In the ADV7390_7391_7392_7393.pdf Revision E datasheet I read that the ADV7393 DAC resolution is 10-bit. On page 6 figure 3 however, three 12-bit DACs are indicated. So, what about that?

In the ADV7390_7391_7392_7393.pdf Revision E datasheet I read that the ADV7393 DAC resolution is 10-bit. On page 6 figure 3 however, three 12-bit DACs are indicated. So, what about that?

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Hi, AxonEZ.

Good day! As additional information on the DAC's specification of ADV7393, the 12-bit is the resolution while the 10-bit is the accuracy. These two parameters of converters, resolution and accuracy, are commonly interchanged and sometimes misinterpreted. For you to visualize what the datasheet specifies, the

**resolution is the number of bits in its digital word**while the**accuracy is the number of those bits that meet the specifications**. These two are usually affected by SNR. So to get these number of bits based on the datasheet, let's look at the SNR values on page 11 of the datasheet under Video performance specifications.For Accuracy:

let x = number of codes

let n = number of bits

58 dB = 20 log x --> use 20 log because it's voltage

x = 794.3282347

n = log2 x --> log2 = log sub 2

n = log2 (794.3282347)

n = 9.6336 bits ~ 10 bits

For Resolution:

let x = number of codes

let n = number of bits

75 dB = 20 log x --> use 20 log because it's voltage

x = 5623.413252

n = log2 x --> log2 = log sub 2

n = log2 (5623.413252)

n = 12.4572 bits ~ 12 bits

Therefore, for this 12-bit DAC the only bits that meets the specifications of ADV7393 is 10-bit. This is not to say that the 2-bits are irrelevant.

For a shorter computation, use SNR in dB = (6.02 x n) + 1.761.

Hope I helped you understand this DAC specification. If you still have queries, just let us know.

Regards,

Anna

Interesting question, seems to be a discrepancy in the datasheet, checking in to it.