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Several Questions about the AD75019

Question asked by lukewarm58 on Mar 1, 2017
Latest reply on Mar 9, 2017 by lukewarm58

Hi. I have a few questions regarding the AD75019. Please let me know if I have been unclear or if you require any additional information. 


Thanks in advance,



Question 1   

I would like to confirm the accuracy of the note at the end of the following link which suggests grounding pin #39 to reduce crosstalk.
   Comment: Also pin #39 on the AD75019 which is marked as a NC (no connect) on the datasheet should be connected to    an analog ground. This pin is actually connected to a shield that should reduce crosstalk.


Question 2

I will be using the AD75019 to route guitar (audio) signals through various combinations of effects pedals. My current prototype has six send/return combinations connected to the AD75019. Depending on the configuration of my system, anywhere from one to six of the send/return combinations may be active at a given time. I was wondering if it is advisable to ground unused send/return pairs in order to minimize crosstalk and improve noise immunity.


Question 3

Referring again to the link in Question 1, I have a question concerning the current draw of the analog supplies (Vdd and Vss). The following is taken from the link:

      Analog Supplies:
      +/-12V supplies, with a serial clock of 5MHz, analog supply current is 1mA.


How was 1mA determined? All I see on the spec sheet is a maximum current draw of +/-70mA. Aside from direct measurement, is there any way to estimate the current draw as the serial clock frequency is reduced? Is this value affected by the number of switches being engaged/disengaged per 256-bit data transfer?


Question 4

This is more for personal interest than anything else, but I was wondering when the AD75019 was first released. I see that the copyright on the datasheet is 1999, but I know how easily those dates can be mixed up. Just curious.