It's time for an overview of the ISO-7637 standards and some related specifications. ISO-7637, this is a spec for road vehicles, and it defines electrical disturbances from conduction and coupling. It defines how you will test it, what some of the specs are, some of the test circuits.

A lot of that's in Part 1. In Part 2, we have the electrical transient conduction along supply lines only. This is where the actual waveforms that we all discuss are defined.

ISO-16750-2, this is environmental conditions. And it contains a couple of specs which used to be in 7637, but they have been moved over to 16750-2. And this is reversed battery hook up and load dump.

We've got ISO-21848. This is nearly identical to 16750-2, environmental conditions, but it is specs for 42-volt vehicles as opposed to the more common 12- and 24-volt vehicles.

We'll talk briefly about some other regional standards bodies that exist all over the world and OEM specs. Every manufacturer has their own version of 7637. And then we'll look at all the test pulses, which are the signals that are actually applied to our circuits. And these are used to test the circuits to ensure that they will survive in an automotive environment.

So ISO-7637, we've basically got three parts in existence today and two more in development. The three today are Part 1, 2, and 3, definitions and general considerations. This tells you what we test, how we test it, why we test it. Part 2 is the actual test waveforms and detailed specs for power lines, supply lines. And test 3 is a set of requirements for transients, but this is on lines other than supply lines-- basically, for control and data lines.

There are also a couple of specs in development. One of them is for transients on shielded that high voltage supply lines. And then Part 5 is going to be a definition, or guidance, on how to set up test generators to run the voltage droop, cold crank tests, so that we can get the same answers all over the world no matter who runs the test. Out of all these, for the purposes of this presentation, what we're really just interested in are Part 1 and Part 2.

Next, ISO-16750-2, and this is environmental conditions and testing for electrical and electronic equipment. So this deals more with, I'll say, external sources of transients or electrical anomalies as opposed to the internally generated anomalies that are created in 7637. Again, five different parts. There is the general, electrical loads, mechanical loads, climactic loads, and chemical loads. But for the purposes of this discussion, we're going to be focused on the electrical loads.

Then there's ISO-21848, very similar to 16750, but this is for 42-volt vehicles instead of 12- or 24-volt vehicles. In the table of contents we see here for 21848 is nearly identical to that which we see for 16750.

Other regional standards bodies-- there's JASO in Japan. There's EU in the European-- the European Union has many different standards. In North America, SAE has a lot of standards for cars. And this just is a small snapshot of some of the requirements that are out there for transient standards in vehicles.

As you might imagine, there is a lot of similarity between the requirements in many of these standards. And in some cases, there is an almost one-to-one correlation. As an example, this table shows a cross-reference between ISO standards and SAE standards. And for the transients that we are concerned about for this presentation, really it's ISO-7637-2, whose closest equivalent-- and it's pretty close-- would be SAE J1113/11.

Another source of many standards are the OEMs. These are the car makers, and all of them have their own internal standards that they control, which describe how their systems will meet compliance with ISO-7637. There are a few examples right here that TI has worked with pretty extensively from various car makers. And they are all designed to comply with one overall standard, like ISO-7637 or SAE J1113.

Many of these OEM specs differ in how they distribute the protection responsibilities. Is there centralized protection, which eases the burden on all the downstream systems? Or does each downstream system have to be able to take a full 7637 transient load on its own? Some ESAs, or Electronic Subassemblies, only have to survive 20 volts, whereas others must survive up to 150 or more.

And it's important to remember that precise requirements are more important than the top level spec driving them, when you're working with your customer. If they just say, I need to be 7637 compliant, it's important to ask, what does that mean for you in this subsystem? This is particularly important for Tier 2 suppliers that could be building a subsystem that might go into many OEM vehicles.

And when I say that there are many OEM standards-- and I was just showing you a small sample-- I was speaking the truth, because this isn't even a full collection of all the OEM standards out there. The message is, understand in particular what your customers' requirements are.