Tuning the MRFX1K80H for Class AB linear operation in 27 MHZ Circuit

[dan-in-sd]

Hello,

Im getting some conflicting data on the proper operation for Class AB linear amplifier using a circuit very similar in a many respects to the NXP 27MHz Reference circuit for the MRFX1K80H as shown on Page 6 - 10 in its datasheet

Currently I see in the datasheet that 200mA is all the DC Bias required, Iq (A+B) = 200mA,   but is that for Class C operation??    There are other forums that say for best Class AB performance from this NXP device,   you need  1 to 1.5Amp total  Bias Current       (  Iq (A+B)  =  ~ 1.5 A  )

Vdd= 57.0 Vdc

P-in =   3 W,   CW/SSB

Po = 1200W

Please help shed light .    This is for an  3 - 30 MHz Linear HF Amplifier application. Thank you

Dan K

[ErikaC]

Hello,

MRFX1K80H class AB amplifier would have flat gain curve and low IMD at ~ 2A quiescent current.

Hope this helps.

[dan-in-sd]

Agreed that IMD would be low and have flat gain curve,    but,    there doesn't seem to be a lot of performance gain from say running it at 1.5A  vs   2.0A.      In fact the device would run a bit cooler with the slightly lower quiescent current,  yes??