• State TI Thinks Resolved
  • Locked Locked
  • Replies 5 replies
  • Answers 2 answers
  • Subscribers 47 subscribers
  • Views 135 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

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.

DAC3283: Using IOUTA1 and IOUTB1 to drive 50 ohm load

ROSHAN LAL SHARMA
Prodigy 70 points
Part Number: DAC3283

We are planning to use IC DAC3283IRGZT in our board design.dr-ve-10-mo_datasheet.pdf

We want to connect DAC output to RF amplifier having input impedance of 50 ohm.

We have 2 RF amplifier, so we will use IOUTA1 for first RF amplifier and IOUTB1 for 2nd RF Amplifier.

Can we connect IOUTA1 output directly with 50 ohm load RF amplifier.

RF Amplifier datasheet is attached with this mail.

  • 0
    TI__Guru 67904 points

    Hi Roshan,

    No, you cannot connect IOUTA directly to a 50ohm load. The DAC3283 output is current sink based design and requires a 3.3V bias for the current arrays. Please see attached app note for recommendations:

    https://www.ti.com/lit/an/slaa399/slaa399.pdf

    -Kang

  • 0 in reply to Kang Hsia
    Prodigy 70 points

    As per application note Section 3.2 illustration fit our design requirement of 500mVpp output voltage and 50Ohm load. As per my understanding IOUT2 will be complimentary output of IOUT1 and similar design can be done for another output IOUTB with its complimentary output. so that 2 RF amplifier can be controlled with single DAC3283.

    Also suggest part code of 1:1 Transformer used in the illustration.

  • 0 in reply to ROSHAN LAL SHARMA
    TI__Guru 67904 points

    Hi,

    The balun part number depends on your frequency range, and it is applications dependent. TI cannot make recommendations at this point. You can post on this forum and we can see if it is suitable.

    -Kang

  • 0 in reply to Kang Hsia
    Prodigy 70 points

    Frequency range will be around 400MHz. Also please confirm on below point:

    As per my understanding IOUT2 will be complimentary output of IOUT1 and similar design can be done for another output IOUTB with its complimentary output. so that 2 RF amplifier can be controlled with single DAC3283.

  • 0 in reply to ROSHAN LAL SHARMA
    TI__Mastermind 19415 points

    Roshan,

    Your understanding is correct, IOUT2 is the complement (180°) of IOUT1 for each channel. An example balun for this configuration meeting 400MHz would be mini circuits ADTL1-12+, however as Kang mentions above, you should confirm this on your own. Also, please note the component value correction below to achieve a 50ohm differential impedance at the input side of the balun. The same configuration can be used for IOUTA and IOUTB output current sinks.

    Regards, Chase