Electronics Datasheets is a search engine containing over 9 million parts from thousands of manufacturers along with a comprehensive resource of datasheets.In some cases, newer releases of data sheets contain less information than their counterparts from yesteryear. VI(on) Test Circuit Figure 8. II(on) Test Circuit Figure 7. II(off) Test Circuit Figure 6. ICEX Test Circuit Figure 5. II IC h FE IC II V R Open IR Open V CE IC V I Open II Open Open V CE IC II(off) Open V CE ICEX Open ULN2803A SLRS049G FEBRUARY 1997REVISED JANUARY 2015 8 Parameter Measurement Information Figure 4.
![]() Ic Data Sheets Series And 74LS00The first logic gates I worked with were of the 7400-series and 74LS00-series families (in conversation, people would say, “seventy-four-hundred series,” when talking about 7400-series parts). All you need to do is search for them on the.When I started out in engineering, most logic circuits were TTL (transistor-transistor logic). This is made easier by data sheets, which are available for integrated circuits and are very easy to find.Notice how they cleverly used the same illustration for multiple parts in two different families. My old TTL Data book has nice (if a bit small) illustrations of the gate structure.Below is a scan of the illustration for the NAND gates. In particular, they are made with NPN transistors. Front cover of Texas Instrument’s TTL Data Book (Source: Elizabeth Simon)Instead of being made from MOSFETs like CMOS devices, TTL circuits are formed using bipolar junction transistors (BJTs). I still own a copy of the second edition. You can still obtain 7400, 74LS, and 74S parts, however, so let’s take a look at the data sheet for the TI SN7400, which also includes the 74LS00 and 74S00 parts (as usual, I suggest you open this data sheet on your screen or print it out to make it easier for you to follow along).On the first page we can see that this data sheet actually covers six different parts, so we’re going to need to pay attention to the similarities and differences between these devices. As far as I can tell, the 74H- and 74L-series parts are no longer available. Also, as we will see later, the logic levels are not symmetrical with respect to the supply voltage.In addition to the 7400-series and 74LS00-series parts, my old TTL data book also includes 74H00-, 74L00-, and 74S00-series components. Because of the asymmetrical input structure, the current required for a logic low is noticeably greater than the current required for a logic high. These drawings are followed by a Pin Functions table, which also makes it clear which pins are inputs and outputs.In the Absolute Maximum Ratings on , we are given a Maximum Supply Voltage (V CC) of 7V, while the Maximum Input Voltage is limited to 5.5V, except for the ‘LS00 variants, for which it is 7V (this is interesting I don’t remember seeing this before).Moving on to the Recommended Operating Conditions, we see differences between the parts on most of the lines. We also see that these parts are available in several different packages, including lead through-hole (LTH) and surface-mount technology (SMT).Following the Table of Contents on , package outline drawings on show the pin designations for the different packages. This is the primary difference between the 74xx and 54xx families, although there are other differences as we will see.The description section tells us that these parts have four independent 2-input NAND gates. Casio fx 115es plus fraction to decimalRemembering that these parts contain BJTs, we may want to pay attention if we intend to operate them close to the upper end of the recommended range. Remember that this is the Recommended Range and not the Absolute Maximum, so while the part may not operate exactly as expected, it’s not likely that it will be destroyed if operated slightly outside the Recommended Range.Speaking of thermal information, we also are given a variety of thermal resistances for the different package types. Most newer parts have wider temperature ranges than this. Incidentally, the 0 to 70☌ temperature range of the 74xx is typical of the commercial temperature ratings when these parts were originally developed. The 54xx also has a much wider temperature range. It’s interesting that, for all the parts in this data sheet, I CCL is much greater than I CCH (this is yet one more thing that I didn’t remember about these parts before looking at this data sheet).Unfortunately, the application report, as good as it is, does not seem to have a definition for I OS. On the other hand, since this guide, is available, I’m going to skip over some of the details.To save you the trouble of searching this 60-page guide, I’ll just note here that I CCH, and I CCL are the supply current when all outputs are high or low respectively. It covers almost all the abbreviations included in this data sheet, along with many others that we are likely to encounter.While it’s very good of TI to provide this guide, a bit of additional text in the parameter column would have saved some searching on my part. What are V IK, I OS, I CCH, and I CCL, for example?Fortunately, I was able to find TI Application Report SZZA036C — Understanding and Interpreting Standard-Logic Data Sheets — which contains more information about these data sheets than I could cover in several columns. I’ve looked at enough logic data sheets to be able to decipher most of them, but there are a few parameters with which I’m not familiar. These schematics are the same as the ones in my old data book, but they are missing from the 7400 data sheet. With maximum values ranging from 55 to 100mA, I can see why this warning is included.Before returning to the 7400 data sheet, one other nice thing I noticed in the 7404 data sheet is the schematics on. This tells me that I OS is the Output Short Circuit Current. At the end of each of the Electrical Characteristics tables, the note for I OS tells us that not more than one output should be shorted at a time also, that the duration of such a shorting should not exceed one second. In particular, why would we choose one part over another? Well, the largest area of difference is in the Propagation Delays shown in the Switching Characteristics section.First, we see that we are given two numbers (t PLH and t PHL) and that they are different for a given part. I find this arrangement convenient when comparing parameters between the families.Returning to the 7400 data sheet, let’s move on to actually looking at the characteristics of these parts. Does this make anyone else wonder if we’re really making progress? Scan of page from TI TTL Data Book (Source: Elizabeth Simon)Observe on the old data sheet how the part families are arranged across the top of the table so you can easily tell the differences between the families. The parameter tables also have a brief parameter description and not just the abbreviation. In addition to the schematics for the gates, the TTL Data Book has gate-level schematics for more complicated ICs. Quick comparison table (Source: Elizabeth Simon)A brief look at this table reveals that one of the things that is not equal is the supply current. Here is a simple table I created in an Excel spreadsheet. In cases like this, it’s often beneficial to compare the parts side-by-side with the parameters we care about in a table. The problem is that all else is NOT equal. Since faster is better, we should choose a 74S00 over a 7400, right?Maybe, if all else was equal. If you need the speed, then the ‘S00 is better, but if you want lower power, then the ‘LS00 is better. So, which one is better? Well, this depends on what you think is important. From this comparison, we can see that the ‘LS00 part has much lower supply current and input current than the other two, while the ‘S00 is much faster and has a bit more output current.
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