ADN4662/ADN4664 High-Z O/P's on Powerdown

iCarletto on May 24, 2022

Category: Software

Product Number: ADN4662, ADN4664, ADN4668

While the ADN4668 (4-ch) features dedicated Enable pins, neither the ADN4662 (1-ch) nor the ADN4664 (2-ch) has any.

Nevertheless, both their datasheets report "High impedance outputs on power-down" as a feature in the first page, but no further mention of this feature throughout the document.

How does the output high impedance should be achieved? By physically switching off the device (Vcc = 0) ?

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+1 ConalW

on May 26, 2022 8:26 AM
Yes, this is just to highlight that any powered-off ADN4662/ADN4664 will not affect the LVDS bus as the pins will be High-Z.

Regards,

Conal
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0 iCarletto on May 26, 2022 9:28 AM in reply to ConalW

Well, as the HiZ condition is referred to the output of the LVDS receiver, I guess you actually meant that when powered-off it will not affect the TTL/CMOS bus rather than LVDS.

Eventually, I plan to have two receivers with output connected to the same line, only one active at the time. So I just want to be sure that when the ADN4662 is powered-off its output is tristated.

If this is correct, than even in absence of a dedicated enable line, I can just use a pmos to power-off the receiver.
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+1 ConalW

on May 26, 2022 9:34 AM in reply to iCarletto
Apologies, yes, ADN4662 and ADN4664 are LVDS receivers so it's the CMOS outputs that are being referred to here; they will be high impedance when the part is powered off.

Another option if you prefer would be to use our MLVDS transceivers, as these have dedicated receiver output enable, and can receive LVDS signals as well. Using our new quad MLVDS ADN4680E would mean a single IC with 7x7mm footprint, although of course this is two extra transceivers compared to what you need, and you don't need the TX capability.
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0 iCarletto on May 26, 2022 9:49 AM in reply to ConalW

Thanks for the tip
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