flatulent
Joined: 19 Jul 2002
Posts: 4866
Helped: 292
Location: Middle Earth
|
 06 Feb 2005 6:47 Re: What is meant by 54 and 74 prefix? |
|
|
|
Also, these were the original TTL logic family prefix. These two digits were followed by letters for improvements and in the early days there was a final letter on the part number indicating the package. My favorite was the 74L00N, loon being short for loonie. This was the not schottky low power family in a DIP package. The development of this logic family, the first successful one, was totally funded by the US military.
As processing technology became better, there was no difference in performance between production lots and this dual temperature range labeling was abandoned. One of my friends in the early days of National Semiconductor told me a story that all of the parts would meet the highest of the three National temperature ranges. National would label the same part at the model number of what the customer wanted to buy and charge them a premium price if it was a higher temperature range version they wanted.
|
|
