The maximum junction temperature of the IRS20124S is 150°C, but it's recommended to keep it below 125°C for reliable operation.
Power dissipation can be calculated using the formula: Pd = (Vcc x Icc) + (Rds(on) x Iout^2). You can find the values for Vcc, Icc, Rds(on), and Iout in the datasheet.
A good PCB layout for the IRS20124S should have a solid ground plane, short and wide traces for the high-current paths, and a decoupling capacitor (e.g., 100nF) close to the device. Avoid vias and sharp corners in the high-current paths.
Yes, the IRS20124S is suitable for high-frequency switching applications up to 1 MHz. However, you should ensure that the device is properly bypassed and decoupled, and that the PCB layout is optimized for high-frequency operation.
You can protect the IRS20124S from overvoltage using a voltage clamp or a zener diode. For overcurrent protection, you can use a current sense resistor and a comparator or a dedicated overcurrent protection IC.