Other Parts Discussed in Thread: LMK04826,
Tool/software:
Dears,
My customer is using DAC3484 in a RF station project, and find the measured IMD3 may be <60dbc at some frequency range, the performance is not qualified as the datasheet shows. The customer use LMK04826&TRF3705IRGET as clock generator and modulators. Their configuration is: fDAC=1228.8MHz, 8x interpolation, fDATA=153.6MSPS, IoutFS=20mA, fout=184.32MHz. the below figure shows the intermodulation test value at the band boundary point (IF signal directly output by DAC)
The datasheet lists the normal range of IMD3 should between 58 and 65dbc. as shown in the above figure, the test result on the customer PCBAs shows that at band boundary point, IMD3 is 58 to 61dBc, although at the center of the band 184.32MHz, IMD3 is around 63 to 65dbc, the customer's standard is IMD3 to be >60dbc, so some PCBAs could not pass the test.
the customer used DAC3484 previously, it worked ok, the issue happened when the new project is required to support expanded frequency scope, and the corresponding DAC output frequency was also expanded accordingly.
The customer tested the PCBA with signal source directly supplies the signal to the DAC3484, and the DAC directly outputs the signal differential line to connect the balun for direct measurement.
would you please help to have a look of the issue? if any further information, data you may need, please let us know.
In addition, the customer also wonder if DAC3484 have a register to support the debugging function of directly sending dual-tone signals?
thanks a lot!
