ADAU1452 exposed pad not connected symptoms

hi Dave,

it is strongly suggested that the EPAD should connect to GND in data sheet.

in the end of page 20, bottom of the table, it said: "The exposed pad must be grounded by soldering it to a copper square of equivalent size of the PCB..."

in the page of 171, around figure 83 and figure 84, it said:"The ADAU1452 package includes an exposed pad for improved heat dissiption. When designing a board for such a package, give special consideration to the following:..."

so it's better to re-solder the 1452 if your place GND copper square during PCB layout, and try again.

if no copper sqaure placed in your PCB board, it's better to layout again.

HENRY

Hi Dave,

may I ask how you assemble your prototype boards? I experienced that the package of the 1452 is quite easily to handle for prototyping. I use a manufactured solder paste stencil for preparation. In combination with preheater and hot air it is really easy to do.

If you added a center pad and maybe missed to heat all up maybe the solder paste is not cured under the IC and prevents connection of the outer pins?

Beste regards

The boards have the thermal pads as required under the part. I suspect that

the exposed pad on the part has not made connection (soldered) to the pad

on the board.

What I wanted to know is, whether this lack of connection would prevent the

part from working at all ? After all, all the other Ground pins are

connected ? I can see that the ADAU1452 is not drawing any current at all.

On Fri, Jul 8, 2016 at 3:12 PM, Olombo <

It's a fair and worthwhile question, as hand-building these parts can be challenging without specialized equipment (preheater, air gun, custom stencil as above). Lots of us want to avoid buying special equipment just to develop with these chips.

I have prototyped the ADAU1452 without soldering the thermal pad, and it seems to work fine; I suspect your issue is elsewhere. I used a bit of thermal grease (non-electrically-conductive). No issues operationally that I've found.

But how is it getting warm if no current is being drawn?

Hi Joe,

The part is NOT getting warm. I will try and remove the part and re-solder

and see if it works. Will let you know what happens (if I don't destroy the

part in the process!) Was curious as to what the bottom pad does

electrically - how is it different from the other Ground pins.

Dave

On Fri, Jul 8, 2016 at 6:40 PM, joe42 <

My mistake, I misread. I would certainly encourage trying again. It's possible my thermal pad is making incidental electrical contact, but I tend to doubt it.

It would be nice to have a definitive answer from ADI though.