dimensionsdrawingintegrated-circuitpackages
I looked at the dimensions drawing of the SOIC‑14 package from texas instruments.
But I am a bit confused about the way texas instruments marked some lengths.
Why there are two values seperated by a horizontal line for one length?
Which one is the correct?
Just to be clear what you're asking about:
The two rows in the dimension table are giving the min and max for each dimension. Theta can be between 0 and 7 degrees. D can be between 1.85 and 2.25 mm. Etc.
There is not necessarily any correlation between one dimension being near its min or max value and another dimension also being near min or max. For example, theta and D are probably not correlated.
On the other hand, others of the dimensions are likely to be correlated. For example, if theta is near 0 degrees, A1 might also be near its minimum value.
You have it right.
This is the "raw" or "peak" transfer rate that you get within a single burst of data. The actual long-term throughput will be somewhat less because of the overhead associated with starting and stopping bursts. However, if the memory controller is smart about interleaving operations on different "banks" within the memory chip, it is possible to get sustained throughput that's very close to the peak value.
With multi-chip memory modules, you simply multiply the numbers for a single chip by the number of chips, since they simply operate in parallel.
Best Answer
These are minimum and maximum size (in both inches and mm). As you see the difference is very small. Simply make sure that everything still works as intended with both sizes; regarding footprints that means making the pads slightly larger than the maximum size. In case you solder by hand make them about 1mm longer than the leads too.