N/C pins of BBD

[armdnrdy]

I decided to pull out my BBD tester project to make some more progress. (it's getting close)

The positive voltage BBD tester will be able to test the MN3209, 3204, 3207, 3208, 3205, and the SAD1024 with three Ziff sockets.

The negative voltage BBD tester will be able to test the MN3009, 3004, 3007, 3008, 3005, and the TDA1022 with three Ziff sockets.

I would like to be able to test the MN3010 as well without adding another Ziff socket. As it stands, the "A" half of the 3010 could be tested for 512 stages in the 3004 socket as the 3004 and the 3010 have the same pin out save for the lower half of the 3004 having six N/C pins, which leads me to my question.

I understand that N/C IC pins are just that....not connected internally but!....is there any chance of an adverse effect by connecting input, output, and clock signals to these N/C pins?

I want to make a BBD tester not a BBD killer!

Here's the data sheet page showing the pin outs.

And can someone please tell me how to reduce a posted image so it doesn't show up "Gigantor" sized.

[Fender3D]

Usually BBD nc pins should be connected to GND , according to datasheet...
If my memory serves well, BBD suffered from static badly, early chips were stored and sold with aluminum foil, shorting pins... and I guess single stage chip are/were dual stages with a faulty or deactivated stage, part of their high price were rejected defective units by the way...

I don't know what happens if you apply clock and signal, I think it's not harmfull... but you may add 6 caps jumpers (as those on PC motherboards) or a 6 way dipswitch to set the proper socket...

[armdnrdy]

Hi Federico,

Thank you for the reply.

I also thought of switching the socket pins with a rotary switch but the area underneath of the top of the enclosure has a dedicated Ziff socket PC board with a few components. There really isn't a good place to put a switch.

I looked over the data sheets again (Panasonic BBD Manual) and I can't find mention of grounding the N/C pins.

Here's the MBN3010 application circuit:



and here is the MN3010 circuit and pin assignment:



If you look at the isolated pin on the bottom left, that should be pin 7. ( the rest of the pins are accounted for)

[armdnrdy]

I just found this thread:

http://www.diystompboxes.com/smfforum/index.php?topic=31272.0;prev_next=prev

So....even though an internal connection is not shown on the data sheet, It's probably a good idea to leave it unconnected.

[R.G.]

The bad news is that "NC" pins on ICs come in all three flavors - OK to connect to something, often ground,  explicitly must NOT be connected to anyplace else, as it's used in factory testing, and simply not connected inside, a blank pin.

Sometimes the datasheet tells you, sometimes you find out by converting it into a light emitting IC.  It's quite difficult to state any general rule unless the datasheet actually says something about them.

[armdnrdy]

Thanks R.G.

I believe it's on to plan "B" ......finding room for a switch.