Oct 18, 74LS Datasheet – Bit Random Access Memory – TI, 74LS pdf, 74LS pinout, 74LS manual, 74LS schematic, 74LS Request ETC 74LS BIT RANDOM ACCESS MEMORY(With 3-State Outputs) online from Elcodis, view and download 74LS pdf datasheet, Logic. ; Manufacturer: Major Brands; Manufacturer no.: National Semiconductor [ KB ]; Data Sheet (current) [ KB ]; Representative Datasheet, MFG.
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After a few minutes, the chip itself begins to heat up so badly that it burns at the touch. Here is what I imagine.
Welcome to our site! I’m usually pretty good at spotting such “revivals”, but this one escaped. I got mine from a ebay seller.
Email Required, but never shown. Look at the datasheet again.
So question to you – where did you source yours? Sign up or log in Sign up using Google. They were only made in the s. LED’s are diodes and will pull down the outputs to their operating voltage, around 2 volts.
It’s neither elegant, nor efficient but it does perform the function. Electro Tech is an online community with overdatasheeet who enjoy talking about and building electronic circuits, projects and gadgets. Notice also that the identical post has occurred on multiple forums. Forums New posts Search forums. The only databook I have that has anything on it dates fromand byit was no longer listed in any of them.
(PDF) 74LS189 Datasheet download
Here’s comment from Ben’s page you refer to in your question:. Note that this is a very old chip.
First, you do not want the output to drive LED’s without a current- limiting resistor. So from your answer I will try to get a few of the chips from jameco since the ones I have are probably defective.
It is never good to allow inputs on these types of devices to float, or they can draw high current and get hot or even become damaged. Note that the value given is positive 40 uAwhich means that the external circuit must source current in order to drive the input high — i.
I thought pullup resistors were only necessary for CMOS. Papabravo Well-Known Member Oct 10, Where are the pullup resistors for your switches?
TI has a pretty good discussion if you want to understand more:. I cheched Jameco but they do not ship to Finland.
integrated circuit – 74LS chip overheat – Electrical Engineering Stack Exchange
Of course you need it ASAP. I also have this same problem and have ordered from two different ebay sellers already and they are all faulty. Home Questions Tags Users Unanswered. If you search over internet using query “74LSAN heating”, there’s a video by Ben Eater exactly on the subject, with people comments expand the replies on that page to see them: Media New media New comments Search media. The chips did not work and heated up very quickly, I followed the RAM videos multiple times and consulted the datasheet to ensure I wired the chip correctly.