I have implemented a -6V and -15V power with the ADP5074. neither will turn on. I am including a snip of the schematic with these 2 devices. Show me the fatal error.
1. Please increase EN voltage (R432, R420) to meet 2.8V rising threshold
2. COMP pin values of -15V circuit: have values close to recommended in Table 9 of datasheet
If the other boards are working, its a good sign that you don't have issue with design. It must be manufacturing issue. Make sure that everything is properly mounted specially the IC. You may want to…
Can you try start-up while both outputs are at no load? The output load may be too much or there is too much capacitance at the load other than your schematic. Take note that the datasheet current you see is not the output current but inductor current. This is higher than the output current. If issue persists, can you give me scope shot of VIN, VOUT and VSW?
The parts on the #1 board are both BAD. I powered up board #@ and both parts are working. here are the waveforms
ch1 -yellow V_in 12V
CH2 Blue Vout
CH4 green Vsw
there is a little "noise" on the switch/output but nothing like what I expect from the switching waveform.
Thanks for your help
If the other boards are working, its a good sign that you don't have issue with design. It must be manufacturing issue. Make sure that everything is properly mounted specially the IC. You may want to troubleshoot using meter several nodes impedance and compare with a good board.
The waveforms I asked was assuming you had issue with design. Everything is flat in the steady-state. It means IC is not even responding and not enabled. Waveforms during start-up may also help in the analysis. But I think what you have is board issue and should be addressed by basic troubleshooting methods.