datasheeth-bridgespecifications
Studying an IC component's datasheet, somewhere you meet electrical characteristics for the device. Device is tested under specific conditions (e.g. Vs).
How electrical characteristics are affected when conditions are different? How can I specify the new values?
In the case of H-bridge L6205N (PowerDIP20), what about values of V-IL, V-IH, I-IL, I-IH, when Vs isn't 48 V but 9V?
This difference could be explained in a number of ways, though none definitive without knowing more about the device than the datasheet (necessarily) reveals. These may include differences between the actual structures of the underlying devices within the packaging (most likely), as well as differences in the estimations, testing practices, and / or acceptable margins of the companies or even specific engineers involved in their design and documentation. It is conceivable that typos in the actual datasheets themselves could be blamed. Nothing is certain until it can be proven that it works, and even then, things (manufacturing processes, etc) can change over time without you (or even the distributor, documentarian) necessarily being informed. Good testing procedures, performed on all devices prior to distribution (i.e. quality control) and wide operational margins for parts selection can help to insulate you from problems inherent in both mis-specification and changes in manufacturing over time, but don't be surprised if your (initial) design requires re-work somewhere along the line because of these things.
It's saying that the transistor can be operated up to 45V. This has to be specified as a minimum value because if it was specified as a maximum value then you wouldn't know the lower limit that might cause it to fail.
It's a guarantee on performance - if you bought a car that was guaranteed to do 150mph you'd want the MINIMUM guarantee to be 150mph. It can't be expressed any other way.
On the other hand if the car manufacturer specified acceleration from 0 to 60mph as 4 seconds, you'd want that to be a maximum value i.e. you can always guarantee to do 0 to 60 in 4 seconds (max). Think about it.
Regarding hFE, use a better transistor that has a full spec. The spec you linked doesn't even have a part number other than the generic (but suspicious) name "T0-92". Here's what the current gain for the BC847A transistor looks like in its data sheet: -
This is the sort of data I'd expect to see in a data sheet.
Best Answer
In this case of L6205N, turn to section "Logic Inputs" on p.8. The input circuits (Schmitt triggers) are always powered by +5V. The H-bridge chip has an internal regulator for the digital circuitry. So, it turns that V-IL and V-IH are pretty much independent of the H-bridge supply voltage Vs.
Often and in general, when some parameter is tangibly dependent on some other parameter, the datasheet has a chart or a formula for the dependence. At the same time, the tables might show the parameters for some common conditions (supply voltage, temperature).
If you're reading a datasheet and suddenly think that some info is missing at the moment of reading, keep reading. Possibly the information is further in the datasheet. Only after you've read the whole thing and reflected upon it, you can wonder if something may be missing in the datasheet.
Often manufacturers omit some relationships, which are obvious, weak, or unimportant. If they write them all out, the datasheet will be really bloated. It's obvious for the manufacturer what's obvious and what isn't, but that may be less obvious for you. Over time, you'll learn to recognize, which variations and impacts thereof may be important, and which ones are not.