Hi, ShineC,

Thank you very much for your fast and kind response.

We try to control AD9106 by Texas Instruments LaunchPadF28379D 4-wires SPI bus. And your response caused some additional questions, which, I hope, you will consider with the same attention.

  1. You have written that 0000 on register 0x01 means that the AD9106 internal LDOs are not powered on. It caused two questions:
  2. Disabling of LDOs are controlled by bits 7&6 of 0x01 address, which we set in 0, like to command in the same address in the table 19 (the example 6 in DATA Sheets). We have checked the voltage at the pin 22 bypass capacitor, it is 1.8V; does it mean that LDOs are enabled?
  3. Bits 11..9 of 0x01 address are Read-only bits; when we read the register 0x01 state, we always see response 0E00, corresponding to that one in the table 19 (the example 6 in DATA Sheets), so the state of our register corresponds to required; does your note mean that for correct work of AD9106 all program bits, corresponding to Read-only registers bits, are to be set in 1?
  4. You have written that we have to take into account instructions in the page 25, but there we see the instructions, related to the pattern generator signals, and we try to use DDS generators, having its own sinus table and controlled by Tuning Word. So, we have other three questions;
  5. Is it enough for normal work of DDS to write out Tuning Word in the addresses 0x3E and 0x3F, or it is necessary to bring it to pattern or to SRAM?
  6. Is it enough for normal work to write out DDS4..DDS1 Phase offsets in the addresses 0x40..0x43, or it is necessary to bring it to pattern or to SRAM?
  7. To activate DDS what command do we need to use for to apply to pattern or to SRAM, if necessary?
  8. Due to mistake in our PCB production AD9106 pad is not connected with GND; may it prevent correct programming (any noticeable heating has not been observed)?
  9. As we see, the command “TRIGGER” opens outputs of already working AD9106. Does AD9106 foresee any command “START” for to be get in the “working” DDSes and DACs outputs state after all addresses have been loaded, or it is provided automatically?
  10. If automatic start is foreseen, what program loading algorithm have we to use?




  • Hi Vilen,

    I moved your thread to the High-Speed DACs community. Someone here will be able to help you.

    Best regards,


  • Hi Vilen,

    1. Yes, setting ‘0’ on bits 6 & 7 means that you’re not disabling the LDOs, so a 1.8V on the bypass capacitor is expected. A ‘1’ on those bits will shutdown the LDOs.


    1. For default operation of the evalboard, meaning the internal LDOs are used, bits 9 to 11 should be ‘1’. You can also choose not to use the internal LDOs, provided that you’re supplying the CLKVDD and DVDD with 1.8V. See details below.

           Using the AD9106 with 1.8V power supply

            By default, the AD9106-EBZ evaluation board uses 3.3V digital and clock power supplies. On-chip CLDO, DLDO1and DLDO2 supplies are          used. P15, P13, andP11 are not installed. It is possible to operate the AD9106 with 1.8V power supply only. To achieve this, a few changes          are needed:

    1. Set the voltage of the DVDD and CVDD regulators on theAD9106 evaluation board to 1.8V on the BOARD CONFIG tab of theAD9106 evaluation software. This will assure that SPI communication and the AD9106 clock power supply pins are powered with 1.8V
    2. Install jumpers inP15, P13 and P11. These jumpers connect 1.8V regulators on the evaluation board with DLDO1, DLDO2 and CLKLDO pins of the AD9106.


            5 & 6. Correct, the DDS has its dedicated sine look-up table that is controlled by the tuning word. Therefore, it’s independent of the pattern              at the SRAM. The DDS can be only controlled by registers 0x3E up to 0x43.


    1. No need to input command at SRAM for DDS to work. PRESTORE_SELx and WAVE_SELx at registers 0x26 and 0x27 should be selected to DDSx output and Prestored Waveform respectively. (Tables 44 and 45)


    1. We can’t say for sure, it may work but sometimes it won’t. We haven’t tested it yet. It is recommended to solder the exposed pad to DGND for optimal performance.


    1. You need to load first the register contents that you want before sending a TRIGGERB command at the GUI. New changes at the register will not take into effect unless TRIGGERB is set.