NJU7660D Problems

[nirvanas silence]

I built a negative voltage circuit using this circuit for the Maestro sample/hold filter pedal and its putting out only .5V on the negative terminal.  I can always build a new circuit, but I am curious why it doesn't work anymore.  Does anyone have a schematic that they know works for it in this application?

[puretube]

pin-out???

[mikeb]

Look at the datasheet, or at RGs layout for his Neutron - all the information you seek is there!

Mike

[nirvanas silence]

I built it according to the datasheet and it fried the chip and I was trying to see if it was a bad chip or if it didn't work in that application.

[mikeb]

Perhaps the 7660 doesn't supply enough current for that circuit? I must admit I've had some similar failures with 7660s/1044s recently, and am pulling my hair out wondering why.  :cry:

Mike

[R.G.]

1) pinout wrong
2) circuit mistake or short
3) reversed capacitor pinout

Just where I'd start looking.

[nirvanas silence]

Pinout was checked, so was both caps, and the wiring was checked.  It isn't my fault.  

[Paul Perry (Frostwave)]

Pinout was checked, so was both caps, and the wiring was checked.  It isn't my fault.  

You know, I've often BELIEVED that, but I've never had the balls to SAY it :roll:
What I'd do (and, I've been places like this before!) is to build the ckt again, but with just a 1K resistor as load, and see how it behaves then.
If it runs OK, then you must have sucked too much current from it the first time.

[R.G.]

Pinout was checked, so was both caps, and the wiring was checked. It isn't my fault.

Cool. Now that we got that out of the way, what's left???

Hmmm... load and inverter chip, right?

So cut the load away, use a 1K resistor as a temporary load, as Paul says (hard to mess those up), and a new chip. If it works then, put the old chip back in. If it still works, you have a load fault. If it doesn't, you still have a load fault, but one that killed the first chip.

Me personally, I like finding out I did a forehead-slapper instead of the (usually) messier alternatives...