LM43601: 15V to -15V

Hello

TI is blocking the link to your schematic.

Please provide a PDF schematic.

Also, have a look at the attached documents for more information on the IBB.

Thanks

8764.snva722b.pdf0830.snva856a.pdf

I've attached a PDF of the schematic. I read SNVA722B prior to designing this circuit, however SNVA856A is new to me so I shall certainly have look through that. 

Additionally, I have attached a capture from the scope which may help shed more light.

schematic (1).pdf-15V (not atten).pdf

Hello

Try to short out L6 and test again.

Also, R124 should be eliminated; the PGOOD pin is only a 12V pin.

Thanks

Hello

The SYNC pin should not be floating.  Connect to regulator GND=-15Vout.

Thanks

Hi Frank,

Thanks for getting back to me.

Unfortunately none of those suggestions have fixed the problem. Rpg has been removed and pin 8 is now floating. SYNC pin 6 has been jumpered to the -15V side of C86.

I have attached the scope captures of SYNC tied to -15V with and without L6 shorted.

SYNC tied to -15V.pdfSYNC tied to -15V and L6 shorted.pdf

Hello

What load are you applying and what kind of load ??

Thanks

The -15V goes to a 7912 fixed -12V regulator which in turn supplies 16x dual channel opamps. 

There are a couple of things we will be trying tomorrow. Will report back if anything comes of that. Also working on a new 'dev board' with a different regulator to see how that goes.

Hello

I would suggest to get the IBB working on an EVM first.  This device should have no

issues working in your application.

Thanks

Prepared a new dev board with a few different options for the -15V, so hopefully something comes good from that.