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DAC43204: Schematic Review

Tilden Chen
Genius 9551 points

Part Number: DAC43204
Other Parts Discussed in Thread: OPA2994

Hello DAC Team,

I'm an applications engineer from DLP team developing an EVM featuring your device, DAC43204. Please let me know if you have any suggestions to improve the schematic.

Schematic - p67 PLM EVM - DLP135.pdf 

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  • 0
    TI__Guru 57363 points

    This looks okay to me - what is the purpose of the OPA2994? do you need the high-current drive?

  • 0 in reply to Paul_Frost
    TI__Genius 9551 points

    Hello Paul,

    Thanks for your reply.

    I added the unity gain amplifiers (OPAx) for stability. In one test case we want to evaluate having the DAC output a signal changing at 20 kHz and I wasn't sure the DAC output buffer would be stable with a 10 nF load. I was initially emailing your marketing team and received a Cadence simulation of the DAC output buffer, the crossover frequency (with 200 pF load) seemed pretty close, around 200-300 kHz. Seemed safer for the design to just buffer the output and minimize further reducing the bandwidth.

    Per the d/s the output impedance, Zo, also seemed high, I was worried about possible divider/loading.

  • 0 in reply to Tilden Chen
    TI__Genius 9551 points

    Please also let me know the device operating quiescent current frequency so I can further optimize Cin. Thanks!

  • +1 in reply to Tilden Chen
    TI__Guru 57363 points

    There is an internal oscillator with a frequency of 25MHz, with much of the internal digital operating at 12.5MHz.  CIN can be calculated to improve noise at these frequencies.

    Thanks

    Paul