Is isolator needed or not after PA out in CDMA2000 design?

It all depends upon the application. In places with many transmitters of high power it is required. otherwise the signals from each transmitter get into the output of all the other transmitters and create IMD. On rural locations and mobile units they are not necessary unless the customer specifies them.

I agree fully. And if you use a reactive power divider to divide PA's output signal between few antenna's you must have isolators, too.
Good luck.

In these days everybody is trying to avoid isolators in CDMA-IS95, CDMA2000 or WCDMA. Now the technology allows to design PA’s which pass the ACPR spec under bad VSWR.
Before to eliminate the isolator from your design, you have to measure the ACPR of your PA under bad VSWR (usually 4:1).
Post PA loss in a CDMA phone (3 to 4 dB) it helps to isolate the output of the PA from antenna.

regards

Also if you use a reactive power sampler to detect Pmax output, you will need an isolator. If you use a directional coupler sampler, you won't need the isolator.

who can give me some documents about this point. I'm so confuse of it.

thanks very much.