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DAC80504: DAC80504 SNR

Part Number: DAC80504
Other Parts Discussed in Thread: TLV5614, DAC80004

Hi Team

Customer want to choose DAC80504 to replace TLV5614 to improve DAC output signal’s SNR feature.  But I don’t find this spec value in DAC80504’S DS.

Can you kindly help for the below question?

  • If the output noise density can be expressed as SNR?  
  • compare DAC80004 with b0504, 80004 has lower output noise density, if it means 80004 has better SNR feature?

 

DAC80504

dac80004

  • Hi Harry, 

    I will respond here instead of your email to keep the communication in one place. 

    Yes, a smaller noise density is better, but you have to pay attention to the test conditions that the noise specs are being given at as well as the bandwidth you are using. You’d calculate the total noise by multiplying the voltage noise by the square root of the bandwidth of the circuit. Sometimes it is better to look at the typical plots.

    The DAC80504 is on the left and the DAC80004 is on the right. You will see that the DAC80504 has very similar, but slightly smaller, noise to the DAC80004 when it is using a gain of 1.

    DAC80504:

    DAC80004:

     

    SNR is equal to the (largest possible output/total noise in the given bandwidth) . The bandwidth used for this SNR spec is 20kHz as shown in the test conditions. So, you can take the SNR spec given in the TLV5614 and convert it from dB to Vrms, and then divide it by the largest possible output which is 1.774Vrms (5vpp). Then you will have the inverse of the total noise for a bandwidth of 20kHz in Vrms. This value would be comparable to the noise specs given in the DAC80504 and DAC80004 datasheets.

    Best,

    Katlynne Jones 

  • Hi Katlynne

    Thanks for your respond!