GSM PA current consumption so big ?

[xinxin]

When link to the CMU200 , the current consumption of PA is so big , it reach to morn than 1A when PCL=5. Could you help me to resolve this problem for PA design or something about the RF layout?

 

[rhjang]

Hi xinxin

Does the current consumption is PA only or tranceiver included?

Maybe you can check the DC drop and APC(Vramp) value.
If you have PA's evaluation board you can check APC(Vramp) vs power.
Than compare to yours.
If DC drop too much then it need higher APC to achieve the same outpower, result in the higher current consumption.

 

[vfone]

At PCL 5 (33dBm output) the current consumption during burst shall be somewhere close to 1.5A.
The PA output match shall be optimized for output power, efficiency and harmonics. Usually is a compromise between these three parameters.

 

[xinxin]

1.5 A is only for PA working , or for total working?

 

[mckinson]

I think 1.5A ,only for burst

 

[mckinson]

Resently ,I have made some matching from PA to FEM. The impedance is more closely to 50 ohms ,but the current is lager. I think the reason is that output power, efficiency and harmonicsis a compromise .