Post Go back to editing

LTC5599 how to optimize the LO leakage and the modulator side-band suppression and the sequence ?

Hi all,

Our custmor try to optimize the LO leakage and the modulator side-band suppression, while referring to AN-1039.

https://www.analog.com/media/en/technical-documentation/application-notes/AN-1039.pdf

The following functions are implemented in the LTC5599.
• Coarse digital gain control with 1dB steps
• Fine digital gain control with 0.1dB steps
• Gain-temperature correction
• DC offset adjustment in the I-channel
• DC offset adjustment in the Q-channel
• I/Q gain balance control
• Disable Q-channel
• Continuous variable gain control

At first, for starting to optimize the LO leakage,  

how to optimize the LO leakage and the sequence ?

Is there any restriction on the order of adjusting each function?

The actual measurement data was as follows.

After tune the digital gain control and DC offset adjustment, again adjust the gain again.

Is this data the normal behavior of the IC?

Please advice to us about the Internal Gain Trim DACs and sequence to optimize.

Best regards,

sss