• State Resolved
  • Locked Locked
  • Replies 1 reply
  • Subscribers 47 subscribers
  • Views 455 views
  • Users 0 members are here
Support feedback
Options
Options
Related

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

DAC8580 problem, filter never active

trioflex
Prodigy 30 points

Other Parts Discussed in Thread: DAC8581, DAC8580

Hi

we are currently deisgning a measurement system where we want(wanted?) to use DAC8580, mainly because it has internal digital upsampling filter and is specially designed for waveform generation. We did buy DAC8581 evaluation board (as DAC8580 board was not available), replaced the DAC8581 with DAC8580. FPGA is used to generate sinus signal and controls the DAC8580. What we can not see at all on DSO with 6GHz bandwidth is the digital filter - no matter the setting of the OSR, RST, BPB pins, DAC8580 operates in normal mode. What can be wrong? Is there some hidden trick or errata?

Antti

 

 

  • 0
    TI__Mastermind 46290 points

    Antti,

    The device should be powered up with all digital inputs tied to logic low. Once the analog and digital power supplies have settled the digital inputs may be manipulated. At this point MUTEB should be taken high for any normal operation of the DAC. For operation with the digital filter the OSR1 and OSR2 pins should be configured as desired, then BPB and RSTB can be taken high to start the digital filter. If the OSR1 and OSR2 settings are changed while the filter is active the filter will become unstable but can be recovered by toggling the RSTB pin. 

    On the evaluation module keep in mind that by default there are jumpers to ground and pull up resistors on the pins to control the digital filter from the factory. If you want to control these from your microcontroller you'll probably need to remove the jumpers and potentially the pull up resistors.