ESD protection for high swing application (PA for example)

at the end of the RF transmitter signal chain, drive amplifier amplifiers the RF signal to high voltage swing. Theoretically, the swing can be as high as 2VDD. For example, if the drive amplifier is connected to 2.5V supply through a RF choke, then the output swing can be as high as 5V.

I was just wondering how one would make the ESD pad for such large swing. Usually we have power rails connected to a diode in the signal pads. Therefore, assuming 0.7V turn on voltage for the diode, the signal swing can be either as low as -0.7V or as high as 3.2V. How do you handle higher voltage than that? How do you reach 5V?

any document or explanation will be helpful


Thanks you.

Few series connected diodes will help you..
For 5V, you can connect 8 diodes in series..

ESD protection?, is not your PA device is connected to the Vcc line by a low impedance RF choke?
Frank

sorry,, this is mostly coming from my lack of knowledge in ESD.
If the drain is indeed connected to a low impedance VDD through the RF choke, then is the ESD protection not needed? Then wouldn't all power rail(VDD,VSS) pads not need ESD since in the end they are connected to some other low impedance voltage?

Let me know THanks.

ESD protection is needed when the part is handled or while it's transporting.In additional to, because of slow transient response of L-C component at Vdd, the part can be damaged when a fast transient voltage is applied to the drain..