LM723 adjustable bench PSU not working

[eccerr0r]

Re: LM723 adjustable bench PSU not working

I think I just either killed a LM723 or have a dead LM723 in my hands. I'm not sure if I tried feeding in the entire 12V+ output voltage back to the negative input of the error amplifier or not, but now with a voltage divider there, it seems stuck at 0.9V...

That's when I read the datasheet: absolute maximum input is 8.5 volts....

so I might have killed it... One dead LM723!

[Dannyx]

Re: LM723 adjustable bench PSU not working

I think I just either killed a LM723 or have a dead LM723 in my hands. I'm not sure if I tried feeding in the entire 12V+ output voltage back to the negative input of the error amplifier or not, but now with a voltage divider there, it seems stuck at 0.9V...

That's when I read the datasheet: absolute maximum input is 8.5 volts....

so I might have killed it... One dead LM723!

And here I was thinking those things are virtually indestructible

[eccerr0r]

Re: LM723 adjustable bench PSU not working

Hmm... I dug up all the µA723/LM723/MC1723's I could find ... they all behave differently? Weird. Need to see if I can hack up a test jig and toss the broken ones if there are any (some are untested pulls...)

[eccerr0r]

Re: LM723 adjustable bench PSU not working

I tested the chip that I thought was dead in a reference design... it works despite its behavior is different than another 723 I had (by another manufacturer)!
WTF? Maybe these really are indestructible *shrug*. My test circuit must be bad or differential between the +/- is over 5 volts, though it too didn't destroy it...

Tested three of them in the jig, they seem to regulate OK, weird...