Hi!
I have a problem with the output power of the DAC34H84EVM. Channel A/B has approx. -11dBm output power which is as expected for an 8MHz bandwidth discrete multitone signal.
Unfortunately, channel C/D has 10dB less output power than channel A/B. Spectrum, dynamic range and so on is still very good. I have done a lot of tests but can not fix the problem.
I cannot remember if channel C/D has had 10dB less than channel A/B since the beginning (when i got it) or since the last days were I use both channels. I have extended my design in the last days to support both channels of the DAC34H84EVM.
Can I somehow fix this problem in the GUI or on the EVM?
Is it possible that I have “killed” channel C/D? If so, how could this happen and what have I damaged? I expect that if the DACs or the mixers are damaged the spectrum would look much worse and not only has 10 dB less output power.
Maybe the input matching of the LO on channel C/D is damaged but I have never exceeded the specifications (LO input power and so on…) of the devices. I've dealt with both channels equally. I want to prevent that this will happen again.
Thx for support!
Martin
Update:
I have done a frequency sweep on both channels (5dBm LO from 1.5-2.5Ghz). See the picture for details. The blue one is channel A/B (the good one) and the yellow chart is channel C/D (the bad one). I have also measured the output of the ADC but they are ok. So I think the C/D channel quadrature modulator is faulty/defekt.
I have also seen that I have a Rev A. EVM. Under microscope i have seen that this Rev. is having the Analog Devices ADL5372 Quadrature Modulator with 1.5-2.5Ghz freq range. This is not the same as the manual describes??? I have expected the TI TRF370315 as stated in the product description... Do newer revisions also have this modlator?
