ADAR1000 interface with ADTR1107

We need some more information before we can diagnose what is the problem.

• Is this being measured on ADI evaluation boards or a board of your design?
• If on ADI evaluation boards, what gain does the ADAR1000 Rx channels have?
• What gain does the ADTR1107 LNAs have? Do all four LNAs have the same low 7 dB gain?
• How are you measuring gain?  With a VNA?

Its being measured in our custom board.

ADAR1000 in our custom board is also being set for maximum gain settings. 

As per datasheet ADTR1107 LNAs have 18dB (typ) gain. We observed gain of 0dB for some LNAs or in one ADTR1107 we saw 7dB gain.

We are measuring with Spectrum Analyser, for RF input of -20dBm.

Alongwith this some more observations;

• TX gain is proper as we are getting close to 20dB in all four channels
• control switch is toggling properly as observed from changing RF output and correct switch voltage from ADAR1000
• Gate voltages of both PA and LNA are proper
• we are following recommended bias sequencing as mentioned in ADTR1107 datasheet except 3.3V as its all supplied from common source (similar to StingRay Schematic)

Its being measured in our custom board.

ADAR1000 in our custom board is also being set for maximum gain settings. 

As per datasheet ADTR1107 LNAs have 18dB (typ) gain. We observed gain of 0dB for some LNAs or in one ADTR1107 we saw 7dB gain.

We are measuring with Spectrum Analyser, for RF input of -20dBm.

Alongwith this some more observations;

• TX gain is proper as we are getting close to 20dB in all four channels
• control switch is toggling properly as observed from changing RF output and correct switch voltage from ADAR1000
• Gate voltages of both PA and LNA are proper
• we are following recommended bias sequencing as mentioned in ADTR1107 datasheet except 3.3V as its all supplied from common source (similar to StingRay Schematic)