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DAC121S101 Input pin robustness

nico2
Intellectual 290 points
Other Parts Discussed in Thread: DAC121S101

Hello,

I am using a DAC121S101 on my design. The DAC is driven by a FPGA which is supply by a digital power supply.  The DAC121S101 is supplied on my design by an analog power supply.


I would like to know if the DAC121S101 can withstand this failure case :

the power supply of the DAC is not present and the FPGA send data to the input pin of the DAC.


The DAC will be worsened ?

Kind Regards

Nicolas Divel

  • 0
    TI__Genius 16890 points
    Hi Nicolas,

    If the FPGA is transmitting and the power to the DAC is not on, you could damage the DAC. There are ESD diodes on the inputs of the DAC that will turn on and start conducting current in this situation. There are a couple of things that you can do. You can put a series resistor between the FPGA and the DAC so that the current into each DAC input pin is less than 1mA. An even better solution is to put a Schottky diode between each input pin and analog supply. The schottky diode will turn on at about 0.3V. What this does is that the schottky will turn on before the internal ESD diode, protecting the DAC.

    Mike