AD9765 influence of the clocks

Question > 1. Is it possible to clock the both DACs with different clocks like 33MHz and 66MHz? What influence does this have on the specs, especially for the matching of the two channels when master/gain control mode with one resistor is used? > 2. In the datasheet the schematic of the Eval-board is given. But the values of the inductances (L1, L2) are missing. What do you recommend? Answer Q1. When the part is used in dual port mode, the AD9765 acts as two completely independent DACs. You can run the two DACs at different clock frequencies. I am waiting on feedback from the HSC group on how this will impact performance. I would expect that there will be some cross talk between the two DACs but you should still be able to achieve comparable dual and four Tone SFDR numbers comparable to those given in the datasheet for both DACs. I would expect that the majority of cross talk between channels measured in a system could be attributed to PCB layout and design. Operating the part in master/slave gain control mode should not have any effect on the performance of the part. This resistor is only used to set up current mirror circuits. Q2. L1 and L2 are not inductors as such, they are ferrite beads used to filter the power supply. Their exact value is not critical and will in fact depend on the frequency content of your power supply. A few 10s of micro Henrys will suffice. ------------------------ Some additional comments " There should be no problem at all running the two DACs at different speeds. With the exception of the internal reference, all functions of the DACs (CLK, reference amplifier) are independent of each other in dual DAC mode. Concerning L1 and L2, the higher the inductance, the better. Along with the bypass capacitors nearby, they form a lowpass filter for the power line. The lower the cut-off frequency of this filter, the better. "

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AD9765 Production
The AD9763/AD9765/AD9767 are dual-port, high speed, 2-channel, 10-/12-/14-bit CMOS DACs. Each part integrates two high quality TxDAC+Â® cores, a voltage...
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