Best package(s) for basic logic

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Douglas Beeson 12 years ago

Hi all,

So my audio gate circuit with has advanced, and now has both voltage-driven and current-driven zero-cross detection elements. To bring them all together, I need to use some good old boolean logic which I have never actually done in hardware. In boolean notation, I need ((A and B) OR (not A and B)), plus one D-type flip flop.

I am loathe to take up space on my PCB with quad-gate chips when I only need one each of 2-gate AND, 2-gate AND with one inverter and one OR.

I have seen multifunction chips like these :

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Money is not the issue; it's space and a certain sense of economy.

What do you all recommend?

Thanks,

doug

Douglas Beeson

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John Larkin 12 years ago

Isn't that just B ?

John Larkin Highland Technology Inc www.highlandtechnology.com jlarkin at highlandtechnology dot com Precision electronic instrumentation

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Jim Thompson 12 years ago

...Jim Thompson

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Douglas Beeson 12 years ago

ven and current-driven zero-cross detection elements. To bring them all tog ether, I need to use some good old boolean logic which I have never actuall y done in hardware. In boolean notation, I need ((A and B) OR (not A and B) ), plus one D-type flip flop.

Yeah, definitely "duh" on my part. I meant:

AB + /AC

need one each of 2-gate AND, 2-gate AND with one inverter and one OR.

mlink/sn74lvc1g97.pdf

Douglas Beeson

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Randy Day 12 years ago

[snip]

Just off the top of my head, couldn't you implement that with a single Quad NAND?

One gate (inputs connected) inverts A, two gates act as AND gates, the inverters on the outputs convert the 4th gate to an OR.

Or is my boolean logic rusty? Damn I wish I had Andy's ASCII Art on this 'puter.

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John Larkin 12 years ago

That's a mux: FSA3157. Costs us 9 cents.

John Larkin Highland Technology Inc www.highlandtechnology.com jlarkin at highlandtechnology dot com Precision electronic instrumentation

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Douglas Beeson 12 years ago

Yup, looks exactly like what I need. Thanks, John!

Douglas Beeson

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Phil Hobbs 12 years ago

Put B and C into the inputs of a 2->1 mux, and use A to run the switch.

Cheers

Phil Hobbs

Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC Optics, Electro-optics, Photonics, Analog Electronics 160 North State Road #203 Briarcliff Manor NY 10510 hobbs at electrooptical dot net http://electrooptical.net

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Douglas Beeson 12 years ago

Thank you, Phil. John Larkin suggested the FSA3157 and it looks like just the trick.

doug

Douglas Beeson

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Phil Hobbs 12 years ago

I saw that after I posted. I often take John's advice as well.

Cheers

Phil Hobbs

Dr Philip C D Hobbs Principal Consultant ElectroOptical Innovations LLC Optics, Electro-optics, Photonics, Analog Electronics 160 North State Road #203 Briarcliff Manor NY 10510 hobbs at electrooptical dot net http://electrooptical.net

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John Larkin 12 years ago

The FSA is actually an analog multiplexer. The "bus switch" type mux's are cheap and fast compared to things sold as official analog multiplexers.

John Larkin Highland Technology Inc www.highlandtechnology.com jlarkin at highlandtechnology dot com Precision electronic instrumentation

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Maynard A. Philbrook Jr. 12 years ago

I ran across something today at work that is a zero cross detector using a 74xxxx14 hex inverter and a 74xxxx74 D flop. jamie

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Best package(s) for basic logic

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