Valentin,

I have very good experiences with the Zarlink MH88437 you already mentioned (and I don't think the pin count should be any problem). Zarlink also has an Application Note which contains a lot of useful information.

The choice you make should be made first and foremost on the technical and legal requirements, as Andy Neil already told you in a previous post. Then you can start looking at things like size, power consumption and price.

As an alternative for the -5V supply for the op-amp in that Cemerec application note you can use a rail-to-rail output opamp with a single +5V supply and connect the '+' input to 2.5V, which you can easily make using two resistors. You should also add a capacitor to GND for noise filtering.

Best regards,
Rob.