find equivalent of SN74LS161 DIP16 => to SOIC16

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Kayumba
Posts: 113
Joined: Sun Mar 01, 2020 2:36 am

find equivalent of SN74LS161 DIP16 => to SOIC16

Post by Kayumba » Tue Dec 01, 2020 1:09 pm

Hi,

I'am looking for to remplace my 4bit counter chip SN74LS161 (dip one) by SOIC one.
Can someone help me to find equivalent, please.

Exactly with "LS" I can not find it with assembly PCB service.
But 74HC161D, yes.

Will it be exactly the same?

Thank you

soniccd123
Posts: 26
Joined: Sat Jun 27, 2020 12:01 pm

Re: find equivalent of SN74LS161 DIP16 => to SOIC16

Post by soniccd123 » Wed Dec 02, 2020 11:05 am

Kayumba wrote:
Tue Dec 01, 2020 1:09 pm
Hi,

I'am looking for to remplace my 4bit counter chip SN74LS161 (dip one) by SOIC one.
Can someone help me to find equivalent, please.

Exactly with "LS" I can not find it with assembly PCB service.
But 74HC161D, yes.

Will it be exactly the same?

Thank you
The LS and HC tell the tecnology used to build the chip. Normally this is important to tell the signal activation level which the chip operate and speed. You need to know what the signal level you're going to feed it and what outputs the rest of your circuit is expecting. Normally 5V circuitry from the SNES era and before can be compatible with both from what I know and my experiments. This choice is specilly problematic when trying to interface 3.3V or less logic.

If you look a the 74LS161 datasheet:
Image

And compare to the 74HC161:
Image

You can see that when powered with 4.5V (the LS chip is limited to 4.5V - 5.5V range), the minimum input HIGH voltage of the LS is 2.0V while the HC one is 3.15V, likewise the max LOW voltage level is 0.7V in the LS and 1.35V in the HC. These can be problematic depending on the voltage levels that you want to interface the chip with. If you look at the datasheets, output levels also vary.

There are other diferences, regarding speed and power levels, but for the SNES era and before, i think these are the most important.

Kayumba
Posts: 113
Joined: Sun Mar 01, 2020 2:36 am

Re: find equivalent of SN74LS161 DIP16 => to SOIC16

Post by Kayumba » Wed Dec 02, 2020 11:25 am

soniccd123 wrote:
Wed Dec 02, 2020 11:05 am
Kayumba wrote:
Tue Dec 01, 2020 1:09 pm
Hi,

I'am looking for to remplace my 4bit counter chip SN74LS161 (dip one) by SOIC one.
Can someone help me to find equivalent, please.

Exactly with "LS" I can not find it with assembly PCB service.
But 74HC161D, yes.

Will it be exactly the same?

Thank you
The LS and HC tell the tecnology used to build the chip. Normally this is important to tell the signal activation level which the chip operate and speed. You need to know what the signal level you're going to feed it and what outputs the rest of your circuit is expecting. Normally 5V circuitry from the SNES era and before can be compatible with both from what I know and my experiments. This choice is specilly problematic when trying to interface 3.3V or less logic.

If you look a the 74LS161 datasheet:
Image

And compare to the 74HC161:
Image

You can see that when powered with 4.5V (the LS chip is limited to 4.5V - 5.5V range), the minimum input HIGH voltage of the LS is 2.0V while the HC one is 3.15V, likewise the max LOW voltage level is 0.7V in the LS and 1.35V in the HC. These can be problematic depending on the voltage levels that you want to interface the chip with. If you look at the datasheets, output levels also vary.

There are other diferences, regarding speed and power levels, but for the SNES era and before, i think these are the most important.
Thanks for answer,

I use DIP16 "LS" chip to do Flip-Flop multirom counter.
What do you think, will it works with "HC" ?
When I order my pcb I can not find 74LS161 SOIC16 chip with assembled service.
Only HC is available.

User avatar
Ben Boldt
Posts: 754
Joined: Tue Mar 22, 2016 8:27 pm
Location: Minnesota, USA

Re: find equivalent of SN74LS161 DIP16 => to SOIC16

Post by Ben Boldt » Wed Dec 02, 2020 11:51 am

Do you have 74HCT161 available? HCT is a good choice if your logic levels feeding into the inputs of the chip are unknown.

Image

Kayumba
Posts: 113
Joined: Sun Mar 01, 2020 2:36 am

Re: find equivalent of SN74LS161 DIP16 => to SOIC16

Post by Kayumba » Wed Dec 02, 2020 12:16 pm

Ben Boldt wrote:
Wed Dec 02, 2020 11:51 am
Do you have 74HCT161 available? HCT is a good choice if your logic levels feeding into the inputs of the chip are unknown.

Image
:(
No, they dont have "HCT"

soniccd123
Posts: 26
Joined: Sat Jun 27, 2020 12:01 pm

Re: find equivalent of SN74LS161 DIP16 => to SOIC16

Post by soniccd123 » Wed Dec 02, 2020 4:31 pm

Kayumba wrote:
Wed Dec 02, 2020 11:25 am
Thanks for answer,

I use DIP16 "LS" chip to do Flip-Flop multirom counter.
What do you think, will it works with "HC" ?
When I order my pcb I can not find 74LS161 SOIC16 chip with assembled service.
Only HC is available.
It really depends on what you're doing, specifically what kind of inputs and outputs you need in that part of your circuit. If you're using 5V logic in the chip inputs and outputs, it should work, but if I were you and had the possibility, I would test it someway before just to be sure, just for the ins and outs to be in the correct ranges needed.

Kayumba
Posts: 113
Joined: Sun Mar 01, 2020 2:36 am

Re: find equivalent of SN74LS161 DIP16 => to SOIC16

Post by Kayumba » Thu Dec 03, 2020 12:59 am

soniccd123 wrote:
Wed Dec 02, 2020 4:31 pm
Kayumba wrote:
Wed Dec 02, 2020 11:25 am
Thanks for answer,

I use DIP16 "LS" chip to do Flip-Flop multirom counter.
What do you think, will it works with "HC" ?
When I order my pcb I can not find 74LS161 SOIC16 chip with assembled service.
Only HC is available.
It really depends on what you're doing, specifically what kind of inputs and outputs you need in that part of your circuit. If you're using 5V logic in the chip inputs and outputs, it should work, but if I were you and had the possibility, I would test it someway before just to be sure, just for the ins and outs to be in the correct ranges needed.
Thanks.
Will order separately 74HC161 and try to do some tests with it.

Kayumba
Posts: 113
Joined: Sun Mar 01, 2020 2:36 am

Re: find equivalent of SN74LS161 DIP16 => to SOIC16

Post by Kayumba » Sun Jan 24, 2021 6:51 pm

I tried, 74HC161 works fine for flip-flop function.
Thanks

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