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ADA4932 /PD pin

Question asked by RFRM on Aug 4, 2011
Latest reply on Sep 2, 2011 by RFRM

Update to a problem I found with an ADA4932-1 concerning the PD pin.

 

I have two circuits using this device, one is a balanced MFB active filter, the other a 2X analog line driver.

 

The MFB active filter uses a single 5V supply, the bus driver uses a symmetrical +-4.25V supply.

 

Both circuits use the /PD pins to conserve power.

 

The problem I see is that enabling the active filter at low temperatures, causes BOTH +ve and -ve outputs of the device to go to the positive rail (or at least within 1.2V of the rail). This condition can last 100s of milliseconds, depending on the temperature, so it seems like a leakage current issue combined with some capacitive charging/discharging.

 

The analog line driver does not suffer from this problem, either because the /PD function works as expected with the dual supply, or because there are no (large-ish) capacitors in the feedback network (as is the case for the active filter).

 

My question is, does the /PD function work properly with a single supply ?

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