high noise when using DCDC in TX mode

[victor passe]

Hi, This is what constant carrier looks like at 2450MHz on my custom board using DCDC disabled

This is with DCDC enabled:

It can also look much worse with no real peak and just a wide band of energy,

I have followed the reference schematic in the product spedification. What could be the problem?

[AmbystomaLabs]

It's broadband noise because it is PWM and the duty cycle isn't constant since the load isn't constant.

The noise is largely a function of your layout but also component parasitics play a role. Not all passives are created equal even though vendors like to tell you otherwise.

Soldering can be an issue too. Wetting on a QFN can be problematic sometimes and the poorly wetted connection has its own parasitics that add to the mess. You should do a visual inspection under a microscope just to confirm well wetted connections. You might want to pull a few just to make sure your vendor properly pasted the epad.