The second device is a logic level device. You can also tell these types of devices by the gate-source threshold voltage Vgs(th). In logic level devices it is generally 2.5 volts or less.
Unfortunately, many of the companies have devised their own " brand - names " for logic-level devices. Everything from TrenchMOS ( philips ) to OmniFET ( st-micro ), etc. Many of the logic level drive devices contain added circuitry and features such as current limiting, sensing, over-heating protection and gate feedback signals, so the companies come up with names for the technology.
In the case of International Rectifier, they used to be all in the IRLxxx line for logic drive devices. For example, they did a IRL540, a logic drive version of the regular IRF540.
Easiest thing to do is use the parametric search on a manufacturers website to select a device with the basic properties you want for RdsON, Id, package, etc, and then see if the search returns any devices that are logic level drive.
International Rectifier or any of the other companies, don't do a particularily good job of separating its logic level devices on their website. You have to know what families contain these devices... and if you knew that, welll.....