project. \$\endgroup\$
    – GB - AE7OO
    Nov 10, 2019 at 15:21
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Have a look at the NL7SZ57/(SN)74LVC1G57, a "configurable multi-function gate":

SN74LVC1G57 Functional Diagram

If you keep some input(s) constant, you get several possible logic gates from how the output reacts to the other inputs. Its datasheet says:

The user can choose the logic functions AND, OR, NAND, NOR, XNOR, inverter and buffer.

The NLS457 has four inputs. However, there are so many symmetries that the number of logic functions is not actually larger:

A=0, B=0, C=0: buffer
A=1, B=1, D=1: inverter
A=0, B=0: AND with one inverted input; NOR with one inverted input
A=0, C=0: OR
A=0, D=1: OR with one inverted input; NAND with one inverted input
B=1, D=1: NOR
A=D, B=C: XOR

And the NLS457 lacks Schmitt triggers. Apparently, this device is not meant to be universally usable, and, as the description "special function logic gate" implies, it was probably designed for a specific application for a specific customer, and is sold publicly only because "why not".

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  • \$\begingroup\$ ah nice, nearly synchronously posting answers that agree but highlight different aspects. Have my upvote :) \$\endgroup\$ Nov 10, 2019 at 11:51
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    \$\begingroup\$ You can even make an XOR (tie input A to D and B to C). \$\endgroup\$ Nov 10, 2019 at 11:58
  • \$\begingroup\$ Yeah, I saw the variouis x7/x8 multi config chips(as a matter of fact I ordered some of each). The NLS7Z9X which has the same configuration options does have Schmidt trigger inputs \$\endgroup\$
    – GB - AE7OO
    Nov 10, 2019 at 15:08

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