I'm working with an AD9162 device using only NCO Mode via the SPI interface. I'm working on implementing the TX_ENABLE pin to turn on/off the DAC output (this pin is connected to an FPGA). I have set register 0x03f to 0xc2 which I thought would turn on/off the DAC output solely based on the value provided to the TX_ENABLE pin. It appears this is somewhat working, but I noticed a strange occurance. At first, the DAC output is not there, then TX_ENABLE goes high and I see a sinusoid at the desired frequency - but the amplitude is smaller than expected. Then, when I clear and set TX_ENABLE again, the sinusoid amplitude increases. I am thinking this is related to the ability of the TX_ENABLE pin to affect the full-scale current of the DAC output. I do not believe I am setting the bits to do this however.
Can someone give me a description of how to properly control the TX_ENABLE pin based on the settings in register 0x03f? Am I setting the register correctly for my intended behavior? Any help is appreciated!