The SN54 / 74LS74A dual edge-triggered flip-flop utilizes Schottky TTL cir- cuitry to produce high speed D-type flip-flops. Each flip-flop has individual clear and. This device contains two independent positive-edge-trig- gered D flip-flops with complementary outputs. The infor- mation on the D input is accepted by the. 74LS74A datasheet, 74LS74A circuit, 74LS74A data sheet: TI – DUAL D-TYPE POSITIVE-EDGE-TRIGGERED FLIP-FLOPS WITH PRESET AND CLEAR.
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Look up the data sheets for the devices, compare pinouts, compare truth tables, etc.
I had also previously used Mouser for some stuff, but they have to have the worst search on any site I have ever seen! I learned the hard way on some cheap TTL replacements from Mouser. Many times you can get a small qty of common chips, shipped, for a buck or two.
I am always impressed datashfet the amount of knowledge that some of you all have! Again, thanks for the information, everyone! It is definitely frustrating at times, simply trying to digest all of this information. You have to be careful when mixing families due to drive capabilities.
C most often means ceramic but TI uses J; some others used D P most often means plastic but TI uses N Another bit of data sometimes coded in the suffix is the temperature range i. A good book for reference is the TTL Cookbook. It has a lot of great information. I actually did just that today, and dtaasheet some from eBay. I know that the 74 is a dual d-type flip flop, while the is a hex d-type flip flop with clear, and the is a quad d-type flip flop with clear.
Okay, I will answer the why first. Wouldn’t the board just ignore the extra inputs? You have to be careful because the suffix denotes packaging and you don’t want to get a SIP or surface found when you want DIP.
Instead of waiting two weeks too, if I were you i’d just bite the bullet and order some of those particular chips. I know from know on to just grab them from eBay with free shipping! I have been trying to learn the datasheets on these things.
In most cases, if the last numbers are not the same, then the IC is not plug-in compatible. It’s old however you can still find them on Amazon. You don’t really need to worry much about fakes for the standard TTL families, in my opinion.
Same D type Flip Flops, but without the extra features of a Also just order from U. It would be datssheet if there was datashheet a guide somewhere as to what the suffixes on some of these chips mean I prefer Digikey over Jameco as they have more parts, and the Priority Mail shipping is usually cheaper provided you don’t order anything to heavy.
I was a little worried about fakes, although like you said, on inexpensive chips, there isn’t much incentive. If it had a standardyou may not be able to replace it ddatasheet a 74LS74 depending on how many connections there are to the output.
I always use US sellers only, and found one with free shipping. The 74l74a side datasgeet Digikey is the site can be hard to navigate to find what you want, but once you get used to the parametric search it is actually pretty fast. The manufacturer sites are also good for getting specifics about what you want. Data sheets are also VERY helpful when replacing chips with one from a different family.
The suffixes are often manufacturer-specific, so you’d need to consult that manufacturer’s datasheet daasheet hope it’s detailed. I had ordered a bunch of odds and ends from Jameco, so I ordered the chips with that stuff, but man they kill you with shipping, and then it is slow to boot! Not all parts are the same.
74LS74A Datasheet(PDF) – TI store
Dstasheet middle two characters denote specific of the family. Should we ignore that they don’t have the same number of pins? Is there a reason I can’t sub one of these two for the 74? I hate to wait another week or two for one chip. Hopefully, I will be answering the questions one of these days!
Mouser is another good source as well. I am fairly new to the hobby, but am really enjoying learning.
It was frustration from knowing I have to place another order just for one chip!!! This is where datasheets are VERY helpful.
When you start getting into TTL PROMs and older 8 bit CPUs, which are usually pretty expensive and have been discontinued for a fairly long time, then you need to verify what you are getting.
Also, when you say inputs do you mean the number of flip flops or the actual inputs to the flip flop? Thanks for the reply! If it’s cheap though a quarter there’s no incentive for it to be faked and usually you should be alright. Thanks for the help, everyone.
The datasheets are useful as far as packaging goes. Definitely a learning experience. In general, it’s fairly safe to ignore the suffix, as it’s usually not of any real consequence for arcade applications. Of course, maybe there is, and I am just too dumb to find it, lol.
Lol, crap, I was thinking they had the same number of pins. Quite often, at least one of the suffixes refers to the package.