Hi Poul, I've been reviewing microchips literature and the way I read it is that the DAC isn't sensitive to staying at a fixed value. If it's on, the FIFO is fed to the DAC. If the FIFO is drained, then the user-settable default value is fed to the DAC. When the output amp is turned off, it goes to a high impedance output. I also noticed that Finput can vary from 0-45 khz. I'm not certain what a 61db SNR would mean at DC values. I see that the specifications are for a 15 uA load. I assume that's not hard to meet with a typical op-amp.
It's interesting that in one paragraph they call the DAC default register a safety feature for industrial control applications, and then a few inches later a black box warns that it's not recommended for control type applications. Bob ________________________________ From: Poul-Henning Kamp <[email protected]> To: Bob Stewart <[email protected]>; Discussion of precise time and frequency measurement <[email protected]> Sent: Monday, June 2, 2014 4:08 PM Subject: Re: [time-nuts] "Audio" DAC for GPSDO? In message <[email protected]>, Bob Stewart writ es: >Could someone explain to me how such an audio DAC differs from a non >-audio DAC and why it's not suitable for this application?=A0 Is this just >a disclaimer from microchip to avoid liability or is there some practical >reason to go with a traditional DAC? A lot of them have DC protections, so you can't leave them at a particular input value for very long before they go into safety mode and clamp the output to zero. Your speakers love them for this, your OCXO not so much. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 [email protected] | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
